Дисертації з теми "Chemical risk assessme"
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1
Beeston, Michael Philip. "Chemical availability of arsenic - measurement and risk assessment." Thesis, University of Exeter, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532015.
2
Gatnik, Mojca Fuart. "Computational methods in support of chemical risk assessment." Thesis, Liverpool John Moores University, 2016. http://researchonline.ljmu.ac.uk/4045/.
Анотація:
Chemical risk assessment for human health effects is performed in order to establish safe exposure levels of chemicals to which individuals are exposed. The process of risk assessment traditionally involves the generation of toxicological studies from which health based guidance values are derived for a specific chemical. For low level exposures to chemicals, where there are no or limited chemical specific toxicity data, the application of the Threshold of Toxicological Concern (TTC) approach may estimate whether the exposure levels can be considered safe. The TTC approach has recently gained increasing interest as new requirements, under different regulatory frameworks, emerge for the safety assessment of chemicals and to assess chemicals for which testing is not routinely required. The application of TTC relies heavily on computational (in silico) methods. In silico tools are computer implemented models that, based on commonalities in the toxicity of “similar” chemical structures, may predict hazard. In silico methods are rapidly evolving and gaining importance within the context of Integrated Approaches to Testing and Assessment (IATA) and their acceptance for regulatory purposes is expanding. The work presented in this thesis has focused on the use and applicability of a wide range of computational approaches to assist in the application of the TTC concept. In the TTC approach, the identification of genotoxic chemicals is a primary requirement. In silico approaches apply expert knowledge and/or statistical methods to either predict genotoxicity or to identify structural alerts associated with it. This thesis focused, in part, on a group of important environmental pollutants, nitrobenzenes, to assess the applicability of in silico tools to predict genotoxicity. For this purpose a dataset containing 252 nitrobenzenes including Ames test results was compiled. Based on these test results a case study for sodium nitro-guaiacolate, a pesticide active substance, was developed. The case study demonstrated that (Q)SAR and a category approach incorporating read-across, are applicable for the prediction of genotoxicity and supports their use within a weight of evidence approach. Another aspect of the TTC approach is the evaluation of repeat dose, non-cancer endpoints. For that purpose chemicals are separated into groups related to three levels of concern based on the Cramer classification. For each level, namely the Cramer Classes (I, II and III), a safe exposure level has been established. Therefore, as interest to apply TTC expands to new groups of chemicals, the reliability and conservativeness of the established thresholds relative to Cramer Classes for the new chemistries must be established. In this thesis the TTC approach was evaluated for 385 cosmetic ingredients, 77 biocides and 102 compounds classified as reproductive and developmental toxicants. To support the evaluation at different levels, chemical datasets containing toxicological data were utilised and computational tools were applied to compare datasets. The results indicated, that the historical “Munro” dataset is broadly representative for cosmetics and biocides. In addition, that the threshold levels for Cramer Class III are within the range of Munro’s threshold further supports the validity of the TTC approach and its conservativeness for the groups of chemicals analysed. Cramer Class I thresholds were found to be valid only for classified developmental and reproductive toxicants. The results also supported the validity of the classification of chemicals into Cramer class III. It is foreseen that the TTC approach will gain increasing acceptance in the risk assessment of different groups of chemicals. Therefore it is emphasised that the future work should focus on the identification of the limitations of the application of TTC, including the identification of groups of chemicals to which TTC cannot be applied, the expansion of the underlying toxicological datasets, and the development of tools to support the application of TTC so that is transparent and acceptable for regulatory purposes.
3
Marshall, Rafael. "An investigation of risk homeostasis in a laboratory environment." Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/41685.
Анотація:
This study investigated whether risk compensation behavior would occur during a chemistry experiment due to the presence of protective equipment. This study also examined whether a homeostatic regulating mechanism exists for risk-taking behavior. Risk compensation and a homeostatic regulating mechanism for risk-taking behavior are both encompassed within the Risk Homeostasis Theory, which states that people accurately perceive and fully compensate for changes in risk.
Thirty-six subjects performed three trials of a short chemistry experiment either with protective equipment or without protective equipment during the first of two sessions. After the first session, half the subjects were required to switch from wearing protective equipment to not wearing protective equipment, or from not wearing protective equipment to wearing protective equipment. The time required to complete the task, the number of errors committed, and subtask measurement accuracy were tabulated.
Between-subject analyses did not reveal risk compensation behavior. Moreover, within-subject comparisons failed to show a significant risk compensation effect or the presence of a homeostatic regulating mechanism for risk-taking behavior. The results suggested that the Risk Homeostasis Theory may not explain sufficiently changes in behavior due to increases (or decreases) in perceived risk. The limitations of the present study were discussed. Suggestions and examples for research on different aspects of the Risk Homeostasis Theory were also provided.Master of Science
4
Critto, Andrea <1971>. "Enviromental risk assessment for the exposure to chemicals." Doctoral thesis, Università Ca' Foscari Venezia, 2004. http://hdl.handle.net/10579/528.
Анотація:
Preliminarmente è stata condotta una review relativa agli sviluppi dell'analisi del
rischio ambientali avvenuti nell'ultimo decennio, comprendente una presentazione
delle metodologie attualmente applicate nel contesto internazionale.
Tale review ha permesso di identificare i principali aspetti problematici e le sfide che
condizionano la ricerca presente e futura, finalizzata allo sviluppo dell'analisi di
rischio ambientali. Essi comprendono: a) l'integrazione dell'analisi di rischio
ambientale all'interno dei processi di gestione del rischio; b) lo sviluppo di strumenti
in grado di fronteggiare le problematiche connesse alle scale spaziale, temporale e di
effetto, che caratterizzano le diverse fasi dell'analisi del rischio; c) l'armonizzazione di
metodologie e strumenti; d) lo sviluppo di metodologie e strumenti per l'analisi di
rischio probabilistica e l'analisi dell'incertezza; e) la comunicazione dei risultati e delle
decisioni.
In accordo con tali aspetti problematici, gli obiettivi principali della tesi sono stati: a)
l'integrazione dell'analisi di rischio ambientale e della gestione del rischio mediante la
definizione di strategie di analisi di rischio basate su diversi livelli di approfondimento
di analisi e lo sviluppo di sistemi di supporto alle decisioni basati sull'analisi del
rischio; b) l'implementazione di tecniche statistiche e geostatistiche e di strumenti
GIS, finalizzate alla trattazione delle problematiche relative alla scala spaziale nella
quantificazione del rischio ed all'analisi dell'incertezza associata.
L'investigazione di un caso di studio particolarmente complesso e intemazionalmente
rilevante, quale la laguna di Venezia, ha permesso di testare e corroborare gli
approcci e le metodologie proposte, enfatizzando il ruolo dell'analisi di rischio
ambientali all'interno di un efficace processo decisionale e gestionale.
Basandosi sui singoli risultati ottenuti dalle attività di ricerca condotte all'interno della
presente tesi, recentemente pubblicati o sottomessi per la pubblicazione su riviste
scientifiche internazionali (vedasi gli articoli allegati e la lista dei contributi), e al fine
di evidenziare l'analisi di rischio ambientale come un approccio interdisciplinare e,
come tale, un argomento fondamentale per lo sviluppo delle Scienze Ambientali, qui
vengono riportati gli specifici contributi della presente tesi relativi alla chimica
ambientale, ecologia, ecotossicologia, statistica e geostatistica, modellistica
ambientale e di valutazione del rischio, e finalizzati alla definizione di uno schema
generale sistematico per l'analisi di rischio ambientale.
Tale schema è stato ottenuto mediante: a) lo sviluppo ed applicazione di un'analisi di
rischio ecologica a diversi livelli di approfondimento di analisi, comprendente l'analisi
spaziale e strumenti GIS, in grado di supportare il monitoraggio ambientale per la
Laguna di Venezia; b) lo sviluppo ed applicazione di un sistema di supporto alle
decisioni, basato sull'analisi del rischio, per la riqualificazione del sito contaminato di
rilevanza nazionale di Porto Marghera; c) la definizione di linee guida nazionali per
l'analisi di rischio ecologico per siti contaminati; d) lo sviluppo ed applicazione di
specifici strumenti statistici e geostatistici per la caratterizzazione dell'esposizione; e)
l'applicazione dell'analisi di rischio probabilistica e dell'analisi dell'incertezza.
A review of environmental risk assessment developments over the last ten years,
including a presentation of current methodologies applied worldwide, was
preliminarly carried out.
This review identified the following open issues and challenges as the most important
for advancing the practice of environmental risk assessment: a) integration of risk
assessment and risk management; b) refinement of tools to account for spatial,
temporal and effects scales; c) harmonization of methodologies and tools; d)
development of methodologies and tools to support probabilistic risk assessment and
uncertainty analysis; e) communication of the results and the decision.
Accordingly, main objectives of this thesis were: a) the integration of risk assessment
and risk management by the development of tiered risk assessment strategies and
risk based decision support systems, and b) the implementation of statistic and
geostatistic techniques and GIS tools. This implementation aimed at including spatial
scale in environmental risk quantification and analysing the uncertainty related to risk
assessment.
Investigation of an internationally relevant and particularly complex case study, such
as the Lagoon of Venice, was a valid training-ground for testing and corroborating the
proposed approaches and methodologies, and permitted to emphasize the
integration of environmental risk assessment into an effective decisional and
management process.
Based on individual results obtained by the thesis research activity, which have been
recently published or submitted for publication on international journals (see attached
papers and list of contributions), and to highlight environmental risk assessment as
an interdisciplinary approach and consequently as a fundamental topic for the
development of Environmental Sciences, here we report our own contributions of
environmental chemistry, ecology, ecotoxicology, statistic and geostatistic,
environmental and assessment models, to the definition of a systematic framework
for environmental risk assessment.
This framework was attained through: a) the development and application of a tired
ecological risk assessment, using spatial analysis and GIS tools, in support of
environmental monitoring for the lagoon of Venice; b) the development and
application of a risk based decision support system for rehabilitation of the Porto
Marghera contaminated site; c) the definition of ecological risk assessment
guidelines for contaminated site; d) the development and application of specific
statistical and geostatistical tools for exposure characterization; e) the application of
probabilistic risk assessment and uncertainty analysis.
5
Shaw, Brenda Jo. "Evaluation of risks to human health in Hong Kong from consumption of chemically contaminated seafood : a risk assessment approach /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B14723657.
6
Czarnota, Jenna. "Modeling Spatially Varying Effects of Chemical Mixtures." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4361.
Анотація:
Cancer incidence is associated with exposures to multiple environmental chemicals, and geographic variation in cancer rates suggests the importance of accommodating spatially varying effects in the analysis of environmental chemical mixtures and disease risk. Traditional regression methods are challenged by the complex correlation patterns inherent among co-occurring chemicals, and the applicability of geographically weighted regression models is limited in the setting of environmental chemical risk analysis. In comparison to traditional methods, weighted quantile sum (WQS) regression performs well in the identification of important environmental exposures, but is limited by the assumption that effects are fixed over space. We present an extension of the WQS method that models spatially varying chemical mixture effects called local weighted quantile sum (LWQS) regression, and assess through a simulation study its ability to identify important environmental risk factors over space. We use two different approaches to estimate the LWQS model based on variable subspaces. One uses an ensemble of variable subsets of the same size, and the other selects the best subset over a range of candidate subset sizes according to the model goodness-of-fit. We assess the performance of both estimation methods in simulated scenarios that incorporate increasingly complex levels of spatial dependency in the model, and consider correlation patterns from observed exposure data. The results demonstrate that LWQS has the ability to replicate spatially dependent mixture effects and can correctly identify important exposures in a mixture of environmental chemicals. In all scenarios, the best subset approach correctly chose an index containing only the important chemicals and improved on the accuracy of the chemical importance weights in comparison with the ensemble solutions. Future work will evaluate if the ensemble subset approach has better relative performance with larger chemical mixtures of highly correlated components.
7
Pan, Jilang. "Environmental risk assessment of inorganic chemicals in mining environment." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5641.
Анотація:
Mining is one of the human‟s earliest industrial activities. Indeed early civilizations such as the Bronze Age and Iron Age are named according to their use of metals; the importance of metals is still central to industrialization and urbanization. The enormous quantities of mine waste and tailings generated by mining every year however, are also of concern. The relocation and removal of large quantities of mineral and waste can also release chemicals into the environment especially surface water, groundwater and soil during the mining lifecycle if good mining engineering and mitigation are not performed. To optimise this risk management based on excellent risk analysis is required. The study analysed the mining life cycle, chemicals in the mining environment, current regulations on chemicals in the environment and the development of environmental risk assessment framework with particular focus on the inorganic substances. Chemicals in the mining environment were then grouped into a) the minor constituents of the ore deposits; b) chemicals used in mining such as explosives, leaching chemicals and froth flotation reagents. c) chemicals generated by mining, milling and smelting including Acid mine drainage (AMD) and emissions from smelting and refining. The natural and anthropogenic sources, potential pathways to environmental and human receptors and the implications on human health of key toxic metals and metalloids in the mining context were then evaluated. A new two-tier risk assessment was developed based on the four-step conventional risk assessment framework by the U.S.National Research Council (NRC). Tier 1 involved analysing and evaluating existing data using two new semi-quantitative risk screening and prioritisation procedures, namely Chemicals of Greatest Concern (CGC) and Media of Greatest Concern (MGC). CGC was developed using specific hazardous properties of the inorganic chemicals and their eco-toxicities in the environment. MGC was a system of decomposition using a combination of various decision-making tools such as Multi-criteria decision making (MCDM) and Hierarchical holographic modelling (HHM) to facilitate hazard identification and assessment. Tier 2 involved quantitative toxicity assessment, exposure assessment and risk characterisation which were used to quantify the total risk to human health using Monte Carlo simulations (MCS). The tiered risk-based approach developed was evaluated using three cases studies, viz, the Rustenburg platinum (Pt) mine, South Africa; the Lisheen lead (Pb) – zinc (Zn) mine, Ireland and the Richmond copper (Cu) smelter. The results from them were evaluated and compared as a basis for Anglo American plc‟s global strategic decision making. Finally, the strengths and weakness of the methodology developed were evaluated in relation to the application at current operational level. Future methodology refinement and incorporation of organic chemicals were also discussed.
8
Schenk, Linda. "Management of chemical risk through occupational exposure limits." Licentiate thesis, KTH, Philosophy and History of Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9769.
Анотація:
Occupational Exposure Limits (OELs) are used as an important regulatory instrument to protect workers’ health from adverse effects of chemical exposures. The OELs mirror the outcome of the risk assessment and risk management performed by the standard setting actor. In paper I the OELs established by 18 different organisations or national regulatory agencies from the industrialised world were compared. The comparison concerned: (1) what chemicals have been selected and (2) the average level of exposure limits for all chemicals. In paper II the OELs established by 7 different national regulatory agencies of EU member states are compared to those of the European Commission (EC). In addition to the same comparisons as performed in the first study a comparison level was introduced (3) the similarity between the OELs of these EU member states and the OELs recommended by the EC.
List of OELs were collected through the web-pages of, and e-mail communication with the standard-setting agencies. The selection of agencies was determined by availability of the lists. The database of paper I contains OELs for a total of 1341 substances; of these 25 substances have OELs from all 18 organisations while more than one third of the substances are only regulated by one organisation alone. In paper II this database was narrowed down to the European perspective. The average level of OELs differs substantially between organisations; the US OSHA exposure limits are (on average) nearly 40 % higher than those of Poland. Also within Europe there was a nearly as large difference. The average level of lists tends to decrease over time, although there are exceptions to this. The similarity index in paper II indicates that the exposure limits of EU member states are converging towards the European Commission’s recommended OELs. These two studies also showed that OELs for the same substance can vary significantly between different standard-setters. The work presented in paper III identifies steps in the risk assessment that could account for these differences. Substances for which the level of OELs vary by a factor of 100 or more were identified and their documentation sought for further scrutiny. Differences in the identification of the critical effect could explain the different level of the OELs for half of the substances. The results reported in paper III also confirm the tendency of older OELs generally being higher. Furthermore, several OELs were more than 30 years old and were based on out-dated knowledge. But the age of the data review could not account for all the differences in data selection, only one fifth of the documents referred to all available key studies. Also the evaluation of the key studies varied significantly.
9
Keatinge, Zoe Alexandra Frances. "Soil contamination in urban Tyneside : a chemical and biological risk assessment." Thesis, University of Newcastle Upon Tyne, 2006. http://hdl.handle.net/10443/233.
Анотація:
The extent of soil contamination with organic and inorganic pollutants in most urban areas in the UK is largely unknown but due to past and present industrial activity it is likely that pollutant levels are high. Such contamination could have a serious impact on human health. Therefore this thesis set out to examine the extent of soil contamination within Newcastle upon Tyne with a focus on the contribution of an incinerator (Byker) to contamination levels of urban soils. The Byker incinerator is situated in central Newcastle and has been the subject of much media controversy due to the disposal of incinerator ash on local allotments. The current work extended past investigations to see if the incinerator had contributed to general urban soil pollution (heavy metals and dioxins) by aerial deposition and allowed a useful investigation into levels of urban soil contamination in Newcastle. In addition to examining metal and dioxin levels the bioaccessibility (human and bacterial) of pollutants in selected soil samples was estimated and an attempt to develop a human cell based soil toxicity assay made. These measurements permit a preliminary assessment of risk to human health from soil contamination. A total of 163 soil samples were collected based on predicted aerial deposition from the Byker incinerator and analysed for dioxins and heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb & Zn) content (mg pollutant /kg soil). A high proportion of samples (90/163) had contamination levels above soil guideline values (as proscribed in current UK regulations; CLEA). The highest dioxin levels were South West of the incinerator (1911 ng I-TEQ/kg) and the congener profiles coupled with a detailed historical survey demonstrated that the source of contamination was likely to be an old alkali works and not the incinerator. Overall it was found that the incinerator did not contribute significantly to dioxins found in the urban soils except those in the incinerator plant grounds. Soil metal contamination levels varied but were not related to incinerator deposition. Many samples contained levels of heavy metals well over soil guideline values with the highest values being found for Cu (12,108 mg/kg), Pb (4,134 mg/kg) and Zn (4,625 mg/kg) To determine the potential human health risk associated with heavy metal contaminated soils, selected samples (16) were subjected to two in vitro digestion techniques which simulate the bioaccessibility of metals (Cu, Ni, Pb & Zn) to humans in case of soil ingestion. Only three samples had high levels of metal availability (over SGV's) indicating that these soils should be subjected to further risk assessment. All other samples tested had low metal availability most likely due to a combination of metal speciation, and complexation to soil particles over time. An attempt was made to develop a human cell based system to determine the toxicity of contaminated soil. Using an in vitro system, human liver cells (HepG2's) were exposed to extracts from soils; cytotoxic effects (membrane integrity, metabolic capability and oxidative stress status) and genotoxicity potential (DNA damage) of Cu and Zn were first investigated in order to standardise the biological assays used. Between 0.1 and 10 mg/L Cu caused DNA damage and higher concentrations caused cytotoxicity. Zn was also proven to cause genotoxic effects from O. lmg/L. From 10 mg/L cytotoxic responses occurred and DNA damage could be attributed to cell death. Due to difficulties in sterilising soil extracts and physical damage caused to HepG2 cells by the abrasive nature of soil, it was not possible to elucidate whether metal contaminated soil extracts were capable of causing a cytotoxic or genotoxic response in human liver cells. Finally, the same soil samples were then subjected to a bacterial (lux) biosensor technique to examine soil toxicity. Interestingly, despite the high levels of contamination found, none of the soil samples were found to be toxic to the two Pseudomonas strains used which again indicates a low level of ecosystem risk and suggests that most of the contaminants present are either in a form that is unavailable to living microbes or are complexed to soil particles. In summary, this research has shown that the high level of soil contamination of urban areas in Newcastle is due to past industrial activity and a similar situation is likely in most other urban areas of the UK and internationally. The high cost of remediation means that if contaminated sites are shown to be a potential risk then bioaccessibility of contaminants should be examined in order to provide a more realistic assessment of the need for remediation. This work demonstrates that only a small proportion of urban contaminated sites are likely to require remediation based on bioaccessibility determination measurements.
10
Consolazio, Nizette A. "Chemical Interactions of Hydraulic Fracturing Biocides with Natural Pyrite." Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/1071.
Анотація:
In conjunction with horizontal drilling, hydraulic fracturing or fracking has enabled the recovery of natural gas from low permeable shale formations. In addition to water, these fracking fluids employ proppants and up to 38 different chemical additives to improve the efficiency of the process. One important class of additives used in hydraulic fracturing is biocides. When applied appropriately, they limit the growth of harmful microorganisms within the well, saving energy producers 4.5 billion dollars each year. However, biocides or their harmful daughter products may return to the surface in produced water, which must then be appropriately stored, treated and disposed of. Little is known about the effect of mineral-fluid interactions on the fate of the biocides employed in hydraulic fracturing. In this study, we employed laboratory experiments to determine changes in the persistence and products of these biocides under controlled environments. While many minerals are present in shale formations, pyrite, FeS2(s) is particularly interesting because of its prevalence and reactivity. The FeII groups on the face of pyrite may be oxidized to form FeIII phases. Both of these surfaces have been shown to be reactive with organic compounds. Chlorinated compounds undergo redox reactions at the pyrite-fluid interface, and sulfur-containing compounds undergo exceptionally strong sorption to both pristine and oxidized pyrite. This mineral may significantly influence the degradation of biocides in the Marcellus Shale. Thus, the overall goal of this study was to understand the effect of pyrite on biocide reactivity in hydraulic fracturing, focusing on the influence of pyrite on specific functional groups. The first specific objective was to demonstrate the effect of pyrite and pyrite reaction products on the degradation of the bromine-containing biocide, DBNPA. On the addition of pyrite to DBNPA, degradation rates of the doubly brominated compound were found to increase significantly. DBNPA is proposed to undergo redox reactions with the pyrite surface, accepting two-electrons from pyrite, and thus becoming reduced. The primary product is the monobrominated analogue of DBNPA, 2-monobromo-3-nitrilopropionamide (or MBNPA). The surface area-normalized first-order initial degradation rate constant was found to be 5.1 L.m-2day-1. It was also determined that the dissolution and oxidation products of pyrite, FeII, S2O32- and SO42- are unlikely to contribute to the reduction of the biocide. Taken together, the results illustrate that a surface reaction with pyrite has the ability to reduce the persistence of DBNPA, and as a consequence change the distribution of its reaction products. The second objective was to quantify the influence of water chemistry and interactions with pyrite on the degradation of the sulfur-containing biocide. Dazomet readily hydrolyzes in water due to the nucleophilic attack of hydroxide (OH-) anions. Thus the half-life of dazomet during the shut-in phase of hydraulic fracturing will decrease with increasing pH: 8.5 hours at pH 4.1 to 3.4 hours at pH 8.2.Dazomet degradation was rapidly accelerated upon exposure to the oxidized pyrite surface, reacting five times faster than hydrolysis in the absence of pyrite at a similar pH. The products measured were identical to those identified on hydrolysis (methyl isothiocyanate and formaldehyde) and no dissolved iron was detected in solutions. This suggests that the dithiocarbamate group in dazomet was able to chemisorb onto the oxidized pyrite surface, shifting the electron density of the molecule which resulted in accelerated hydrolysis of the biocide. The third objective explored the reactivity of various biocide functional groups due to the addition of pyrite. Several elimination mechanisms were identified, and tied to the reactivity of the specific functional group involved. The addition of pyrite led to accelerated degradation of dibromodicyanobutane. This is because the bromine (-Br) group is easily reduced. For methylene bis(thiocyanate), hydrolysis was a noteworthy elimination mechanism since the thiocyanate (-SCN) functionality is a good leaving group. Benzisothiazolinone and methyl isothiazolinone were stable at low pH due to the stabilizing donor-acceptor interactions between the organic biocides’ carbonyl (–C=O) groups and salts in the solution. This body of work has illustrated that pristine pyrite can undergo redox reactions with brominated biocides used in hydraulic fracturing, reducing their persistence and altering the product distribution. This will change the efficacy and the risks associated with the use of these biocides in shales containing pyrite, particularly at lower pH where organic compounds are more stable to hydrolysis. However, at higher pH hydrolysis becomes more important, and additional studies will need to be conducted to investigate the pyrite contribution under these conditions. Conversely, the FeIII surface groups on oxidized pyrite can catalyze the hydrolysis of dazomet and may do so for other labile, sulfur-containing biocides as well. Overall, this research has shown that the physicochemical properties (such as the acid dissociation constant and the standard reduction potential) that govern the environmental reactivity of a molecule can be used to anticipate its reactivity in hydraulic fracturing.
11
Pennington, Daniel. "Chemical facility preparedness a comprehensive approach." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Sep%5FPennington.pdf.
Анотація:
Thesis (M.A. in Security Studies (Homeland Security And Defense))--Naval Postgraduate School, September 2006.Thesis Advisor(s): Ted Lewis. "September 2006." Includes bibliographical references (p. 83-88). Also available in print.
12
Henri, Christopher. "Risk managment of complex aquifers contaminated by chemical mixtures : numerical tools and human health risk assessment." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/316393.
Анотація:
Human impact on groundwater resources has led to a rapid growth of social concerns worldwide owing to an increasing presence of toxic chemicals released in the subsurface. Risk assessment provides the scientific tool needed to quantify the actual thread that these potential hazards pose to human health. Specifically, risk analysis enables decision makers to answer: What can happen? How likely is it to happen? What can be the consequences? Risk assessment is in this context essential. However, modeling efforts involve in risk analysis are still facing several problems. Among them, in some cases, degradation products can constitute new noxious chemical compounds not necessarily less toxic than their parent product. Thus, the original pollutants and their daughter products are susceptible to co-exist in the aquifer forming a hazardous chemical mixture composed of products of different toxicity. This renders the quantification and interpretation of human health risk a non-trivial and challenging task. Also, the lack of information in the hydraulic and biochemical properties renders transport predictions to be highly uncertain. Stochastic human health risk assessment incorporates hydrogeological uncertainty in human health predictions. This way, probabilistic risk models can be used to determine the likelihood of risk exceeding a given regulatory threshold value or the expected threat to the exposed population and its uncertainty. Unfortunately, these approaches are very computationally demanding. Moreover, the diverse mineralogical composition of a real soil and the complex spatial variability of aquifer properties can produce a mixture of rates of mass transfer between regions of mobile and immobile contaminants. Finally, risk predictions are typically challenged by the complexity of the source zone condition.
Existing reactive transport models based on Eulerian methods still undergo computational burden and numerical problems when modeling strong hydro-biochemical heterogeneities with complex reactions in multi-porosity systems. In this context, Particle Tracking Methods constitute a feasible alternative but these methods are limited in the range of applicability. The work presented in this thesis proposes an efficient particle tracking solution capable to simulate serial-parallel degradation reactions in multiple porosity systems with rate-limited mass transfer and strong heterogeneities. The method is then used to characterize the human health risk posed by chemical mixtures in highly heterogeneous porous media under complex source zone conditions. In particular, we investigate the interaction between aquifer heterogeneity, connectivity, contaminant injection mode and chemical toxicity in the probabilistic characterization of health risk. We illustrate how chemical-specific travel times control the regime of the expected risk and its corresponding uncertainties. Results indicate conditions where preferential flow paths can favor the reduction of the overall risk of the chemical mixture. The overall human risk response to aquifer connectivity is shown to be non-trivial for multi-species transport. This non-triviality is a result of the interaction between aquifer heterogeneity and chemical toxicity. To quantify the joint effect of connectivity and toxicity in health risk, we propose a toxicity-based Damköhler number. Results also show that the degradation capacity of immobile water regions and the mass depletion model can play a significant role on the spatiotemporal behavior of the contaminant mixture. Our work furthermore highlights the potential impact of the water flux passing through the source zone on the effective increased lifetime cancer risk due to a reactive chemical mixture. Counter-intuitively, the source zone efficiency is shown to have a beneficial effect on the risk. The total risk tends indeed to decrease for high source zone efficiency due to the consequential decrease in travel times near the source zone.El impacto humano sobre los recursos hídricos que forman los acuíferos es actualmente una de las grandes preocupaciones sociales en crecimiento debido a la presencia antrópica cada vez mayor de productos químicos tóxicos liberados en el subsuelo. El análisis de riesgo proporciona la herramienta científica necesaria para cuantificar el peligro real que estos contaminantes suponen para la salud humana. En concreto, el análisis de riesgo permite tomar decisiones que respondan a las siguientes preguntas: Qué puede pasar?. Qué tan probable es que suceda? Cuál pueden ser las consecuencias?. El análisis de riesgo es una herramienta clave en este sentido. Sin embargo, los esfuerzos de modelación necesarios para llevar a cabo el análisis de riesgo se enfrentan con varios problemas. Entre ellos, algunos productos tóxicos de degradación pueden constituir nuevos compuestos químicos nocivos no necesariamente menos tóxico que su producto padre. Por lo tanto, los contaminantes originales y sus productos hijos son susceptibles de coexistir en los acuíferos formando una mezcla de compuestos químicos de diferente toxicidad. Esto hace que la cuantificación e interpretación del riesgo para la salud humana sea una tarea no trivial y desafiante. Por otra parte, la falta de informaci´on en las propiedades hidráulicas y bioquímicos hace que las predicciones sobre el comportamiento de dichos contaminantes en el subsuelo sean altamente inciertas. El análisis de riesgo estocástico incorpora de forma natural la incertidumbre hidrogeológica que existe en las predicciones de riesgo para la salud humana. De esta manera, estos modelos pueden ser utilizados para determinar la probabilidad de que el riesgo supere un valor umbral o el valor esperado del riesgo y su incertidumbre. Desafortunadamente, estos enfoques son muy exigentes en tiempo de cálculo. Además de estas dos problemáticas, también se tiene que tener en cuenta que la composición mineralógica de un suelo real es diversa y variable en el espacio. Muchas veces esto implica la transferencia de masa entre zonas de contaminantes móviles e inmóviles. Esto último exige modelos sofisticados de transporte que, por ejemplo, conceptualicen el medio poroso como un sistema multi-porosidad. Finalmente, la complejidad que existe en el comportamiento del foco de contaminación hace complicado un análisis de riesgo. Los líquidos tóxicos densos y no acuosos ilustran perfectamente esta complejidad. Una vez en el subsuelo, estos líquidos liberación lentamente los contaminantes dentro del acuífero de acuerdo con una tasa de agotamiento que depende fuertemente de la arquitectura errática del foco de contaminación. Los modelos de transporte reactivo eulerianos tienen problemas numéricos cuando se simulan fuertes heterogeneidades hidro-bioquímicos en el terreno al mismo tiempo que reacciones químicas complejas en sistemas multi-porosidad. En este contexto, los métodos de trayectorias de partículas constituyen una alternativa viable. Sin embargo, estos métodos pueden tener en cuenta un rango pequeño de reacciones químicas. El trabajo presentado en esta tesis propone una solución a estos problemas mediante un método de trayectoria de partículas. El método es eficiente y capaz de simular cadenas y redes de degradación en sistemas heterogéneos con porosidad múltiples. El método se basa en el desarrollo de probabilidades de transición que describen las probabilidades de que las partículas que pertenecen a un estado determinado (producto químico y región móvil / inmóvil) en un momento dado se transformará en otro estado en un momento posterior. El método se utiliza para caracterizar el riesgo para la salud humana que representan las mezclas de degradación en medios porosos altamente heterogéneos derivados de focos de contaminación complejos. En particular, se investiga la interacción entre la heterogeneidad, la conectividad, el modo de inyección de los contaminantes y su toxicidad química con respecto a la caracterización probabilística del riesgo para la salud humana. Los resultados indican las condiciones mediante las cuales las vías de flujo preferencial pueden favorecer la reducción del riesgo para la salud humana. La dependencia de la conectividad con el riego se demuestra que no es nada trivial cuando se trata de mezclas de compuestos químicos. Esta no trivialidad es el resultado de la interacción entre la heterogeneidad del acuífero y la toxicidad de los compuestos químicos. Para cuantificar el efecto conjunto de la conectividad y la toxicidad en el riesgo para la salud, se propone un número de Damköhler nuevo que tiene en cuenta la toxicidad. Además, el riesgo también se caracteriza en términos estadísticos mediante momentos de bajo orden y funciones de densidad de probabilidad. Los resultados también muestran que tanto la capacidad de degradación de zonas inmóviles como los modelos existentes de agotamiento del foco pueden desempeñar un papel muy significativo en el análisis espacio-temporal del riesgo. Este trabajo también muestra que la eficiencia del foco de contaminación para concentrar el flujo puede tener un efecto beneficioso sobre el riesgo. El riesgo total de hecho tiende a disminuir para eficiencias grandes debido a la disminución consecuente en tiempos de viaje cerca del foco de contaminación, limitando la producción de productos de degradación más tóxicos.
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Kroner, Oliver. "The Alliance for Risk Assessment Dose-Response Framework: Practical Guidance for Risk Practitioners." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1314053236.
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Ågerstrand, Marlene. "From Science to Policy : Improving environmental risk assessment andmanagement of chemicals." Doctoral thesis, KTH, Filosofi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105225.
Анотація:
A complex process like risk assessment and the subsequent risk management decision makingshould be regularly evaluated, in order to assess the need to improve its workings. In this thesisthree related matters are addressed: evaluation of environmental risk management strategies,evaluation of environmental risk assessments, and how ecotoxicity data from the open scientificliterature can be used in a systematic way in regulatory risk assessments. It has resulted in thefollowing: a publically available database with ecotoxicity data for pharmaceuticals (Paper I); anevaluation and review of the Swedish Environmental Classification and Information System forpharmaceuticals (Papers II and III); a comparison of current reliability evaluation methods and areliability evaluation of ecotoxicity data (Paper IV); and an improved reliability and relevancereporting and evaluation scheme (Paper V).There are three overall conclusions from this thesis:(1) Ecotoxicity data from the open scientific literature is not used to the extent it could be inregulatory risk assessment of chemicals. Major reasons for this are that regulators prefer standarddata and that research studies in the open scientific literature can be reported in a way that affectstheir reliability and the user-friendliness. To enable the use of available data more efficiently actionsmust be taken by researchers, editors, and regulators. A more structured reliability and relevanceevaluation is needed to reach the goal of transparent, robust and predictable risk assessments.(2) A risk assessment is the result of the selected data and the selected methods used in theprocess. Therefore a transparent procedure, with clear justifications of choices made, is necessaryto enable external review. The risk assessments conducted within the Swedish EnvironmentalClassification and Information System for pharmaceuticals vary in their transparency and choice ofmethod. This could come to affect the credibility of the system since risk assessments are notalways consistent and guidelines are not always followed.(3) The Swedish Environmental Classification and Information System for pharmaceuticalscontribute, in its current form, to data availability and transparency but not to risk reduction. Thesystem has contributed to the general discussion about pharmaceuticals’ effect on the environmentand made data publicly available. However, to be an effective risk reduction tool this is not sufficient.QC 20121119
MistraPharma
Formas - Evaluation of the Swedish Environmental Classification and Information System for Pharmaceutcals.
15
Cao, Qiming. "Behaviour and Health Risk Assessment of Endocrine Disrupting Chemicals from Wastewater." Thesis, Griffith University, 2010. http://hdl.handle.net/10072/365513.
Анотація:
Water supply has become a social and economic issue in many countries as a result of global climate change, fast population growth, industrial and urban development. To address this issue, water recycling has been considered as a feasible technology to supplement the existing water supply. However, a major challenge with water recycling is the removal of harmful contaminants to meet drinking water guidelines and industrial requirements. Although various technologies can remove most contaminants efficiently, recent studies have shown that many endocrine disrupting chemicals (EDCs) can cause adverse health effects on wildlife species and humans at extremely low level. EDCs from wastewater treatment effluent are the major point source entering the aquatic environment. Consequently, various adverse health effects have been observed in wildlife species, such as population changes, reproductive abnormalities, imbalanced sex ratios and behaviour changes. Many adverse human health effects such as prostate cancer, breast cancer and birth defects have also been implicated with the exposure to EDCs. Thus, it is important to study these environmental contaminants. The main aim of this work was to develop an understanding of the behaviour and health risks of EDCs from wastewater. This work focused on four estrogens, estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2) and three phenolic compounds, nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA). The behaviour of a chemical in the environment is largely dependent on its physicochemical properties such as aqueous solubility (S) and octanol-water partition coefficient (Kow). Physicochemical properties, however, are related to chemical structures. A quantitative structure-property relationship (QSPR) evaluation was conducted by using measured physicochemical properties and calculated molecular descriptors. With single and multiple linear regression methods, good linear relationships were found between the measured log Kow values and three molecular descriptors: log FOSA (hydrophobic component of the total solvent accessible surface area), log FISA (hydrophilic component of the total solvent accessible surface area) and log PSA (Van de Waals surface area of polar nitrogen and oxygen atoms). Similar but weaker correlations were found between the measured log S values and each of the three molecular descriptors. The relationships can be used to obtain property values for various steroidal EDCs which may have potential environmental effects.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering
Science, Environment, Engineering and Technology
Full Text
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Gillespie, Annika Margaret. "Environmental toxicity of complex chemical mixtures." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1017.
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Shelton, Davis Anecia Delaine. "Transportation risk assessment for ethanol transport." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2032.
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Ding, Qian. "Regulatory tools for managing chemicals risk at the workplace." Doctoral thesis, KTH, Filosofi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127269.
Анотація:
This thesis focuses on exacerbating chemicals risk in workplaces under the background of rapid industrialization in developing countries. The overall aim is to investigate the development of regulatory tools which aim at minimizing the health risks from chemical substances in the workplace. The contents of the thesis are divided into three sections: the profile of occupational diseases in China (paper I), occupational exposure limits (paper II and III), and comparison between chemicals regulat ions in Europe and China (paper IV). Paper I presents an analysis of the development of occupational diseases in China between 2000 and 2010. The number of recorded cases of occupational diseases increased rapidly in China during this period and the majority of cases were attributable to dust and other chemicals exposures. Difficulties in diagnosis and inefficient surveillance are major impediments to the proper identification and mitigation of occupational diseases. Migrant workers are extremely vulnerable to occupational hazards. Paper II investigates the state of harmonization of OELs between twenty-five OEL systems in Europe and Asia. The majority of the investigated organizations declare themselves to have been influenced by the American Conference of Governmental Industrial Hygienists (ACGIH), and in many cases this can be empirically confirmed. However, large international differences still exist in substance selection and in the level of OELs among organizations. Paper III explores the setting of risk-based OELs on non-threshold carcinogens. Relatively few agencies set risk-based OELs. Differences exist in policy, both regarding the magnitude of risk considered as tolerable or acceptable and whether a general risk level or case-by-case substance-specific risk levels are determined. In regards to the level of the OELs both differences in science and policy contribute, and it was not possible to determine which has the larger influence. Paper III explores the setting of risk-based OELs on non-threshold carcinogens. Relatively few agencies set risk-based OELs. Differences exist in policy, both regarding the magnitude of risk considered as tolerable or acceptable and whether a general risk level or case-by-case substance-specific risk levels are determined. In regards to the level of the OELs both differences in science and policy contribute, and it was not possible to determine which has the larger influence. Paper IV systematically compares the regulation systems for chemicals in the EU and China in terms of substances covered, requirement on information, risk assessment and risk management. It shows that the European and Chinese chemicals legislations are remarkably similar.The differences are larger in terms of substance coverage and data requirements than in terms of risk assessment and management. Substitution of hazardous substances is driven more by updates of the EU regulatory system than of the Chinese system.QC 20130830
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Gabrielson, Jenny. "Assessing the toxic impact of chemicals using bacteria /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-143-1/.
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Nordberg, Anna. "Priority setting strategies for regulatory testing of industrial chemicals." Licentiate thesis, Stockholm : Philosophy and the History of Technology, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4554.
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Dorne, Jean Lou Christian Michel. "Human variability in kinetics for the major metabolic pathways : application to chemical risk assessment." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395575.
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Lillicrap, Adam. "Regulating the regulations and harmonizing the disharmonized : challenges and issues of regulatory environmental hazard and risk assessments of chemicals." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/25744.
Анотація:
The focus of this thesis is the regulatory aspects of environmental hazard and risk assessment of chemicals, with a particular emphasis on whether current regulatory requirements are sufficient for assessing the risks chemicals pose to the environment. Since the way that chemicals are currently regulated on a global, regional or national level is complex and challenging, it is not surprising that there are faults with the current system. Legislations and regulations, such as the European regulation on Registration, Evaluation, Authorisation and restrictions of Chemicals (REACH), specifically indicates that unnecessary testing should be avoided wherever possible. However, this has not been the case for all hazard evaluations and some substances may have been assessed unnecessarily, or incorrectly resulting in significant underestimation of the potential effects to the environment. The aim of this research was to identify the major pitfalls and flaws with how environmental risk assessments are being performed, and to find a more harmonious approach to properly ensure that chemicals are regulated more appropriately. Within this thesis, there are examples of ecotoxicity studies for substances that should have little or minimal environmental consequences but which have been required for regulatory reasons. Such an example highlighted in this thesis is the artificial sweetener sucralose or silica fume. Conversely, other substances which are likely to have severe adverse environmental impacts could have been authorised for use inappropriately without the additional research that was carried out. Examples of potentially harmful chemicals not being regulated sufficiently, detailed in this thesis, include benzoylurea pesticides, used in aquaculture, and novel antifoulant substances such as thiophenones used in industrial processes. The papers in this thesis indicate that there is a large disparity between how some substances are being regulated. In order to improve the current situation and to aid environmental risk assessors and regulatory authorities, integrated strategies have been proposed incorporating all available data to collectively inform on for example the bioaccumulative properties of a substance. In addition, recommendations for improving the risk assessment processes are discussed with the aim of better regulating chemicals and harmonizing future environmental risk assessments.
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Cundiff, Stephen J. "Screening Evaluation of Risk Assessment Tools that Assist in Exposure Assessment and Prioritization of Hazards in a Chemical Manufacturing Facility." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479820603595661.
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Scanferlato, Vjera Sostarec. "Environment risk assessment for toxic chemicals and genetically-engineered microorganisms : a microcosm approach /." Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-07282008-135357/.
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Gordon, Keith. "MACT Implementation at an Organic Chemical Manufacturing Facility: Human Health Risk Reduction." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1222.
Анотація:
Human health risk assessments are used by environmental regulatory agencies to determine risk from Hazardous Air Pollutants (HAPs). In this study, the Human Exposure Model (HEM-3) was used to compare the cancer and non-cancer inhalation health effects of a single organic chemical manufacturing facility in Geismar, Louisiana prior to and after Maximum Achievable Control Technologies (MACT) were implemented. The results indicate significant reductions in both cancer risk and non-cancer hazards. The analysis also indicated that the equivalent cancer risk reduction could have been achieved by addressing MACT in only one production process and one single pollutant (ethylene dichloride) within that process. This demonstrates the value that these risk assessments have at evaluating emissions at the facility level, and how they could be used in the control strategy decision making process.
26
Dettenmaier, Erik. "Measuring and Modeling of Plant Root Uptake of Organic Chemicals." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/18.
Анотація:
Determining the root uptake of xenobiotic organic chemicals into plants is critical for assessing the human and ecological health risks associated with the consumption of plants growing in contaminated environments. Root uptake of xenobiotic organics occurs passively in conjunction with transpiration and the transport from root to shoot is ultimately controlled by passage through one or more lipid root membranes. The transpiration stream concentration factor (TSCF), the ratio between the concentration of a chemical in the xylem to that in the solution used by the roots, is used to describe the relative ability of an organic chemical to be passively transported from root to shoot. However, relatively few experimental TSCF values exist due to the cost and the lack of regulatory requirements for generating such data. Where literature data exist for chemicals having more than one TSCF, the variability is often large due to the lack of standardized methods and difficulty in accounting for metabolism and volatilization losses occurring during the uptake experiments. Because of the scarcity of experimental values, estimated TSCFs are often used. Widely cited estimation approaches relating TSCF and the logarithm octanol/water partition coefficient (log KOW) suggest that only compounds that are in the intermediate lipophilicity range (log KOW = 2) will be taken up and translocated by plants. However, recent data for highly water soluble compounds such as 1,4-dioxane, MTBE, and sulfolane suggest that these estimation techniques should be critically reviewed. To re-evaluate the relationship between TSCF and log Kow, TSCFs were measured for 25 organic chemicals ranging in log KOW from -0.8 to 5 using an improved pressure chamber technique. The technique provides an approach for efficiently generating consistent plant uptake data. By using this data, a new mass transfer model relating TSCF and log KOW was developed that indicates that neutral, polar organic compounds are most likely taken up by plant roots and translocated to shoot tissue. An extensive review of literature TSCF studies supports the updated model.
27
Shabani, Shkelzen. "The Role of Chemical Senses in Predation, Risk Assessment, and Social Behavior of Spiny Lobsters." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/biology_diss/44.
Анотація:
Chemical senses play a critical role in predator-prey and social interactions of many animals. Predators often evoke adaptive escape responses by prey, one of which is the release of chemicals that induce adaptive avoidance behaviors from both predators and conspecifics. I explore the use of chemicals in predator-prey and social interactions, using a crustacean model system, the spiny lobster. As predators, spiny lobsters are opportunistic, polyphagous feeders, and they rely heavily on their chemical senses during feeding. Some of their potential prey deter attacks through chemical defenses that act through the spiny lobsters’ chemical senses. An example of this is sea hares, Aplysia californica, which secrete an ink when vigorously attacked by sympatric spiny lobsters, Panulirus interruptus. I show that that this ink defends sea hares from spiny lobsters through several mechanisms that include phagomimicry, sensory disruption, and deterrence, and that the ink’s efficacy is enhanced by its naturally high acidity. As prey, spiny lobsters rely heavily on their chemical senses to assess risk from predators. One way to assess risk of predation is through ‘alarm cues’, which are injury-related chemicals. I show that injured Caribbean spiny lobsters, Panulirus argus, release alarm cues in their hemolymph, and that nearby conspecifics detect these cues using olfaction. Hemolymph from conspecifics induces primarily alarm behavior in the form of retreat, sheltering, and suppression of appetitive responses. In contrast, hemolymph from heterospecifics, depending on phylogenetic relatedness, induces either mixed alarm and appetitive behaviors or primarily appetitive behaviors. Spiny lobsters also use chemical cues to assess risk during social interactions with conspecific. I show that spiny lobsters use urine-borne chemical signals and agonistic behaviors to communicate social status and that these chemical signals are detected exclusively by the olfactory pathway. Dominant animals increase urine release during social interactions, whereas subordinates do not. Experimental prevention of urine release during interactions causes an increase in agonism, but this increase is abolished when urine of dominants is reintroduced. My findings lay the foundation for neuroethological studies of risk-assessment systems mediated by intraspecific chemical cues.
28
Deveau, Michelle Leigh. "Exploration of Contextual Influences on the Incorporation of Chemical- and Scenario-Specific Data in the Derivation of Environmental Health and Occupational Exposure Limits for Chemicals." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42494.
Анотація:
Outputs of dose–response assessments can be used as benchmarks that help to identify the need for risk management measures to reduce population health risks associated with exposure to chemicals. Various approaches can be used to facilitate the incorporation of chemical- or scenario-specific data into dose–response analyses, as a means of replacing or influencing default assumptions and extrapolations. The goal of the first part of this thesis was to examine the evolution of approaches to the incorporation of chemical- and scenario-specific data in dose–response assessments in regulatory settings, and identify contextual factors that serve as barriers and facilitators to the use of approaches. A main focus of the investigation was on physiological modelling, which is the most commonly-used category of approaches enabling extrapolations that depart from default assumptions. Evaluations of the dose–response applications of physiological modelling in the peer-reviewed scientific literature and in regulatory reports were conducted. Similarities between the scientific literature databases and regulatory reports were observed with respect to the evolution of physiological modelling in dose–response assessments, notably related to the timing, quantity, and annual frequency of publications. These similarities indicate that a factor in the low dose–response application of physiological modelling, relative to the overall production of physiological models, is an absence of data. However, variability in adoption of physiological modelling in regulatory dose–response assessments was observed among—and even within—organizations faced with the same data, indicating that other factors influence regulatory uptake of physiological modelling. Analysis of a survey indicated that factors acting as barriers or facilitators to regulatory risk assessors’ incorporation of increasingly data-informed approaches originated in both external and internal contexts. The external context was composed of the regulatory environment, domestic and international alignment, availability of external expertise, background of peer reviewers and stakeholders, availability and accessibility of software and tools, and chemical-dependent factors. The internal context was influenced by problem formulation, time and financial resources, organizational and management support, and training. A conceptual framework demonstrating how these factors impact a risk assessor’s ability to incorporate chemical- and scenario-specific data in dose–response analysis was developed, and subsequently used to provide recommendations on actions that could be taken to increase regulatory adoption of increasingly data-informed approaches.
The second part of the thesis focused on the development of a knowledge translation tool designed to assist risk managers in the evaluation of dose–response analyses. The tool was focused on occupational exposure limits (OELs), and provides a guide to occupational hygienists in evaluating the relevance and reliability of individual OELs. When occupational hygienists are faced with multiple varying OELs for a chemical of interest, these evaluations can support the selection of the most appropriate OEL for a given situation. The usefulness of the tool was demonstrated for the selection of OELs for an OEL-rich compound (n-hexane), an OEL-poor compound (methamphetamine), and one additional compound (manganese). Such a tool can improve occupational hygienists’ understanding of the basis of OELs and the levels of protection afforded by each, which can contribute to more informed risk management decisions.
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Bensiali, Abdel K. "An expert system for the development of a health and safety policy/risk assessment in the plastics industry." Thesis, Aston University, 1988. http://publications.aston.ac.uk/10233/.
Анотація:
Health and safety policies are the cornerstone and a frame of reference for positive prevention of occupational accidents and diseases. The Health and Safety at Work, etc Act 1974 makes it a legal duty for employers to prepare and revise a written statement of a general policy with respect to the health and safety at work of employees as well as the organisation and arrangements for carrying out that policy. Despite their importance and the legal equipment to prepare them, health and safety policies have been found, in a large number of plastics processing companies (particularly small companies), to be poorly prepared, inadequately implemented and improperly monitored. An important cause of these inadequacies is the lack of necessary health and safety knowledge and expertise to prepare, implement and monitor policies. One possible way of remedying this problem is to investigate the feasibility of using computers to develop expert system programs to simulate the health and safety (HS) experts' task of preparing the policies and assisting companies implement and monitor them. Such programs use artificial intelligence (AI) techniques to solve this sort of problems which are heuristic in nature and require symbolic reasoning. Expert systems have been used successfully in a variety of fields such as medicine and engineering. An important phase in the feasibility of developmet of such systems is the engineering of knowledge which consists of identifying the knowledge required, eliciting, structuring and representing it in an appropriate computer programming language.
30
Hamidin, Nasrul. "Human Health Risk Assessment of Trace Chemicals in the Residential Environment Using Probabilistic Techniques." Thesis, Griffith University, 2011. http://hdl.handle.net/10072/367102.
Анотація:
Humans are exposed to a wide range of chemicals in the environment which may be hazardous to health. In this thesis two groups of chemicals from different mediums were investigated namely disinfection by-products (DBPs) in chlorinated drinking water and volatile aromatic hydrocarbons (VAHs) in residential indoor air.
The level of risk to human health was evaluated by health risk assessment using probabilistic techniques. In this thesis three factors were evaluated, (1) the exposure dose (EXPD) based on human exposure data (2) threshold Human Equivalent Dose (HED) based on test results on surrogate animals and (3) the dose-response using epidemiological data on adverse health responses as related to the threshold Lifetime Average Daily Dose (LADDH). The values obtained were plotted as cumulative probability (CP) relationships. The risk was characterized by three approach, (1) by comparison between EXPD with threshold HED and threshold LADDH, (2) by calculating the hazard quotient at 95/5 (HQ95/5) which was derived as the high exposure population from 95% from the cumulative probability of exposure doses (CP-EXPD) with the sensitive populations 5% from the human dose-response in terms of threshold cumulative probability Lifetime Average Daily Dose (CP-LADDH) and (3) by using hazard quotient by Monte Carlo techniques (HQMC) using Monte Carlo simulation via Crystal Ball software. Literature data on exposure concentrations from more than 10 countries and the adverse effects on animal laboratory experiments in terms of HED as well as human exposure and epidemiological studies in terms of LADDH were used in these evaluations.
With DBPs in chlorinated drinking water, EXPD was calculated from literature data from more than 10 countries and compared with threshold HED values from surrogate animals representing the threshold dose-response values for adverse effects. The highest human EXPD was lower than the threshold HED for TCM, BDCM, DBCM, TBM, DCAA and TCAA. All the threshold HED values were approximately 102 to 104 higher than EXPD at the 95% level. However, with the human epidemiology data, there was an overlap between the highest EXPD and the threshold LADDH representing the threshold dose-response values for adverse effects for TTHM, TCM, BDCM, DCAA and TCAA. This suggests that there are possible adverse health risks such as cancers and developmental effects on humans. The HQ95/5 values for TTHM, TCM and BDCM are 4.7, 5.7 and 9.2, respectively. This suggests that 5% of the human population has a high risk of adverse health effects. A similar result was also obtained for HQMC where the HQMC for TTHM (0.30>1), TCM (0.13>1) and DBCM (0.41>1) are higher than the unity value.
In the evaluation of VAHs from literature data, the comparison between the highest EXPD with the lowest threshold HED for adverse effects using surrogate animal data for ethylbenzene, mp-xylene, o-xylene and styrene shows no overlap. The lowest thresholds HED of these compounds are approximately 10 times higher than the EXPD at the 95% level. However, the maximum EXPD exceeded the threshold HED of benzene, toluene and naphthalene at the 60%, 94% and 30% respectively. Comparison was made using human exposure and human epidemiological data. The maximum EXPD exceeded the threshold LADDH derived from human health data for benzene and toluene only. This suggests that there are possible adverse health risks such as leukemia, developmental effect, aplastic anemia and chromosome aberration in blood. The HQ95/5 for benzene, toluene and styrene was 22.2, 1.2 and 0.3, respectively suggesting possible adverse effects in the 5% of the population.
In addition, the measurement of VAHs in the residential indoor air was also conducted for 32 houses in Brisbane. The total VAHs (TVAH) levels ranged between 2 to 137 g/m3 and were lower than the literature data on houses in Melbourne and Perth. The VAHs concentrations from indoor air of houses in Brisbane are higher than the outdoor ambient air. With an internal garage, the VAHs concentration is higher than the indoor air of the living room by 25 to 50% and may be a source of indoor VAHs due to the presence of motor vehicle in the garage. The age of the house was found to be positively related to VAHs concentrations in the house. The half-life of TVAH was found to be approximately 13 years.
The health risk assessment of VAHs in the indoor air of Brisbane houses was conducted using similar techniques to those used with the literature data for DBPs and VAHs. There was no overlap between maximum EXPD and thresholds HED dose-response data for all compounds except benzene and naphthalene. The lowest threshold HED for toluene, ethylbenzene, mp-xylene and o-xylene and styrene were found to be higher than the EXPD at 95% level by approximately 10 to 102. With benzene and naphthalene the maximum EXPD exceeded the threshold HED at the 95% and 85% respectively. An overlap was observed between maximum EXPD and threshold LADDH derived from human data for benzene only. The HQ95/5 for benzene, toluene and styrene are 2.7, 0.1 and 0.01 respectively. The HQ95/5 for benzene suggests 5% high exposure group in the human population has a high probability of risks of leukemia, developmental effect and aplastic anemia.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Engineering.
Science, Environment, Engineering and Technology
Full Text
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Oliveira, Rhaul. "Effects assessment of chemicals used in aquaculture." Doctoral thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/16297.
Анотація:
Doutoramento em BiologiaAquaculture provides food and income for millions of families worldwide being an activity with a high growth rate and with a strong potential for further expansion. Both producers and consumers are interested in a sustainable model of aquaculture development covering social, economic and environmental aspects. Such model implies to cope with the environmental impacts generated by aquacultures. The main objective of this work was to evaluate the use of chemicals applied in aquaculture farms and their harmful effects to aquatic organisms. Since more than 80% of global production of aquatic organisms is concentrated in Southwest Asia, special attention was given to the aquaculture in this region, particularly Thailand. Three different types of aquaculture scenarios were studied: shrimp farms and tilapia farms in cages and in earth ponds. Surveys and monitoring campaigns were conducted in several farms and the fate, use and application patterns of chemicals were identified. In cage farms the results indicated overuse/misuse of antibiotics, in shrimp farms the major group of chemicals used were disinfectants whereas in earth pond farms 1,7α-methyltestosterone (MT) was the most used. The results from the monitoring campaigns showed that the excessive use of chemicals was correlated to contamination of the surrounding environment namely with the antibiotics oxytetracycline (OTC) and enrofloxacin (ENR) in the cage farms, and with MT in the earth pond farms. In the laboratory, ecotoxicity assays were performed with antibiotics, disinfectants and pesticides using organisms belonging to different trophic levels. The disinfectants benzalkonium chloride (BKC), chlorhexidine gluconate (ChD) and glutaraldehyde (GA) were tested. BKC and ChD demonstrated to be very toxic to primary and secondary consumers. Moreover, an approach based on the species sensitivity distributions (SSD) was used to estimate the hazardous concentrations for 5 and 50 % of the species after BKC and GA exposure highlighting the sensitivity of primary producers to BKC exposure (HC5 = 10.8 μg/l). In the case of GA, different trophic levels showed similar sensitivities and a general HC5 = 300 μg/l was obtained. Additionally, a probabilistic environmental risk assessment was performed indicating a PAF (potentially affected fraction) of species > 5% for adverse effects of BKC in effluents and surface water. Concerning pesticides, both trichlorfon (TCF) and ivermectin (IVM) were studied. TCF showed to be extremely toxic to daphnids (48h- LC50 = 0.29 μg/l) and affected the acetilcolinesterase activity in D. magna and D rerio. IVM showed to be acutely toxic to D. rerio life stages (96h-LC50 = 18.5 μg/l for juveniles) and affected their development and biomarkers. In chronic exposures, IVM led to changes in the behaviour and growth of D. rerio juveniles (21d-LOEC < 0.25 μg/l). The antibiotics amoxicillin and OTC were not acutely toxic to aquatic organisms but both induced oxidative stress related enzymes of adults and embryos of D. rerio. Globally, most of the tested chemicals showed to compromise at least a particular group of organisms or sub-lethal parameters, requiring further long term studies so that the environmental risk assessment of these compounds can be refined. Lethal and sub lethal effects obtained to non-target organisms suggest a potential biodiversity loss in the aquatic ecosystems which might, thus, compromise the services provided by the ecosystems in a near future. Since the aquaculture relies directly on these services (e.g. high water quality) to succeed, there is an urgent need of control/education measures both in the use of chemicals in aquaculture and monitoring/mitigation of adverse impacts in natural ecosystems.
A aquacultura fornece sustento para milhões de famílias, sendo uma actividade em crescimento e com um forte potencial de expansão em todo o mundo. Há um interesse por parte de produtores e consumidores em desenvolver modelos sustentáveis de aquacultura abrangendo aspectos sociais, económicos e ambientais. Tais modelos implicam lidar com os impactos ambientais gerados pela aquacultura. O principal objectivo deste trabalho foi estudar o uso de produtos químicos usados nas aquaculturas e avaliar os seus efeitos nocivos para organismos aquáticos. Uma vez que mais de 80% da produção mundial de organismos aquáticos está concentrada no sudoeste da Ásia, foi dada especial atenção à aquacultura nessa região, particularmente na Tailândia. Três diferentes cenários foram considerados: aquaculturas de camarão, aquaculturas de tilápias cultivadas em gaiolas e em tanques escavados no solo. Em cada tipo foram realizados inquéritos e campanhas de monitoramento em várias aquaculturas nas quais foram averiguados o uso, destino e forma de aplicação de químicos. Os resultados indicaram o uso excessivo/inapropriado de alguns compostos, nomeadamente de antibióticos (em aquaculturas em gaiolas), de desinfectantes (em aquaculturas de camarão) e de 1,7α-metiltestosterona (MT) (em aquacultura de tilápias em tanques escavados). Os resultados das campanhas de monitorização mostraram que o uso excessivo de produtos químicos resulta na contaminação do meio ambiente com antibióticos (oxitetraciclina (OTC) e enrofloxacina (ENR)) nas aquaculturas em gaiola, e com MT nas aquaculturas de tilápias em tanques escavados. No laboratório, foram realizados ensaios de ecotoxicidade com antibióticos, desinfectantes e pesticidas usando organismos modelo pertencentes a diferentes níveis tróficos. Foram testados os desinfectantes, cloreto de benzalcónio (BKC), gluconato de clorexidina, e glutaraldeído (GA) sendo que os dois primeiros demonstraram ser muito tóxico para consumidores primários e secundários. Para uma análise integrada foi utilizada uma abordagem baseada nas distribuições de sensibilidade das espécies (DSE) com a qual se estimaram as concentrações perigosas (CP) para 5% e 50% das espécies após e exposição ao BKC e GA. O grupo dos produtores primários foi o grupo mais sensível à exposição ao BKC com CP5% = 10,8 μg/l enquanto para GA não foram encontradas diferenças de sensibilidade entre os grupos tróficos e, assim sendo, um valor geral de CP5% = 300 μg/l foi obtido. Além disso, uma análise probabilística dos riscos ambientais indicou uma fracção de espécies potencialmente afectada (FAPE) pelo BKC > 5% em efluentes e águas superficiais. Os pesticidas estudados foram o trichlorfon (TCF) e a ivermectina (IVM). O TCF foi extremamente tóxico para dafnídeos (48h-LC50 = 0,29 μg/l) e afectou também a actividade de acetilcolinesterase em D. magna e D. rerio. A IVM foi tóxica para adultos, juvenis e embriões de D. rerio (96h- CL50 = 18,5 μg/l para os juvenis) afectando o seu desenvolvimento e actividade de biomarcadores. Em exposições crónicas, IVM causou alterações no comportamento e crescimento em D. rerio juvenis (21d-LOEC <0,25 μg/l). Os antibióticos amoxicilina e OTC apresentam baixa toxidade para os organismos aquáticos, mas ambos induziram enzimas relacionadas estresse oxidativo em adultos e embriões de D. rerio. Em geral, a maioria dos químicos testados apresentaram toxicidade para algum grupo de organismo da cadeia trófica ou tiveram efeito a nível de parâmetros sub-letais, sendo portanto recomendados estudos de exposição crónica para que se possa refinar a avaliação de risco ambiental destes compostos. Os efeitos letais e sub-letais observados nos organismos não-alvo sugerem que pode haver uma perda da biodiversidade nos ecossistemas aquáticos, e assim, comprometer os serviços prestados pelos ecossistemas num futuro próximo. Sendo o sucesso da aquacultura dependente directo destes serviços (por exemplo, água de alta qualidade), há uma necessidade urgente de medidas de controlo/educação, tanto no uso de produtos químicos na aquacultura e monitoramento/mitigação dos impactos negativos destes nos ecossistemas naturais.
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Khanna, Vikas. "Environmental and Risk Assessment at Multiple Scales with Application to Emerging Nanotechnologies." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1245316311.
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Ma, Yukun. "Human health risk of toxic chemical pollutants generated from traffic and land use activities." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/92724/1/Yukun_Ma_Thesis.pdf.
Анотація:
The research project developed a quantitative approach to assess the risk to human health from heavy metals and polycyclic aromatic hydrocarbons in urban stormwater based on traffic and land use factors. The research outcomes are expected to strengthen the scientifically robust management and reuse of urban stormwater. The innovative methodology developed can be applied to evaluate human health risk in relation to toxic chemical pollutants in urban stormwater runoff and for the development of effective risk mitigation strategies.
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Schirinzi, Gabriella Francesca. "Chemical and ecotoxicological assessment of microplastics and emerging risks in the coastal environments." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/669139.
Анотація:
In recent decades, global plastics production and consumption have continued to increase. Although many policy strategies on waste prevention and recycling have been implemented, much of the plastic waste is dispersed in nature. In general, the presence of waste in the aquatic environment is a serious environmental problem, well known as marine waste, and is responsible for environmental, economic, health and aesthetic problems at the ocean and regional level and the dominant category of waste is plastics. Due to their chemical persistence, buoyancy and increased sources, plastic objects and their fragments (known as "microplastics" (MPLs) and "nanoplastics" (NPLs)) are omnipresent in the marine environment, especially in closed basins such as the Mediterranean Sea. Nowadays, given the increasing levels of plastic pollution in marine environments, MPL/NPL are considered emerging pollutants that can pose a serious threat to marine ecology and human health. Despite constant scientific progress, large gaps in knowledge about the fate, distribution, behaviour and effects of MPLs/NPLs have not yet been filled.
In this context, this thesis aimed to expand knowledge on plastic pollution in coastal environments. In particular, the first part of the study focused on the river transport of plastics and the fate and behaviour of MPLs/NPLs in estuaries and coastal waters. The results of one year of visual observations of floating anthropogenic macro-litters (> 2.5 cm) of the Llobregat and Besòs Rivers showed that the Barcelona metropolitan area contributes substantially to marine pollution. Large quantities of plastic (mainly single-use goods) were transported from these rivers to the western Mediterranean Sea. Given the significant contribution of plastic waste from rivers, valuable information can be obtained by assessing the spatial distribution of MPLs/NPLs in estuarine environments. To perform these studies, several analytical techniques based on mass spectrometry (MALDI-TOF/MS, DART-MS, and LC-APPI-HRMS) were compared for the quantitative analysis of MPLs/NPLs in water samples. The best results in terms of sensitivity were obtained with dimensional exclusion-LC coupled with APPI-QExactive. Consequently, a new LC-HRMS method was optimized, validated and finally applied to assess the presence of PS in natural water samples from the Ebro Delta (Catalonia, Spain). The results reported the highest concentrations along the river near urban areas and in the bay where important commercial fishing activities are established. In addition to plastic pollution, estuaries can be highly contaminated with persistent organic pollutants, especially from wastewater. Since MPLs may also be responsible for the transport and distribution of pollutants, the absorption behaviour of MPLs with perfluoroalkylated substances (PFASs) in freshwater and seawater has been assessed. An increase in adsorption capacity was observed in this order PS>PS-COOH>PE.
As demonstrated by these results, the plastic pollution of coastal ecosystems, from macro to nano, is a real problem that can lead to serious damage to both nature and society. To protect the coastal environment, its productivity and humans, it is necessary to assess the ecotoxicological impacts on marine organisms and human health. In this regard, a new digestion approach has been developed to determine the presence of MPLs in the gastrointestinal tracts of a sentinel species in the Western Mediterranean. The high frequency of plastics and the types of polymers reported in this study confirmed the negative impacts of local fishing gear. Although the ingestion of MPLs by marine organisms is a widely recognised effect of marine plastic waste, very limited data are available on the impact of MPLs, and especially NPLs, on human health. Therefore, cytotoxic effects at the cellular level after exposure to moderate concentrations of PS and PE particles of nanometric size have been assessed. Significant results were reported only at high concentrations of PS.
In conclusion, the work presented in this thesis has successfully filled some of the various gaps in knowledge about plastic pollution and its effects. In the future, further tools should be promoted to facilitate the overall analysis of smaller MPLs, including NPLs.Los plásticos han desempeñado un papel importante en el desarrollo tecnológico e industrial, mejorando la calidad de la vida humana, pero, el uso excesivo y mala gestión de los desechos han dado lugar a la acumulación de residuos plásticos en el medio ambiente. Debido a su persistencia, los desechos plásticos se encuentran presentes en diferentes compartimentos ambientales como ya ha sido señalado en varios estudios, donde la mayor preocupación se centra en las partículas de tamaño más pequeño. Hoy en día, los micro(nano)plásticos se consideran contaminantes peligrosos que pueden causar graves daños al medio ambiente y la salud humana. Es por ello que se debe profundizar en la evaluación química y ecotoxicológica de los micro(nano)plásticos y los riesgos emergentes. La investigación científica ha promovido numerosas iniciativas para evaluar la presencia, destino e impacto ambiental de estos contaminantes en el medio acuático, especialmente en los medios marinos. En este contexto, los objetivos generales de esta tesis doctoral se enfocaron en estudios integrados de la presencia y destino de la contaminación plástica en el medio ambiente costero, especialmente en el transporte fluvial de macroplásticos en la zona de Barcelona y el destino/comportamiento de las micro(nano)partículas de plástico en las aguas estuarinas y costeras del noroeste del Mar Mediterráneo. Para ello, se desarrollaron métodos analíticos para cuantificar e identificar el comportamiento de estos compuestos y sus co-contaminantes en el medio ambiente. Los resultados demostraron una contribución significativa de desechos plásticos provenientes de los ríos. En particular, para el análisis de micro(nano)plásticos en agua, se desarrolló un método con exclusión dimensional-LC acoplada con APPI-QExactive que permitió cuantificar la presencia de poliestireno (PS) en muestras de agua del Delta del Ebro (Cataluña, España). Posteriormente, se realizó un estudio de adsorción de sustancias perfluoroalquiladas en la superficie de los microplásticos donde se observó un aumento de la capacidad de adsorción de PS>PS-COOH> polietileno. Por último, se evaluaron las consecuencias ecotoxicológicas de los micro(nano)plásticos en el medio ambiente y la salud humana. Se confirmó una alta frecuencia de plásticos en una especie centinela del Mediterráneo, producto de los aparejos de pesca locales. Finalmente, los efectos citotóxicos de los PS-nanoplásticos han sido comprobados por estudios toxicológicos en células humanas.
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Rodríguez, Pinhao Miessner Diego. "Production of AAV vectors for gene therapy : a cost-effectiveness and risk assessment." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104215.
Анотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Chemical Engineering, 2016. In conjunction with the Leaders for Global Operations Program at MIT.Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, 2016. In conjunction with the Leaders for Global Operations Program at MIT.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 51-56).
Gene therapy is a promising modality for the potential treatment of rare Mendelian diseases. To date a number of high profile proof-of-concept studies within the industry have demonstrated the significant disease-correcting promise of this therapeutic strategy. One of the major hurdles that remains for the commercialization of gene therapies is the lack of efficient manufacturing capabilities for the production of clinical-grade drug substance/drug product. The primary goals for this project were to decrease the biological contamination and cross-contamination risk associated with the biologic manufacturing process for viral gene therapy vectors and to adjust the process in order to optimize commercial profit. The project also included documenting the different existing processes for AAV production and developing a competitive analysis using information from ongoing clinical trials in the industry pipeline. The following process design steps were followed in order to fulfill the project objectives: (1) Define product specifications, analytical needs and market size, (2) Select production platform/process, (3) Collect data and create process flow diagram, (4) Perform material and energy balances, (5) Calculate costs: equipment and consumables, (6) Model the process in a spreadsheet, (7) Carry out sensitivity analyses, (8) Assess cost-effectiveness and risk, and (9) Develop recommendations. Five different AAV production platforms were identified and an AAV gene therapy landscape was generated. Also, the current process that Pfizer is planning to use was documented and an initial market sizing was performed. Finally, all the data necessary to model the process was collected and the cost-effectiveness and biological contamination and cross-contamination risk assessment were completed. This project confirmed that the use of a scalable line of single-use high cell density bioreactors for the production of AAV is cost-effective. This implies that sufficient AAV quantities can be manufactured for preclinical and clinical trials, using the process developed by Pfizer.
by Diego Rodríguez Pinhao Miessner.
S.M.
M.B.A.
36
Jackson, Benjamin W. "The GREAT-ER model as a tool for chemical risk assessment and management for Chinese river catchments." Thesis, Lancaster University, 2018. http://eprints.lancs.ac.uk/126264/.
Анотація:
The Chinese government has introduced a range of policies with the aim to improve freshwater quality to safe levels for both humans and ecosystem function. These policies form an important part of sustainable economic development. An important component of the improvement in surface water quality is to assess and reduce the risk from organic chemicals. The development of reliable predictive tools is therefore required which can be used for the purpose of chemical risk assessment and catchment management. The catchment scale Geo-referenced Regional Exposure Assessment Tool for European Rivers (GREAT-ER) model was developed for this purpose. Its application in China would represent a valuable water quality management tool. However, the data requirements for the parameterization of GREAT-ER are difficult to meet, especially in countries with limited data accessibility such as China. A methodology has been developed to facilitate the use of the GREAT-ER model in any catchment in China. Key methodological contributions include an approach to locate sewage treatment works (STW), estimate population served and to estimate the distribution and magnitude of untreated emissions. Low-flow statistics were estimated by means of regional regression. The GREAT-ER model was applied to the East river catchment for the chemicals Triclosan (TCS), Triclocarban (TCC), Estrone (E1) and 17β-estradiol (E2). As part of the study, a sampling campaign was conducted in January 2016 to collect water samples from sites within the East river catchment; samples were subsequently analysed to determine the concentration of target chemicals. These data, along with data obtained from collaborators collected in December 2008, were used to estimate the accuracy of the model. Overall, the model performed well for E1 and E2. However, there were some significant errors in the model’s estimation for the concentration of TCC and TCS. This included a number of remote rural subcatchments, which may be a reflection of the affordability of personal care products to the rural population. These, and other factors, were explored during validation of the model. A risk assessment was performed for the four chemicals for the years 2016 and 2020. In 2016, the model estimated that TCC would not exceed the predicted no effect concentration (PNEC) anywhere in the catchment, however, in 2020 the PNEC was exceeded for 3 stretches, each downstream of major STWs. The model estimated that the concentrations of E1 and E2 in 2016 would exceed PNEC values in stretches largely confined to the heavily urbanised Shenzhen catchment, but also isolated minor stretches located downstream of population centres. In 2020, the number of stretches exceeding the PNEC threshold reduced for areas with improved wastewater treatment infrastructure, but overall, the area that exceeded the PNEC for E1 and E2 was estimated to expand. TCS posed a high risk to the catchment in 2016, with the model predicting the PNEC to be exceeded throughout much of the catchment. In 2020, it was estimated that the same stretches would exceed the PNEC for TCS, but concentrations would be considerably higher overall. A series of catchment management scenarios were then utilised, such as increasing STW removal efficiency and the expansion of STW connectivity. These infrastructure developments were found to be effective for E1 and E2, but not so for TCS.
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Jayarathne, Ayomi L. "Transformation of physical and chemical properties of metals built-up on urban road surfaces." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/122560/1/Ayomi_Jayarathne_Thesis.pdf.
Анотація:
This project was a step forward in developing new knowledge relating to the influence of transformations that metals undergo during dry weather periods whilst they are deposited on urban road surfaces, on stormwater quality. Further, a new risk assessment method was proposed based on the transformation characteristics of metals. The generic outcomes of this study are expected to contribute to the implementation of appropriate stormwater pollution mitigation strategies to enhance stormwater reuse.
38
Malaj, Egina [Verfasser]. "Safeguarding freshwater organisms from chemicals: from the application of evolutionary concepts in ecotoxicology to large-scale risk assessment of chemicals / Egina Malaj." Landau : Universitätsbibliothek Landau, 2015. http://d-nb.info/1068193883/34.
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Villa, Valeria <1988>. "Extension of Quantitative Risk Assessment to the Analysis of External Hazard Factors in the Chemical and Process Industry." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7945/1/Villa_Valeria_Tesi.pdf.
Анотація:
The PhD research project is aimed at developing and applying an innovative framework toward Risk Assessment of cascading events within the chemical and process industry, addressing both domino and security-based events.
Cascading events are catastrophic accidents, triggered by external hazard factors, including safety-based (i.e., domino) and security-based events. In the chemical industry domain, barriers provide a crucial role for the prevention, control and mitigation of cascading events. Therefore, it is necessary to apply innovative techniques, aimed at the evaluation of barriers technical performance and at their optimal economic allocation, to be inserted within Quantitative Risk Assessment (i.e., QRA).
Concerning barriers technical performance, the research activity is aimed at applying Bayesian Networks to safety barriers performance assessment, regarding domino events. Starting from a conventional approach, preliminary applications have been aimed at implementing a Bayesian approach to barriers performance assessment concerning major accidents. Therefore, the approach has been extended to domino accident analysis, in purpose to evaluate the effect of barriers introduction within modelling. The case studies demonstrated that the application of a Bayesian approach provides a very accurate barriers performance assessment within QRA, with reference to external hazard factors driven accidents (i.e., domino events), offering a realistic risk picture.
Concerning barriers optimal economic allocation, the research activity is aimed at developing and applying an original economic model for the prevention of security-based cascading events. The model includes security upgrades performance and costs assessment, evaluation of benefits and definition of threat and vulnerability probabilities. The application of economic techniques, by means of cost-benefit and cost-effectiveness analyses, enables barriers optimal allocation within budgets constraints. Validation of the model is provided by application to relevant case studies. Therefore, the model enables defining rational criteria for barriers optimal selection and allocation and its outputs support the inclusion of security hazards within QRA, and related decision-making.
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TANAKA, TAKU. "PROBABILISTIC AND FULL-CHAIN RISK ASSESSMENT OF THE CHEMICAL ACCUMULATION ON HUMAN BODY USING AN INTEGRATED MODELLING TOOL." Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150169.
Анотація:
Mathematical models have been developed to address diverse issues. Especially environmental multimedia models are now well recognized as useful tools for environmental and health risk assessment and management. This dissertation consists of three main pillars: (i) the introduction of the newly developed integrated modelling tool (2-FUN tool) that deals with environmental and health risk assessment, (ii) the investigation of statistical approaches to derive density functions (PDFs) of input parameters of interest, and (iii) the application of the 2-FUN tool for a designed case study.
Chapter 1 presents general roles of mathematical models for health and environmental risk assessment of chemicals, the importance to consider parametric uncertainty, and the extensive review on existing modelling methodologies. At the end of the model review, main features of the 2-FUN tool are pointed out as follows: (i) Its capability to conduct a full-chain risk assessment on a common system, which allows linking the simulation of chemical fate in the environmental media, multiple pathways of exposure, and the detailed analysis for multiple effects in different target tissues in human body, (ii) it contains a wide range of methods for sensitivity and uncertainty analyses, and (iii) it can be user-friendly because of its effective graphical simulation interface and its flexibility, which facilitates users to design scenarios for target regions and arrange the tool on their own ways.
The conceptual and theoretical aspects of the 2-FUN tool are summarized in Chapter 2. The focus of Chapter 3 is set at the detailed presentation of two advanced statistical approaches to derive probabilistic density function (PDF) for the two parameters used in the freshwater compartment of the 2-FUN tool: the settling velocity of particles that is a driving factor influencing the transfer of particles at the water-sediment interface in fresh-water system, and the fish bioconcentration factor (BCF) for metal that represents the accumulation of a given chemical in organisms arising by water uptake.
Finally, Chapter 4 depicts how the 2-FUN tool can be applied based on a designed case study and shows the feasibility of the integrated modelling approach to couple an environmental multimedia and a PBPK models, considering multi-exposure pathways, and thus the potential applicability of the 2-FUN tool for health risk assessment.
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Olujimi, Olanrewaju Olusoji. "The concentrations, distribution and health risk assessment of suspected endocrine disrupting chemicals (phenols, phthalates and heavy metals) in freshwater systems of Cape Town, South Africa." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/2009.
Анотація:
Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2012.Environmental pollution with persistent organic chemicals and inorganic trace metals is an increasingly important issue. Recently, a variety of chemicals are introduced in a very large scale on the surface water network. The main pathway of these pollutants into the environment was identified as wastewater treatment plants (WWTPs). The extended use of chemicals in many product formulations and insufficient WWTPs has lead to an increase in the levels of the detected micro-pollutants wastewater effluents. The majority of these compounds are characterized by a rather poor biodegradability. A large spectrum of pollutants present in waste as traces has been reported to exert adverse effects on human and wildlife. Even though compounds are found in wastewater in a very small amount, they may have the undesirable capability of initiating health effect on various high forms of life. This survey constitutes the first study in the City of Cape Town to report data for a variety of priority substances (phenols and phthalate esters) in WWTP effluents and receiving rivers. These results are of critical importance since the data generated are used to generate potential health risk associated with both the organic and inorganic compounds analyzed.
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Pettersson-Strömbäck, Anita. "Chemical exposure in the work place : mental models of workers and experts." Doctoral thesis, Umeå universitet, Yrkes- och miljömedicin, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1646.
Анотація:
Many workers are daily exposed to chemical risks in their work place that has to be assessed and controlled. Due to exposure variability, repeated and random measurements should be conducted for valid estimates of the average exposure. Traditionally, experts such as safety engineers, work environment inspectors, and occupational hygienists, have performed the measurements. In self assessment of exposure (SAE), the workers perform unsupervised exposure measurements of chemical agents. This thesis studies a prerequisite for SAE, i.e. the workers’ mental models of chemical exposure. Further, the workers’ mental models are contrasted with experts’ reasons and decision criteria for measurement. Both qualitative and quantitative data generated from three studies (Paper I, II, and III) were used to describe the workers’ mental model of chemical exposure. SAE was introduced to workers in three different industries; transports (benzene), sawmill industry (monoterpenes), and reinforced plastic industry (styrene). By interviews, qualitative data were collected on the workers’ interpretation of measurement results and preventive actions. To evaluate the validity of worker measurement, the measurements were compared with expert measurements. The association between each worker’s number of performed measurement and mean level and variability in exposure concentrations was calculated. Mean absolute percent/forecast error (MAPE) was used to assess whether the workers’ decision models were in accordance with a coherence or correspondence model. In Paper IV, experts (safety engineers, work environment inspectors, and occupational hygienists) were interviewed to elucidate their mental models about the triggers and decision criteria for exposure measurements. The results indicate that the workers’ measurement results were in agreement with experts’. However, the measurement results were not a strong enough signal to induce workers to take preventive actions and sustained exposure measurements even if the measurement result were close to the occupational exposure limit. The fit was best for the median model, indicating that the workers’ mental models for interpretation of measurement data can best be described by the coherence theory rather than by the correspondence theory. The workers seemed to mentally reduce the variation in the exposure to a measure of central tendency (the median), and underestimated the average exposure level. The experts were found to directly take preventive actions instead of performing exposure measurements. When they performed exposure measurements, a worst case sampling strategy was most common. An important trigger for measurement for the experts was “request from the employer” (safety engineers), “legal demands” (work environment inspectors), and “symptoms among workers” (occupational hygienists). When there was a trigger, all experts mentioned expectations of high exposure level as a decision criterion for measurements. In conclusion, the studies suggest that workers’ mental interpretation model is best described in terms of a coherence model rather than a model of correspondence. The workers reduced the variation mentally in favor of an estimate of average exposure (median), which may imply that they underestimate short-term, high exposure health risks. A consequence is that interpretation of measurements such as SAE cannot be given to the individual worker without some support, e.g. from an expert. However, experts often chose to directly take preventive actions, without measuring the exposure. The results indicate that also the experts need support e.g. from the legal system if exposure measurements are to be done.
43
Sand, Salomon. "Dose-response modeling : evaluation, application, and development of procedures for benchmark dose analysis in health risk assessment of chemical substances /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-420-1/.
44
Beck, Christine P. "Potential Effects of Chemical Contamination on South Florida Bonefish Albula vulpes." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2980.
Анотація:
An ecological risk assessment was conducted on the risk to fish of chemical contaminants detected in the habitat of Albula vulpes in South Florida, to evaluate whether contaminants may be a driver of declines in the recreational bonefish fishery. All available contaminant detection data from Biscayne Bay, Florida Bay, and the Florida Keys were compared to federal and state guidelines for aquatic health to identify Contaminants of Potential Ecological Concern (COPECS). For these COPECs, species sensitivity distributions were constructed and compared with recent detections at the 90th centile of exposure. Copper in Biscayne Bay was identified as the highest risk of acute and chronic effects to fish, followed by a risk of chronic effects from both the recently phased-out pesticide endosulfan in Florida Bay, and the pharmaceutical hormone estrone in the Florida Keys.
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Rybacka, Aleksandra. "A step forward in using QSARs for regulatory hazard and exposure assessment of chemicals." Doctoral thesis, Umeå universitet, Kemiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-120223.
Анотація:
According to the REACH regulation chemicals produced or imported to the European Union need to be assessed to manage the risk of potential hazard to human health and the environment. An increasing number of chemicals in commerce prompts the need for utilizing faster and cheaper alternative methods for this assessment, such as quantitative structure-activity or property relationships (QSARs or QSPRs). QSARs and QSPRs are models that seek correlation between data on chemicals molecular structure and a specific activity or property, such as environmental fate characteristics and (eco)toxicological effects. The aim of this thesis was to evaluate and develop models for the hazard assessment of industrial chemicals and the exposure assessment of pharmaceuticals. In focus were the identification of chemicals potentially demonstrating carcinogenic (C), mutagenic (M), or reprotoxic (R) effects, and endocrine disruption, the importance of metabolism in hazard identification, and the understanding of adsorption of ionisable chemicals to sludge with implications to the fate of pharmaceuticals in waste water treatment plants (WWTPs). Also, issues related to QSARs including consensus modelling, applicability domain, and ionisation of input structures were addressed. The main findings presented herein are as follows: QSARs were successful in identifying almost all carcinogens and most mutagens but worse in predicting chemicals toxic to reproduction. Metabolic activation is a key event in the identification of potentially hazardous chemicals, particularly for chemicals demonstrating estrogen (E) and transthyretin (T) related alterations of the endocrine system, but also for mutagens. The accuracy of currently available metabolism simulators is rather low for industrial chemicals. However, when combined with QSARs, the tool was found useful in identifying chemicals that demonstrated E- and T- related effects in vivo. We recommend using a consensus approach in final judgement about a compound’s toxicity that is to combine QSAR derived data to reach a consensus prediction. That is particularly useful for models based on data of slightly different molecular events or species. QSAR models need to have well-defined applicability domains (AD) to ensure their reliability, which can be reached by e.g. the conformal prediction (CP) method. By providing confidence metrics CP allows a better control over predictive boundaries of QSAR models than other distance-based AD methods. Pharmaceuticals can interact with sewage sludge by different intermolecular forces for which also the ionisation state has an impact. Developed models showed that sorption of neutral and positively-charged pharmaceuticals was mainly hydrophobicity-driven but also impacted by Pi-Pi and dipole-dipole forces. In contrast, negatively-charged molecules predominantly interacted via covalent bonding and ion-ion, ion-dipole, and dipole-dipole forces. Using ionised structures in multivariate modelling of sorption to sludge did not improve the model performance for positively- and negatively charged species but we noted an improvement for neutral chemicals that may be due to a more correct description of zwitterions. Overall, the results provided insights on the current weaknesses and strengths of QSAR approaches in hazard and exposure assessment of chemicals. QSARs have a great potential to serve as commonly used tools in hazard identification to predict various responses demanded in chemical safety assessment. In combination with other tools they can provide fundaments for integrated testing strategies that gather and generate information about compound’s toxicity and provide insights of its potential hazard. The obtained results also show that QSARs can be utilized for pattern recognition that facilitates a better understanding of phenomena related to fate of chemicals in WWTP.Enligt kemikalielagstiftningen REACH måste kemikalier som produceras i eller importeras till Europeiska unionen riskbedömas avseende hälso- och miljöfara. Den ökande mängden kemikalier som används i samhället kräver snabbare och billigare alternativa riskbedömningsmetoder, såsom kvantitativa struktur-aktivitets- eller egenskapssamband (QSARs eller QSPRs). QSARs och QSPRs är datamodeller där samband söks korrelationer mellan data för kemikaliers struktur-relaterade egenskaper och t.ex. kemikaliers persistens eller (eko)toxiska effekter. Målet med den här avhandlingen var att utvärdera och utveckla modeller för riskbedömning av industri kemikalier och läkemedel för att studera hur QSARs/QSPRs kan förbättra riskbedömningsprocessen. Fokus i avhandlingen var utveckling av metoder för identifiering av potentiellt cancerframkallande (C), mutagena (M), eller reproduktionstoxiska (R) kemikalier, och endokrint aktiva kemikalier, att studera betydelsen av metabolism vid riskbedömning och att öka vår förståelse för joniserbara kemikaliers adsorption till avloppsslam. Avhandlingen behandlar även konsensusmodellering, beskrivning av modellers giltighet och betydelsen av jonisering för kemiska deskriptorer. De huvudsakliga resultaten som presenteras i avhandlingen är: QSAR-modeller identifierade nästan alla cancerframkallande ämnen och de flesta mutagener men var sämre på att identifiera reproduktionstoxiska kemikalier. Metabolisk aktivering är av stor betydelse vid identifikationen av potentiellt toxiska kemikalier, speciellt för kemikalier som påvisar östrogen- (E) och sköldkörtel-relaterade (T) förändringar av det endokrina systemet men även för mutagener. Träffsäkerheten för de tillgängliga metabolismsimulatorerna är ganska låg för industriella kemikalier men i kombination med QSARs så var verktyget användbart för identifikation av kemikalier som påvisade E- och T-relaterade effekter in vivo. Vi rekommenderar att använda konsensusmodellering vid in silico baserad bedömning av kemikaliers toxicitet, d.v.s. att skapa en sammanvägd förutsägelse baserat på flera QSAR-modeller. Det är speciellt användbart för modeller som baseras på data från delvis olika mekanismer eller arter. QSAR-modeller måste ha ett väldefinierat giltighetsområde (AD) för att garantera dess pålitlighet vilket kan uppnås med t.ex. conformal prediction (CP)-metoden. CP-metoden ger en bättre kontroll över prediktiva gränser hos QSAR-modeller än andra distansbaserade AD-metoder. Läkemedel kan interagera med avloppsslam genom olika intermolekylära krafter som även påverkas av joniseringstillståndet. Modellerna visade att adsorptionen av neutrala och positivt laddade läkemedel var huvudsakligen hydrofobicitetsdrivna men också påverkade av Pi-Pi- och dipol-dipol-krafter. Negativt laddade molekyler interagerade huvudsakligen med slam via kovalent bindning och jon-jon-, jon-dipol-, och dipol-dipol-krafter. Kemiska deskriptorer baserade på joniserade molekyler förbättrade inte prestandan för adsorptionsmodeller för positiva och negativa joner men vi noterade en förbättring av modeller för neutrala substanser som kan bero på en mer korrekt beskrivning av zwitterjoner. Sammanfattningsvis visade resultaten på QSAR-modellers styrkor och svagheter för användning som verkyg vid risk- och exponeringsbedömning av kemikalier. QSARs har stor potential för bred användning vid riskidentifiering och för att förutsäga en mängd olika responser som krävs vid riskbedömning av kemikalier. I kombination med andra verktyg kan QSARs förse oss med data för användning vid integrerade bedömningar där data sammanvägs från olika metoder. De erhållna resultaten visar också att QSARs kan användas för att bedöma och ge en bättre förståelse för kemikaliers öde i vattenreningsverk.
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Nadal, Lomas Martí. "Human health risk assessment of exposure to environmental pollutants in the chemical / petrochemical industrial area of Tarragona (Catalonia, Spain)." Doctoral thesis, Universitat Rovira i Virgili, 2005. http://hdl.handle.net/10803/8719.
Анотація:
Tesi: Human health risk assessment of exposure to environmental pollutants in the chemical/petrochemical industrial area of Tarragona (Catalonia, Spain).Autor: Martí Nadal
Resum:
Un dels complexos químics/ petroquímics més importants del sud d'Europa està ubicat a Tarragona. En els darrers anys, ha augmentat la preocupació pública envers els possibles efectes adversos que el complex industrial podria tenir per a la salut de la població resident a Tarragona. En resposta, el 2002 s'inicià un estudi per tal de determinar els nivells de diversos contaminants a l'àrea. En concret, es van recollir mostres de sòls i vegetació (bledes silvestres) en diversos punts dels Polígons Nord i Sud, així com del centre urbà de Tarragona i diversos barris residencials. Finalment, es van prendre mostres fora de l'àrea d'influència directa de les indústries (controls). En totes les mostres, es van determinar les concentracions d'arsènic (As), cadmi (Cd), crom (Cr), mercuri (Hg), manganès (Mn), plom (Pb) i vanadi (V). Per altra banda, també s'hi analitzaren els nivells de policlorodibenzo-p-dioxines i furans (PCDD/Fs), bifenils policlorats (PCBs), naftalens policlorats (PCNs) i hidrocarburs aromàtics policíclics (PAHs).
Els sòls recollits en el complex químic i les àrees urbana/residencial presentaren les concentracions més elevades per a tots els contaminants analitzats. La diferència respecte a les zones petroquímica i no contaminada fou significativa pel Cr, el V, els PCDD/Fs i els PCBs. No obstant, els nivells de tots els contaminants en sòl foren clarament menors a les concentracions màximes permeses en les legislació. Quant a les bledes, no es van trobar diferències significatives per a cap dels contaminants, llevat del V. En conseqüència, es podria considerar que Tarragona presenta un cert grau de contaminació per part d'aquest metall.
L'aplicació del mapa auto-organitzatiu de Kohonen (SOM) i l'anàlisi de components principals (PCA) permeté la identificació d'alguns punts del sud-oest del complex químic, i del centre urbà de Tarragona, pels seus alts nivells de contaminació. De fet, la presència d'una planta de producció de clor, així com el règim de vents predominant (mestral) i l'altura de les torxes i xemeneies de la refineria (facilitant la dispersió lluny del focus) serien una explicació raonable de les concentracions relativament més elevades de l'àrea química.
Les actuals concentracions de metalls pesants no suposen un augment rellevant dels riscos no cancerígens per a la població. No obstant, un cert nombre de casos de càncer podria derivar de la ingesta d'As (a causa dels baixos nivells d'As establerts per l'US EPA) i inhalació de Cr (ja que es va assumir que el Cr6+ era 1/6 del crom total). L'avaluació de riscos de l'exposició a PCDD/Fs es dugué a terme en funció del nivell socioeconòmic de la població. L'exposició directa suposa menys del 2% del total. Globalment, els habitants de les àrees residencials estan més exposats a les PCDD/Fs a causa de la ingesta dietètica. De tota manera, els riscos associats a aquesta exposició són assumibles.
Considerant les baixes concentracions de PAHs, es va estudiar la influència de la temperatura i la radiació solar en la fotodegradació de PAHs. S'observà que ambdues variables podrien tenir un efecte sinergètic. Per tal d'estudiar l'estat integral de contaminació a Tarragona, es desenvolupà un Índex de Risc Integral en base al SOM. Així, es va elaborar un ranking dels diversos contaminants en funció de la seva persistència, bioacumulació i toxicitat. Posteriorment, es va dissenyar un mapa del risc de la zona mitjançant la representació espacial de l'Índex amb un Sistema d'Informació Geogràfica.
Tot i que el risc per metalls pesants i contaminants orgànics no és significatiu, fóra molt recomanable dur a terme mesures continuades del nivells d'aquests i altres contaminants en les àrees industrials i urbanes de Tarragona. Així mateix, caldria fer un esforç conjunt per tal de reduir els nivells ambientals d'As, Cr i V.
Thesis: Human health risk assessment of exposure to environmental pollutants in the chemical/petrochemical industrial area of Tarragona (Catalonia, Spain).
Author: Martí Nadal
Summary:
One of the most important chemical/petrochemical complexes in Southern Europe is located in Tarragona (Catalonia, Spain). In recent years, public concern over possible adverse health effects for the population living near the industrial complex has increased. In response, in 2002 we initiated a wide survey to determine the current levels of various pollutants in the area. Specifically, samples of soils and vegetation (wild chards) were collected in several locations of the chemical and petrochemical industrial complex of Tarragona, as well as in Tarragona downtown and some residential suburbs. Finally, a few samples were collected outside the direct influence of the chemical industries (controls). Concentrations of arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), manganese (Mn), lead (Pb), and vanadium (V) were determined in those samples. In turn, the levels of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), as well as polycyclic aromatic hydrocarbons (PAHs) were also determined in the same samples.
Soils collected near the chemical complex and in urban/residential areas showed the highest concentrations for all the chemicals analyzed. The difference with respect to the petrochemical and unpolluted areas was significant for Cr, V, PCDD/Fs and PCBs. However, the levels of all pollutants in soil were clearly lower than the maximum allowed concentrations established by the legislation. With regard to chard samples, no significant differences were observed for any of the pollutants, excepting V. Consequently, it can be considered that Tarragona is impacted by some degree of pollution by this metal.
The application of Kohonen's Self-Organizing Map (SOM) and Principal Component Analysis (PCA) allowed to identify some sampling locations in the south-western corner of the chemical area, and in Tarragona downtown, due to relatively high levels of pollution. In fact, the presence of a chlor-alkali plant, as well as the predominant wind regime (from North) and the height of stacks and torches of the oil refinery (making easier the dispersion far away these sources), would be a reasonable explanation why higher concentrations were found in the chemical area.
The current concentrations of heavy metals do not pose relevant non-carcinogenic risks for the population. However, a certain number of cancer cases could derive from As ingestion (due to the low As levels established by US EPA) and Cr inhalation (according to the assumption that Cr+6 is 1/6 of the total chromium). Human health risk assessment of PCDD/F exposure was carried out according to the socioeconomic status of the population. The environmental exposure only means less than 2% of the total exposure. Overall, people of residential areas result more exposed to PCDD/Fs. However, non-carcinogenic and carcinogenic risks associated to that exposure would be assumable.
Considering the low levels of PAHs, the influence of the temperature and solar radiation on the PAH photodegradation was studied. It was found that both variables might have a synergistic effect over PAH degradation. To study the global state of pollution in the area of Tarragona, a SOM-based Integral Risk Index was developed. Inorganic and organic pollutants were ranked according to different properties of persistence, bioaccumulation, and toxicity. Subsequently, a risk map of the zone was designed as the spatial representation of this Index with a Geographic Information System (GIS).
Although the risk by heavy metals and organic pollutants is not notable, continuous measurements of these and other pollutants in the industrial and urban Tarragona are remarkably advisable. Likewise, some efforts should be done to reduce the environmental levels of As, Cr, and V.
47
Du, Preez Hein Hildegarde. "A methodology for undertaking freshwater fish chemical contaminant surveys for human health risk assessment / by Hein Hildegarde du Preez." Thesis, Potchefstroom University for Christian Higher Education, 2000. http://hdl.handle.net/10394/2160.
48
Picazo, Christine Pilar L. (Christine Pilar Lopez). "Human health risk assessment of Chemical Spill 4 at the Massachusetts Military Reservation dc by Christine Pilar L. Picazo." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41364.
49
Filho, José Prado Alves. "Receituário agronômico: a construção de um instrumento de apoio à Ggstão dos agrotóxicos e sua controvérsia." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/90/90131/tde-31082008-183047/.
Анотація:
O uso indiscriminado de agrotóxicos na agricultura brasileira e suas conseqüências sobre os aspectos ambientais e de saúde pública deram início a uma ampla campanha conduzida por agrônomos, extensionistas, ambientalistas e produtores rurais, visando a criação de mecanismos de controle do uso desses insumos químicos. Um dos caminhos construídos no Brasil para a gestão dos agrotóxicos foi o estabelecimento, através de legislação específica, da prescrição técnica obrigatória, a partir da participação de um profissional habilitado (engenheiro agrônomo ou florestal), como requisito para a comercialização dos agrotóxicos. O presente estudo visa discutir a situação atual de aplicação e uso do receituário agronômico, comparando os princípios que fundamentaram no passado a construção desse instrumento de gestão, com o quadro atual de utilização dessa prática. A parte inicial deste estudo apresenta um panorama geral sobre o uso de agrotóxicos. Em seguida, buscou-se investigar e discutir os fatores de origem da adoção do receituário agronômico, a partir do desenho de um quadro histórico do processo de proposição e adoção desse instituto. O passo seguinte foi dedicado a investigar as influências do processo de institucionalização do receituário agronômico e as distorções ocorridas em relação aos preceitos iniciais da proposta. Buscou-se também registrar subsídios sobre o atual contexto de aplicação e aplicabilidade do receituário agronômico.The unrestricted use of pesticides in Brazilian agriculture and its impact in environmental and public health aspects, motivated a broad range of initiatives conducted by agronomists, professionals of rural extension services, environmentalists and farmers, with the objective of creating new mechanisms of pesticides control. One of the ways built in Brazil for the management of pesticides was the establishment, through a specific legislation, of the mandatory technical prescription, written by a qualified professional (agronomist or forest engineer), as a requirement to pesticides commercialization. The aim of this study is to discuss the status of agronomic prescription use, comparing the principles that supported the construction of this management tool in the past with the adoption of this practice nowadays. The initial part of this study presents a general panorama on the use of pesticides in the agriculture. Soon afterwards, it was looked for to investigate and to discuss the factors of origin of the adoption of the agronomics prescriptions, starting from the drawing of a historical picture of the proposition process and adoption of that institute. The following step was dedicated to the investigation on the influences of the process of adoption of the technical prescription and the distortions happened in relation to the initial precepts of the proposal. It was also looked for to register subsidies on the current application context and applicability of the agronomics prescriptions.
50
Dobbins, Laura L. Brooks Bryan William. "Chemical toxicity distributions in aquatic toxicology relative sensitivities of estrogenicity assays and ecotoxicity of parabens in model freshwater organisms /." Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5350.