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Journal articles on the topic "Cadmium – Environmental aspects"
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Benavides, María P., Susana M. Gallego, and María L. Tomaro. "Cadmium toxicity in plants." Brazilian Journal of Plant Physiology 17, no. 1 (March 2005): 21–34. http://dx.doi.org/10.1590/s1677-04202005000100003.
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Heavy metals are important environmental pollutants and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional, and environmental reasons. Plants posses homeostatic cellular mechanisms to regulate the concentration of metal ions inside the cell to minimize the potential damage that could result from the exposure to nonessential metal ions. This paper summarizes present knowledge in the field of higher plant responses to cadmium, an important environmental pollutant. Knowledge concerning metal toxicity, including mechanisms of cadmium homeostasis, uptake, transport and accumulation are evaluated. The role of the cell wall, the plasma membrane and the mycorrhizas, as the main barriers against cadmium entrance to the cell, as well as some aspects related to phytochelatin-based sequestration and compartmentalization processes are also reviewed. Cadmium-induced oxidative stress was also considered as one of the most studied topics of cadmium toxicity.
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Pokhilyuk, Natalia V., and Anatoly L. Gorbachev. "Ethnic aspects of toxic elements in the Russian Northeast." RUDN Journal of Ecology and Life Safety 30, no. 1 (May 31, 2022): 58–66. http://dx.doi.org/10.22363/2313-2310-2022-30-1-58-66.
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One of the urgent problems of ecology is the environmental pollution of the northern regions with toxic elements and their negative impact on human health. The analysis of the content of lead, cadmium and mercury in the body of aboriginal and visiting residents of the Northeast of Russia was carried out. The balance of essential (calcium, zinc) and toxic (lead, cadmium) elements was considered. Statistically significant differences in the content of cadmium and lead in aboriginal residents and Caucasians were noted. Among the Evens, the median of cadmium exceeded that of the Koryaks, Chukchis, and Caucasoids; the value of the median of lead among the Chukchis was lower compared to that in other ethnic groups. There were no statistically significant differences in the content of mercury between Koryaks, Evens and Chukchis, as well as between aboriginal residents and Caucasians. There are no critical levels of mercury in the body of aborigines. The median mercury in the hair of the Koryaks, Chukchis and Evens did not exceed the biologically acceptable level - 0.5 µg/g. Among aboriginal residents, the highest percentage of samples with mercury content in the range from 0.5 to 1.0 µg/g (background level) was noted in 33.8% of Evens and 30% of Koryaks; among the Chukchi, this figure was 8.6%. Elevated levels of mercury in some aboriginal people may be due to the high proportion of fish and seafood containing methylmercury in the diet. The proportions of toxic metals (Pb, Cd) in relation to their essential antagonist elements (Ca, Zn) indicate that toxic elements do not disrupt the biochemical processes controlled by the corresponding essential elements. Thus, the study area of the Northeast of Russia, in terms of toxic load on the population, can be attributed to territories with a relatively favorable environmental situation.
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Kress, Nurit. "Chemical Aspects of Coal Fly Ash Disposal at Sea: Predicting and Monitoring Environmental Impact." Water Science and Technology 27, no. 7-8 (April 1, 1993): 449–55. http://dx.doi.org/10.2166/wst.1993.0581.
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Monitoring studies at a deep sea fly ash dumping site found that the ash accumulates at the sea bed, causing a physical change in the sediments. Partial leaching of cadmium and chromium to seawater was detected in laboratory experiments, but no evidence of it was found in the sediments or benthic fauna sampled at the dumping site.
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Lodeiro, Pablo, Roberto Herrero, and Manuel E. Sastre de Vicente. "Thermodynamic and Kinetic Aspects on the Biosorption of Cadmium by Low Cost Materials: A Review." Environmental Chemistry 3, no. 6 (2006): 400. http://dx.doi.org/10.1071/en06043.
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Environmental Context. The toxicity of cadmium in waters can be decreased by using a wide variety of low-cost biomaterials. A number of such investigations are reviewed here and the models used to describe the process of biosorption discussed. Fundamental investigations that probe the thermodynamics and kinetics of the biosorption process are essential for a strong understanding of all biosorption processes. Areas that still need addressing are highlighted, in particular with regard to cadmium biosorption, some models for which are ready to be tested in pilot plants. Abstract. Cadmium is internationally recognized as an important pollutant in the environment, and different methods for its removal from wastewaters (chemical precipitation being the most commonly used) have been reported in the literature. Those methods are in most cases oriented to situations with high concentrations of the pollutant. Thus, alternative removal and recovery methods are being considered for removing very low concentrations of cadmium. These methods are all based on biosorption, the passive adsorption and sequestration of metals by several natural materials of biological origin. In this review we have considered the biosorption of cadmium onto biomaterials from a physicochemical, thermodynamic, and kinetic perspective. The thermodynamic perspective is based on the characterization of the interactions of the binding sites of the biosorbents with cadmium species in aqueous solution. Traditionally, this approach has been quantified using different kinds of isotherms. In addition, the description is completed by taking into account electrostatic effects, and the influence of pH and ionic strength, which are associated with the negative charge developed, in most cases, by the biomaterial. The other point of view in this review is the kinetic one, which is necessary for a full physicochemical description of the sorbate–biosorbent system. Consequently, an updated description of the various approaches commonly employed in kinetic studies in biosorption has been carried out.
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Draghici, George A., Cristina A. Dehelean, Iulia Pinzaru, Despina M. Bordean, Georgeta Pop, and Dragos V. Nica. "An 112 Days Experiment on Dietary Cadmium Retention in Hepatopancreas in Adult Cantareus aspersus Snails." Revista de Chimie 70, no. 8 (September 15, 2019): 2803–4. http://dx.doi.org/10.37358/rc.19.8.7431.
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Cadmium is very hazardous pollutant with massive impact on aspects of everyday life. Little knowledge exists on kinetics of dietary cadmium retention in Cantareus aspersus for durations above three months although this species of land snails serves as excellent ecotoxicological model for studying cadmium hazard. Here was used a continuous 112-day exposure study design, in which test snails were exposed to a wide range of dietary cadmium levels, including human- and environmentally-relevant levels. Using Flame Atomic Absorption Spectrometry, cadmium levels in the hepatopancreas were found to increase significantly, and in dose-dependent manner starting from a dietary cadmium dose of 0.2 mg/kg dry weight. The results of the present study render the hepatopancreas of mature snails, C. aspersus, as excellent endpoints for assessing Cd toxicity over a broad range of concentrations. Hence, this species of land snails can be reliably used for both active and passive biomonitoring of environmental cadmium pollution.
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Hazelhoff Roelfzema, W., A. M. Roelofsen, and J. H. J. Copius Peereboom-Stegeman. "Light microscopic aspects of the rat placenta after chronic cadmium administration." Science of The Total Environment 42, no. 1-2 (March 1985): 181–84. http://dx.doi.org/10.1016/0048-9697(85)90017-8.
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Nuss, Philip. "Losses and environmental aspects of a byproduct metal: tellurium." Environmental Chemistry 16, no. 4 (2019): 243. http://dx.doi.org/10.1071/en18282.
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Environmental contextStudies involving modelling are increasingly being performed to better understand how technology-critical elements such as tellurium are transported and accumulated in man-made technological systems. The resulting ‘anthropogenic cycles’ provide estimates of current and anticipated future material releases to the environment, and their associated environmental implications. This information complements data on natural cycles in which the subsequent transport and fate of tellurium in the environment can be examined. AbstractGlobal demand for tellurium has greatly increased owing to its use in solar photovoltaics. Elevated levels of tellurium in the environment are now observed. Quantifying the losses from human usage into the environment requires a life-cycle wide examination of the anthropogenic tellurium cycle (in analogy to natural element cycles). Reviewing the current literature shows that tellurium losses to the environment might occur predominantly as mine tailings, in gas and dust and slag during processing, manufacturing losses, and in-use dissipation (situation in around 2010). Large amounts of cadmium telluride will become available by 2040 as photovoltaic modules currently in-use reach their end-of-life. This requires proper end-of-life management approaches to avoid dissipation to the environment. Because tellurium occurs together with other toxic metals, e.g. in the anode slime collected during copper production, examining the life-cycle wide environmental implication of tellurium production requires consideration of the various substances present in the feedstock as well as the energy and material requirements during production. Understanding the flows and stock dynamics of tellurium in the anthroposphere can inform environmental chemistry about current and future tellurium releases to the environment, and help to manage the element more wisely.
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K. Samrane and A. Bouhaouss. "CADMIUM IN PHOSPHOROUS FERTILIZERS: BALANCE AND TRENDS." RASAYAN Journal of Chemistry 15, no. 03 (2022): 2103–17. http://dx.doi.org/10.31788/rjc.2022.1536865.
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The fertilizer industry is developing its activities by processing and upgrading natural phosphates, for several years that it has been in a conformist dynamic to face environmental, economic, financial, and political constraints. These constraints have incubated a significant industrial evolution in terms of technological progress, product diversification, knowledge, and innovation. Specifically, in wet phosphoric acid manufacturing, the 1980s brought a huge upheaval and changes in terms of strategies and practices following the development of environmental regulations. The environmentalist awareness, linked to the political and community trends, has resulted in the development of regulatory norms, as well as strict market demand for high-quality phosphoric acid and fertilizers products. Thus, cadmium has become an increasing concern to the phosphate industry and is considered one of the most important challenges currently facing the fertilizer industry for continuous market supply and growth. The present article gives an overview of cadmium in terms of market, applications, exposure, mobility, and bioavailability, and discusses balance and figures regarding cadmium in the phosphate and fertilizer industry. The article also outlines the technological aspects of cadmium removal from wet phosphoric acid, considering recent developments and conclusions that still confirm a challenge to find out an economic and available technology. Keywords: Cadmium, Phosphoric Acid, Market, Balance, Phosphate Fertilizers.
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Kärrman, E., and H. Jönsson. "Normalising impacts in an environmental systems analysis of wastewater systems." Water Science and Technology 43, no. 5 (March 1, 2001): 293–300. http://dx.doi.org/10.2166/wst.2001.0309.
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In an environmental systems analysis of four wastewater systems, the environmental aspects were prioritised by normalisation of predicted impacts from the studied systems to the total impacts from society. Priority Group 1 (highest priority) consisted of discharges (flows) of nitrogen, cadmium, lead and mercury to water, recycling of nitrogen and phosphorus to arable land and flows of heavy metals to arable land. A conventional wastewater system (A) was compared to irrigation of energy forest with biologically treated wastewater (B), liquid composting of toilet wastewater (C) and a conventional system supplemented with urine separation (D). Analysing the aspects in priority group one, systems B–D improved the management of plant nutrients and decreased the flow of heavy metals to water, while the flow to arable land increased, especially for system B. The suggested method is useful in municipal environmental planning and when choosing a wastewater system.
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Dong, J., W. H. Mao, G. P. Zhang, F. B. Wu, and Y. Cai. "Root excretion and plant tolerance to cadmium toxicity - a review." Plant, Soil and Environment 53, No. 5 (January 7, 2008): 193–200. http://dx.doi.org/10.17221/2205-pse.
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Significant quantities of Cd have been added to soils globally due to various anthropogenic activities, posing a serious threat to safe food production and human health. Rhizosphere, as an important interface of soil and plant, plays a significant role in the agro-environmental system. This article presents a review of relationship between root excretion and microorganisms and plant resistance to Cd toxicity and possible mechanisms. Root exudates markedly altered in species and quantity under Cd stress. Root exudates can affect Cd absorption by plants through changing the physical and chemical characteristics of rhizospheres. The influence of root exudates on Cd bioavailability and toxicity may include modifying the rhizosphere pH and Eh, chelating/complexing and depositing with Cd ions, and altering the community construction, the numbers and activities of rhizospheric microbes. In this paper, the methods to reduce the transfer of Cd in soil-plant system by adjusting rhizosphere environment are discussed, and some aspects are also proposed that should be emphasized in the future research work.
Dissertations / Theses on the topic "Cadmium – Environmental aspects"
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Jacob, Jeffery R. "Comparison of amendments for field-scale phytotreatment of lead, cadmium, and zinc." Virtual Press, 2006. http://liblink.bsu.edu/uhtbin/catkey/1355602.
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Phytoextraction is an innovative method that can be implemented to remove lead (Pb), cadmium (Cd), and zinc (Zn) from contaminated soil. A two-year field and growth chamber study was conducted to determine the effectiveness of several soil amendments in the phytoextraction or stabilization of Pb, Cd and Zn. Field plots were established at the Memorial Drive Dump site (Muncie, IN). Amendments included composted municipal solid waste (MSW) (25 Mg/ha), dried sewage sludge (SS) (25 Mg/ha), citric acid (2 mmol/kg soil), ethylenediaminetetraacetic acid (EDTA) (2 mmol/kg soil), and a control. A mixed grass crop was capable of survival and growth in the contaminated soil; in contrast, Helianthus annuus (sunflower) and Ambrosia artemisiifolia (ragweed) failed to become established. Soil Pb and Zn occurred primarily in the carbonate, organic-bound and residual forms (23.1%, 31.8%, and 44.4%, Pb, respectively and 11.4%, 26.5%, and 60.2% Zn, respectively). Soil Cd occurred primarily in the soluble, carbonate, and residual forms (21.8%, 21.3%, and 27.4%, respectively). In a growth chamber leaching study, soil Pb was most rapidly leached from the 0.1 M EDTA treatment (51.7 mg Pb over 200 pore volumes); the 0.001M resulted in the lowest leaching. Soil Pb was most rapidly leached using 0.1 M HEDTA (52.1 mg Pb over 200 pore volumes). The 0.001 M HEDTA rate resulted in lowest Pb leaching. Addition of an NPK solution resulted in minimal Pb leached. The MSW and dried sludge treatments resulted in the greatest dry matter production on the plots. Dry matter production was significantly (p >0.05) higher in the MSW (1.09 MT/ha) and SS (95 MT/ha) treatments. Addition of EDTA, citric acid and MSW significantly (p < 0.05) increased the amount of Cd uptake into plant tissue. The study also demonstrated the ability of vegetation to establish and grow on toxic soil and to uptake Pb, Cd, and Zn.Department of Natural Resources and Environmental Management
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Hamidian, Amir Hossein, and n/a. "Cadmium in the marine environment." University of Otago. Department of Chemistry, 2008. http://adt.otago.ac.nz./public/adt-NZDU20090728.100026.
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Cadmium in the ocean has a nutrient-like cycling pattern: with biological uptake at the surface, subsequent sinking in particulate form and then regeneration as dissolved species in deeper waters. Many measurements have been made over time of the ratio of the concentrations of dissolved Cd to those of PO₄ (Cd/PO₄) in the world ocean and this has become one of the best relationships documented between a trace metal and a nutrient. Combined with the measurements of the Cd/Ca ratio in foraminifera, the Cd/PO₄ ratio has been used to reconstruct the oceanographic circulation patterns that existed during past glacial periods and hence provides information on past climate changes.
In the present study Cd/PO₄ ratios of the Southern Indian Ocean in surface and deep waters were investigated. The slopes of the relationships between Cd and PO₄ concentrations in waters of this region are high compared to the global correlations, and lie between those reported for other parts of the Southern Ocean and the Pacific Ocean. In surface waters of the Southern Indian Ocean, Cd/PO₄ ratios decrease from regions exhibiting high nutrient-low chlorophyll (HNLC) characteristic in the south to oligotrophic waters further north. It is also found that particulate Cd plays an important role in regulating the high Cd/PO₄ ratios reported in waters south of the Polar Front.
Very low Cd/PO₄ ratios were measured in waters associated with the Subtropical Front southeast of New Zealand compared to other Southern Ocean and global oceanic waters. Seasonal variations in the Cd/PO₄ ratios measured for these waters strongly suggest they are associated with a significant biological uptake of dissolved Cd particularly during the phytoplankton growth season in summer.
Dissolved Fe concentrations in the Southern Indian Ocean and seasonal variations of Fe in waters off the Otago Coast (southeast of New Zealand) suggest that Fe may stimulate phytoplankton growth and this might result in lower Cd/PO₄ ratios in surface waters through enhanced Cd uptake relative to PO₄ by the phytoplankton. However there is no distinct relationship between dissolved Fe concentrations and the dissolved Cd/PO₄ ratios measured in these surface waters. This finding is in disagreement with the recent 2006 hypothesis put forward by J.T. Cullen, which proposed that waters exhibiting low dissolved Cd/PO₄ ratios were associated with the HNLC regions. From a consideration of the potential Zn concentrations calculated from Si concentration measurements reported for these waters, it would appear that Zn may play a more important role than Fe in regulating Cd/PO₄ ratios in these waters.
Measurements of dissolved and total Cd concentrations relative to those of PO₄ were also undertaken in the Otago Harbour and immediate surrounding coastal waters. These exhibited higher Cd concentrations and higher Cd/PO₄ ratios than open ocean waters further off the Otago Coast. The particulate Cd concentrations showed a negative correlation with Cd concentrations measured in cockle species (Austrovenus stuchburyi) collected in the harbour, suggesting that particulate Cd is not the source of Cd measured in the tissue of this species.
The concentrations of Cd and other trace metals were also measured in samples of green mussel (Perna canaliculus), ribbed mussel (Aulacomya atra maoriana) and oyster (Saccostrea cucullata) collected from Otago Harbour and possible correlations explored between these concentrations and other parameters such as the shellfish condition indices and environmental gradients in the harbour.
In summary, measurements of dissolved and particulate Cd concentrations in the water column can provide unique information on a number of processes occurring in the global marine environment.
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Kuroiwa, Kirk D. "The identification of indigenous vegetation capable of survival in lead-contaminated environments." Virtual Press, 2001. http://liblink.bsu.edu/uhtbin/catkey/1221308.
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Evaluation of heavy metal accumulation in soils and plants is of environmental importance due to their health effects on humans and other biota. Phytoremediation is an emerging technology that can stabilize or remove heavy metals in soil utilizing metal tolerant plant species (metallophytes). The objectives of this study were to: (1) assess a Superfund site, and a lead-acid battery dump for concentrations of soil lead (Pb) and cadmium (Cd); (2) assess the various chemical fractions of Pb and Cd at both sites; (3) identify native herbaceous vegetation surviving in the contaminated soils; and (4) evaluate plant uptake of Pb and Cd. Soil Pb and Cd concentrations at the Superfund site averaged 55,480 and 8.5 mg/kg, respectively. Soil Pb at the Superfund site occurred primarily in the carbonate, sulfide/residual, and organic chemical fractions (41.6, 28.6, and 26.7, respectively). Soil Pb and Cd concentrations at the dump site averaged 29,400 and 3.9 mg/kg, respectively. Soil Pb occurred mostly in the organic and carbonate fractions as 48.5 and 42.5% respectively. Plant uptake of Pb at both sites ranged from non-detectable (Agrostemma githago, Plantago rugeli, Alliaria officinalis shoots), to 1800 mg/kg (Agrostemma githago root). Cd uptake was maximal in Taraxacum officinale at 15.4 mg/kg (Superfund site). In the majority of plants studied, root Pb and Cd content was higher than for shoots (>_65%). Tissue and soil fractions yielded r2 of 0.61 and 0.57 for the soluble and carbonate-Pb fractions, respectively. The plants with the greatest tissue concentrations of Pb and Cd were predominantly herbaceous species, some of which produce sufficient biomass to be practical for phytoremediation technologies.Department of Natural Resources and Environmental Management
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Turner, Philip K. "Effects on Survival, Reproduction and Growth of Ceriodaphnia dubia following Single Episodic Exposure to Copper or Cadmium." Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc4831/.
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Effects of episodic exposures have gained attention as the regulatory focus of the Clean Water Act has shifted away from continuous-flow effluents. Standardized laboratory toxicity tests require that exposure be held constant. However, this approach may not accurately predict organism responses in the field following episodic exposures such as those associated with rain-driven runoff events or accidental pollutant discharge. Using a modified version of the 7-day short-term chronic test recommended by the US Environmental Protection Agency, Ceriodaphnia dubia were exposed to copper or cadmium for durations ranging from 1 minute to 24 hours. In addition, adult reproductive recovery and effects on second generation individuals was assessed following select copper exposures. Finally, cadmium exposures were compared in reconstituted hard water (RHW) and municipal treated wastewater effluent (TWE). Following exposure, organisms were transferred to clean RHW or TWE and maintained for the remainder of the test. No- and lowest observed effect concentrations (NO- and LOECs) increased logarithmically with respect to logarithmic decreases in duration regardless of metal, endpoint or water type. Effective concentrations of cadmium however, were usually higher than those of copper, especially in TWE. LOECs for C. dubia survival following 24-hour and 5-minute exposures to copper were 116 and 417 µg/L, respectively. LOECs for fecundity were 58 and 374 µg/L, respectively. Neonate production of first generation adult C. dubia appeared to recover from pulsed copper exposure upon examination of individual broods. Cumulative mean neonate production however, showed almost no signs of recovery at exposure durations ≥3 hours. Pulse exposure to copper also resulted in diminished fecundity of unexposed second generation individuals. Such effects were pronounced following parental exposure for 24 hours but lacking after parental exposures ≤3 hours. LOECs for C. dubia survival following 24-hour and 5-minute exposures to cadmium in RHW were 44 and 9000 µg/L, respectively. LOECs for fecundity were 16 and 5000 µg/L, respectively. In TWE, LOECs for C. dubia survival were 83 and >10,000 µg/L, respectively. LOECs for fecundity in TWE were 48 and 7000 µg/L, respectively. Runoff pollution is site and event specific, however, data presented herein may be useful as a predictive tool under various conditions.
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White, Jessica C. "Comparative Bioavailability of Dietary and Dissolved Cadmium to Freshwater Aquatic Snails." Thesis, University of North Texas, 2003. https://digital.library.unt.edu/ark:/67531/metadc4351/.
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Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During the 15-day exposure, samples were taken to determine Cd concentration in snail soft tissue, snail shell, algal food, and overlying water. Analyses of snail soft tissue and shells indicate that exposure route significantly affects Cd concentrations in the tissues. In both cases, dissolved Cd is the primary contributor to metal body burden.
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Gu, Yingying, and 顾莹莹. "Electrokinetic remediation of cadmium-contaminated natural clay of high buffer capacity." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46279015.
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McGee, Chandra J. "Concentrations of Cadmium in Common Moose Browse in Maine." Fogler Library, University of Maine, 2006. http://www.library.umaine.edu/theses/pdf/McGeeCJ2006.pdf.
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He, Yue, and 贺悦. "Characterization of metal stabilization effect by X-ray diffraction technique and nano-indentation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47753067.
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The technological development and application of waste-to-resource strategy is
significantly critical and crucial in both environmental and manufacturing industries, via
which we do not only provide practical treatments to toxic waste materials but also
translate them into usable products. It has been considered as a preferred method which
should be applied in future wastewater treatment strategies.
In this study, we investigated the process of incorporating cadmium oxide and nickel
oxide into ceramic-based materials with the phases of CdAl4O7, and CdFe2O4. Such
products are of less harmful effect to the natural environment and can also be of
beneficial use with their good mechanical properties identified by nano-indentation. We
proved the possibility and provided an opportunity to convert the waste from
wastewater treatment process to a new material resource.
XRD is preferred for characterizing solid mixtures to determine the relative
abundances of crystalline phases during the reaction process. As a result, we can obtain
the relative abundance information on the growth of the crystalline products, such as
CdAl4O7, and CdFe2O4 according to the change of fabrication temperatures. In that case,
the starting reaction temperature and the optimized temperature (at which the completed
reaction could be achieved) could be revealed. In Cd-Al system, the starting temperature
for CdAl4O7 formation is 900 °C, and the optimized formation temperature is around
1020 °C. On the other hand, for Cd-Fe system, such temperatures are of 700 °C and
850 °C correspondingly.
In our research, it is shown that the ceramic-process is an effective strategy to
stabilize the waste hazardous metals (cadmium and nickel) by materials such as
aluminate, ferrite, and kaolin commonly used in ceramic industry. Through this method,
the difficult-to-treat wasted metals would become reusable and applied in building and
infrastructure projects. Products containing CdAl4O7, CdFe2O4 and NiAl2O4 have
shown higher resistance to acidic leaching, comparing to CdO and NiO used as the
starting materials to simulate the waste metal forms discharged from the industrial
stream. Furthermore, similar measurements by alkaline attack on the sintered products
(NiAl2O4 containing samples) were also studied.
Besides the investigation to leaching behavior, the mechanical properties are also
measured by nano-indentation in our work. The incorporation of metal waste into the
fabrication of ceramic products is valuable due to the preferred stabilization
mechanisms of crystal structures and the large volume of ceramic products needed by
the construction industry. Furthermore, because the product safety and functionality
should not be compromised, a fundamental understanding of the surface properties of
metal containing phases should be further established, rather than relying solely on data
from regulatory tests on bulk samples. Therefore, the results of this study demonstrate
the superior mechanical properties of nickel spinel containing products, comparing to
the cristobalite silica matrix, under severe acid attack.published_or_final_version
Civil Engineering
Master
Master of Philosophy
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Kaoser, Saleh. "Concept of copper mobility and compatibility with lead and cadmium in landfill liners." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84268.
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Despite improved liner design, there are still reported incidences of landfill leachate, rich in heavy metals, percolating through to groundwater and threatening ecosystems. This thesis introduces the concept of segregating municipal solid wastes (MSW) according to their major heavy metals and their metal's adsorption compatibility. Each segregated portion can be disposed in a different landfill compartment to minimize leaching of these heavy metals with the greatest bioactive impact. The validity of the concept was evaluated by batch and column retention mobility studies using copper (Cu) alone or with either lead (Pb) or cadmium (Cd) in solutions bearing various pHs. This was supported by selective sequential extraction (SSE) to determine the affinity to specific liner fractions. The following summarizes the procedure used.Beforehand, a soil column test using sand with 5 and 10% bentonite was conducted to develop an equation predicting liner permeability, k , under simulated field conditions. The column permeability test revealed that a liner with 5% bentonite resulted in a k value which respected the North American criteria of 10-5 m/s.
In the batch experiments, solutions with Cu alone or with Cd or Pb, adjusted to pH of 3.7, 5.5 or 7.5, were applied to sand liners with 0%, 5% or 10% bentonite, having CEC's of 2.0, 6.4, and 10.8 (cmol(+) kg-1 ), respectively. Bentonite, pH and Pb significantly affected Cu adsorption. Cu was adsorbed by the liners at pH <6.5 whereas Cu precipitated at pH >6.5. Cu retention was higher in the presence of Cd than in that of Pb, at all combinations of CEC and pH. Competition between metals was greater in liners with lower CEC and therefore fewer adsorption sites. Limiting Pb in a landfill compartment can improve Cu adsorption at pH's below the precipitating threshold.
In the SSE procedure, the liner samples were centrifuged, decanted from their solutions and each adsorption fraction analyzed for Cu content. Results indicated that the carbonate fraction adsorbed more Cu, and that Pb significantly increased the mobility of Cu due to competition for exchangeable sites.
In the final soil column test using a sand liner with 5% bentonite, the leachate had an initial pH of 3.7. The leaching test confirmed the compatibility of Cu with Cd. The leaching of Cu was greater in the presence of Pb. Total metals in leachate was greater for the Cu-Cd solutions than for the Cu-Pb, because of Cd's relatively high mobility. The sequential extraction results showed again that the carbonate fraction dominated metal adsorption. Total heavy metal leaching followed the order of Cu/Cd > Cu/Pb > Cu alone.
Thus, disposing MSW in landfill compartments based on their heavy metal compatibility can minimize migration of heavy metals.
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Carrier, Roxie. "Temperature Tolerance of Freshwater Fish Exposed to Water-Borne Cadmium." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc504077/.
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Lethal toxicity values (96 h LC50; mg Cd/L) for the test species were similar: Lepomis cyanellus, 11.52; Notropis lutrensis, 6.62; Pimephales promelus, 3.58. However the effects of cadmium concentration and exposure time on temperature tolerance varied between species. Neither cadmium concentration nor exposure time had a significant effect on the CTM of green sunfish. Both cadmium concentration and exposure time had a significant effect on the CTMs of red shiners and fathead minnows. By day 10 mean CTMs were 2.3 t- 4.5 C (red shiners) and 4.2 to 5.7 C (fathead minnows) lower than control CTM. These results suggest a potential problem in cadmium contaminated systems for high environmental temperatures to stress or kill fish.
Books on the topic "Cadmium – Environmental aspects"
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Parvau, Reini G. Cadmium in the environment. Hauppauge, N.Y: Nova Science Publishers, 2009.
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Parvau, Reini G. Cadmium in the environment. Hauppauge, N.Y: Nova Science Publishers, 2009.
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1927-, Stoeppler M., and Piscator Magnus 1932-, eds. Cadmium: [proceedings]. Berlin: Springer-Verlag, 1988.
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Eberhard, Böhm. Massnahmen zur Minderung des Cadmiumeintrags in die Umwelt. Karlsruhe: Fraunhofer-Institut für Systemtechnik und Innovationsforschung, 1990.
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Ewers, Ulrich. Untersuchungen zur Cadmiumbelastung der Bevölkerung in der Bundesrepublik Deutschland. Berlin: E. Schmidt, 1990.
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Support, United States Occupational Safety and Health Administration Directorate of Technical. Protective measures for controlling exposure to cadmium: Appendix A. Washington, D.C: U.S. Dept. of Labor, Occupational Safety and Health Administration, 1987.
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Christensen, Thomas H. Cadmium soil sorption at low concentrations. [Lyngby, Denmark]: Polyteknisk forlag, 1989.
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Louekari, Kimmo. Kadmium ympäristössä. Helsinki: Vesi- ja ympäristöhallitus, 1991.
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O, Nriagu Jerome, and Sprague John B, eds. Cadmium in the aquatic environment. New York: Wiley, 1987.
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10
Cossa, Daniel. Le cadmium en milieu marin biogéochimie et ecotoxicologie. Brest: IFREMER, 1989.
Find full textBook chapters on the topic "Cadmium – Environmental aspects"
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Agrawal, Bipin Jagdishprasad. "Prospective Sustainability of Utilization of Effective Techniques for Remediation of Heavy Metals From Textile Effluents." In Research Anthology on Emerging Techniques in Environmental Remediation, 517–42. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-3714-8.ch028.
Full textAbstract:
Textile industries are one of the prevalent water consumers and contaminators ensuing high generation of waste water. Wastewater from dyeing and printing units is often rich in organic compounds, colours, and heavy metals containing residues of various dyes and chemicals. Among these waste water pollutants, heavy metals are of serious environmental concern in recent years. Metals are extensively used for manufacture of synthetic dyestuffs and for colouration of natural dyes on textiles to achieve different shades and hues. Heavy metals such as lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), zinc (Zn), copper (Cu), etc. are widely used for production of colour pigments of textile dyes. These heavy metals, highly toxic, get conveyed to the environment, and can bio-accumulate in the human body, aquatic life, natural water-bodies, and also possibly become trapped in the soil. The chapter deals with the utilization of heavy metals in textile wet processing, their important characteristics, various toxic aspects, and different methods for their elimination from the textile effluent liquors.
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Agrawal, Bipin Jagdishprasad. "Prospective Sustainability of Utilization of Effective Techniques for Remediation of Heavy Metals From Textile Effluents." In Biostimulation Remediation Technologies for Groundwater Contaminants, 19–49. IGI Global, 2018. http://dx.doi.org/10.4018/978-1-5225-4162-2.ch002.
Full textAbstract:
Textile industries are one of the prevalent water consumers and contaminators ensuing high generation of waste water. Wastewater from dyeing and printing units is often rich in organic compounds, colours, and heavy metals containing residues of various dyes and chemicals. Among these waste water pollutants, heavy metals are of serious environmental concern in recent years. Metals are extensively used for manufacture of synthetic dyestuffs and for colouration of natural dyes on textiles to achieve different shades and hues. Heavy metals such as lead (Pb), chromium (Cr), cadmium (Cd), iron (Fe), zinc (Zn), copper (Cu), etc. are widely used for production of colour pigments of textile dyes. These heavy metals, highly toxic, get conveyed to the environment, and can bio-accumulate in the human body, aquatic life, natural water-bodies, and also possibly become trapped in the soil. The chapter deals with the utilization of heavy metals in textile wet processing, their important characteristics, various toxic aspects, and different methods for their elimination from the textile effluent liquors.
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Yılmaz, Bayram. "Endokrin Bozucuların Güncel Durumu, Ağır Metaller, Poliklorlu Bifeniller (PCBS), Parabenler, BHA, BHT." In Endokrin Bozucular ve Sağlık, 11–34. Türkiye Bilimler Akademisi Yayınları, 2022. http://dx.doi.org/10.53478/tuba.978-625-8352-04-7.ch02.
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Endocrine Disrupting Chemicals (EDCs) are a global problem for environmental and human health. They are defined as “an exogenous chemical, or mixture of chemicals, that can interfere with any aspect of hormone action”. It is estimated that there are about 1000 chemicals with endocrine-acting properties. EDCs comprise pesticides, fungicides, industrial chemicals, plasticizers, nonylphenols, metals, pharmaceutical agents and phytoestrogens. Persistent Organochlorine Pollutants (POPs) are substances that persist a long time in the environment and pose a threat for human health. Polychlorinated Biphenyls (PCBs) are a group of POPs that were widely used and banned in 1980s. PCBs may have neurotoxic, carcinogenic, immunotoxic, hepatatoxic, nephrotoxic and cytotoxic effects. Some PCBs resemble to estradiol 17-β and hence can mimic estrogenic effects. In contrast, coplanar PCBs mimic dioxin that they bind to aryl hydrocarbon receptor and causes anti-estrogenic effects. Heavy metals (mercury, lead, arsenic, cadmium and uranium) have been reported to have endocrine disruptive effects. However, their carcinogenic, neurotoxic and other adverse effects on human health are more important. Parabens are methyl, ethyl, propyl and ester forms of PHBA that are commonly used in food, pharmaceutical and personal care products. They have weak endocrine disruptive effects. Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are food additives as antioxidants. There are very few studies on the endocrine disruptor effects of BHA and BHT. Their use has been limited in USA, EU and Canada. Human exposure to EDCs mainly occurs by ingestion and to some extent by inhalation and dermal uptake. Most EDCs are lipophilic and bioaccumulate in the adipose tissue, thus they have a very long half-life in the body. It is difficult to assess the full impact of human exposure to EDCs because adverse effects develop latently and manifest at later ages, and in some people do not present. Timing of exposure is of importance. Developing fetus and neonates are the most vulnerable to endocrine disruption. EDCs may interfere with synthesis, action and metabolism of sex steroid hormones that in turn cause developmental and fertility problems, infertility and hormone-sensitive cancers in women and men. Some EDCs exert obesogenic effects that result in disturbance in energy homeostasis. Interference with hypothalamo-pituitary-thyroid and adrenal axes has also been reported. Potential EDCs, their effects and mechanisms of action, epidemiological studies to analyze their effects on human health, bio-detection and chemical identification methods, studying EDCs in humans and recommendations for endocrinologists, individuals and policy makers are reviewed.
Conference papers on the topic "Cadmium – Environmental aspects"
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Case, G. G., and R. L. Zelmer. "Comparative Experiences in Environmental Remediation of LLR Waste Sites in Diverse Canadian Environments." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4846.
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A variety of sites contaminated with legacy low-level radioactive (LLR) waste materials have been identified across Canada. Many of these sites, associated with former radium and uranium refining and processing operations, are located in urbanized areas of southern Ontario. However, other sites have been discovered at more remote locations in Canada, including northern Alberta and the Northwest Territories. The diversity of waste froms, ranging from pitchblende ore and processing wastes, to discarded luminescent products, combined with construction and transportation logistical issues encountered at these sites, present ongoing challenges for the Low-Level Radioactive Waste Management Office (LLRWMO) to overcome in meeting its mandate to resolve these legacy problems. Since its establishment in 1982, the federal government’s LLRWMO has operated programs to characterize and delineate contaminated historic waste sites across Canada. These programs have included undertaking property decontaminations, waste consolidation and interim storage projects at many sites, and participating with federal and provincial government departments and local communities to consider long-term storage and disposal opportunities. This paper compares four specific environmental remediation programs conducted by the LLRWMO within diverse Canadian settings found at Port Hope and Toronto (southern Ontario), Fort McMurray (northern Alberta), and Vancouver (west coast of British Columbia). Contaminant characterization and delineation, and remediation plan design and implementation aspects of these individual programs span the time period from the early 1980s through to 2002. The individual programs dealt with a variety of legacy waste forms that contained natural radioactive materials such as radium-226, total uranium, total thorium and thorium-230, as well as coincidental inorganic contaminants including arsenic, barium, cadmium, cobalt, lead, mercury, vanadium and zinc. Application of the lessons learned during these individual programs, as well as the development of new and innovative technologies to meet the specific needs of these programs, have enabled the LLRWMO to effectively and efficiently implement environmental remediation solutions that address the variety of Canada’s legacy LLR wastes.introduction.
Reports on the topic "Cadmium – Environmental aspects"
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Avis, William. Technical Aspects of e-Waste Management. Institute of Development Studies, March 2022. http://dx.doi.org/10.19088/k4d.2022.051.
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Population growth, increasing prosperity and changing consumer habits globally are increasing demand for consumer electronics. Further to this, rapid changes in technology, falling prices, increased affordability and consumer appetite for new products have exacerbated e-waste management challenges and seen millions of tons of electronic devices become obsolete. This rapid literature review collates evidence from academic, policy focussed and grey literature on the technical aspects e-waste value chains. The report should be read in conjunction with two earlier reports on e-waste management1. E-waste is any electrical or electronic equipment, including all components, subassemblies and consumables, which are part of the equipment at the time the equipment becomes waste. The exact treatment of Waste from Electrical and Electronic Equipment (WEEE) can vary enormously according to the category of WEEE and technology that is used. Electrical and electronic items contain a wide variety of materials. As a result of this complex mix of product types and materials, some of which are hazardous (including arsenic, cadmium, lead and mercury and certain flame retardants) multiple approaches to WEEE are required, each with specific technical guidelines. This report is structured as follows: Section two provides an introduction to the technical aspects of e-waste management, including a reflection on the challenges and complexities of managing a range of product types involving a range of components and pollutants. Section three provides an annotated bibliography of key readings that discuss elements of the technical aspects of managing e-waste. This bibliography includes readings on national guidelines, training manuals and technical notes produced by the Basel convention and courses. WEEE recycling can be a complex and multifaced process. In order to manage e-waste effectively, the following must be in place Legislative and regulatory frameworks Waste Prevention and minimisation guidelines Identification of waste mechanisms Sampling, analysis and monitoring expertise Handling, collection, packaging, labelling, transportation and storage guidelines Environmentally sound disposal guidelines Management is further complicated by the speed of technological advance with technologies becoming redundant much sooner than initially planned. Case studies show that the average actual lifetimes of certain electronic products are at least 2.3 years shorter than either their designed or desired lifetimes.