Academic literature on the topic 'Trace metal pollution'

Due to the specific geographical and hydrological structure of Boka Kotorska Bay, that is characterized by a low flow of water through the bay, the anthropogenic impact is pronounced, exerting direct effects on this unique ecosystem. Trace metal (Pb, Hg, Ni, Co and Cd) concentrations were measured in the winter, spring and fall of 2008 in two marine organisms (Posidonia oceanica and Mytilus galloprovincialis) selected as biomonitors of trace metals in the Boka Kotorska Bay. These marine organisms have the ability to accumulate trace metals from their environment. Metal pollution indexes (MPI) for both species were compared, confirming that the most polluted was Tivat bay and the least Kotor bay.

There is a growing public concern over the potential accumulation of heavy metals in soil, owing to rapid industrial development. In an effort to describe the status of the pollutions of soil by industrial activities, relevant data sets reported by many studies were surveyed and reviewed. The results of our analysis indicate that soils were polluted most significantly by metals such as lead, zinc, copper, and cadmium. If the dominant species are evaluated by the highest mean concentration observed for different industry types, the results were grouped into Pb, Zn, Ni, Cu, Fe, and As in smelting and metal production industries, Mn and Cd in the textile industry, and Cr in the leather industry. In most cases, metal levels in the studied areas were found to exceed the common regulation guideline levels enforced by many countries. The geoaccumulation index (Igeo), calculated to estimate the enrichment of metal concentrations in soil, showed that the level of metal pollution in most surveyed areas is significant, especially for Pb and Cd. It is thus important to keep systematic and continuous monitoring of heavy metals and their derivatives to manage and suppress such pollution.

Trace metals are a group of toxic pollutants that can cause serious damage to ecosystems and humans. To determine the distribution characteristics of aqueous trace metal contamination and identify critical pollution sources, it is necessary to develop a detailed estimation of trace metal emissions. By considering emission-related factors in each industrial sector, we estimate that the emissions were approximately 2, 61 t, 2,684 t, 301 t and 309 t for mercury, cadmium, chromium, arsenic and lead, respectively, in 2010 in China. These values are much higher than those provided in annual statistical reports. Our research identified critical emissions sources, including Shandong, Henan, Jiangsu and Guangdong Provinces and Raw Chemical, Non-ferrous Smelting, Non-ferrous Mining and Metal Products industries. However, Shandong and Metal Products are ignored in ‘The Twelfth 5-Year Plan for Complete Control of Trace Metal Pollution’. This research generally found that the allowable discharge levels had a significant impact on specific sectors. Total emissions are much lower than the maximum allowable under current Chinese emissions regulations but exceed limits recommended by Integrated Pollution Prevention and Control (European Union). Furthermore, our study found that many regions located along upstream reaches of the Yangtze River, like Sichuan Province, are sources of cross-boundary pollution.

This work appraises the extent of toxic trace metals and seasonal pollution degree in Damietta branch sediments of the River Nile of Egypt. The toxic trace metals Fe, Mn, Cd, Co, Cu, Ni, Pb, and Zn were analysed in sediments from six sites during the summer and winter seasons. The metal concentrations and organic matter were determined using inductively-coupled-plasma mass spectrometry and loss-on-ignition, respectively. Multivariate statistical methods were used in order to allocate the possible metals sources and their relationships in sediments. The seasonal mean sequence of toxic trace metals was: Fe > Mn > Zn > Pb > Cu > Ni > Co > Cd. The mean Cd, Pb, and Zn values exceeded the sediment quality guidelines and average shale and they represent severe potential toxicity for aquatic organisms. Cu and Co were enriched during winter. The geo-accumulation index stipulated that metal pollution degree in the sequence of: Pb > Zn > Cd > Co > Cu > Mn > Ni > Fe. The highest metal pollution index reported in winter in sites S4/S5 and during summer in sites S4–S6. Different agricultural, wastewater discharge, fisheries, and industrial activities, as well as the effect of dilution/concentration during summer/winter seasons, are the main factors that contributed to metal accumulations in Damietta branch sediments. Continuous monitoring and evaluation of toxic trace metal concentrations of the Damietta sediments and similar localities worldwide can help to protect the ecosystem from harmful metal contaminations.

Widely spread lichen specie Flavoparmelia caperata is used in a biomonitoring study for atmospheric trace metal pollution in natural ecosystems in Southeastern Serbia. The concentration and distribution pattern of 21 metals in lichens were determined by inductively coupled plasma atomic emission spectrometry. The difference observed between metal deposition in peripheral and central parts of lichen thalli reflected air quality changes in the last and previous years. These findings were confirmed with principal component analysis. Our study demonstrated the accumulation of Ba, K, Mg, Na, Tl and Zn in peripheral parts of thalli, while As, B, Cd, Cr, Cu, Fe, Ga, In, Li, Ni, Pb and Se were concentrated in central parts of thalli.

Trace heavy metals, such as arsenic, cadmium, lead, chromium, nickel, and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. In addition to these metals, copper, manganese, iron, and zinc are also important trace micronutrients. The presence of trace heavy metals in the atmosphere, soil, and water can cause serious problems to all organisms, and the ubiquitous bioavailability of these heavy metal can result in bioaccumulation in the food chain which especially can be highly dangerous to human health. This study reviews the heavy metal contamination in several areas of Pakistan over the past few years, particularly to assess the heavy metal contamination in water (ground water, surface water, and waste water), soil, sediments, particulate matter, and vegetables. The listed contaminations affect the drinking water quality, ecological environment, and food chain. Moreover, the toxicity induced by contaminated water, soil, and vegetables poses serious threat to human health.

Abstract Changes in the global environment such as ocean acidification (OA) may interact with anthropogenic pollutants including trace metals threatening the integrity of marine ecosystems. We analyze recent studies on the interactive effects of OA and trace metals on marine organisms with a focus on the physiological basis of these interactions. Our analysis shows that the responses to elevated CO2 and metals are strongly dependent on the species, developmental stage, metal biochemistry and the degree of environmental hypercapnia, and cannot be directly predicted from the CO2-induced changes in metal solubility and speciation. The key physiological functions affected by both the OA and trace metal exposures involve acid-base regulation, protein turnover and mitochondrial bioenergetics, reflecting the sensitivity of the underlying molecular and cellular pathways to CO2and metals. Physiological interactions between elevated CO2 and metals may impact the organisms’ capacity to maintain acid-base homeostasis and reduce the amount of energy available for fitness-related functions such as growth, development and reproduction thereby affecting survival and performance of estuarine populations. Environmental hypercapnia may also affect the marine food webs by altering predator-prey interactions and the trophic transfer of metals in the food chain. However, our understanding of the degree to which these effects can impact the function and integrity of marine ecosystems is limited due the scarcity of the published research and its bias towards certain taxonomic groups. Future research priorities should include studies of metal x PCO2 interactions focusing on critical physiological functions (including acid-base, protein and energy homeostasis) in a greater range of ecologically and economically important marine species, as well as including the field populations naturally exposed (and potentially adapted) to different levels of metals and CO2 in their environments.

The distribution of trace metals (Fe, Mn, Cu, Cd and Pb) has been determined in dissolved and particulate phases, along with relevant hydrographic parameters, from the nearshore coastal zone of the western North Sea (between 52ON and 56ON) during four Land Ocean Interaction Study (LOIS) surveys covering the seasonal cycle (autumn 1994 to summer 1995) The behaviour of the redox-sensitive metals, Fep and Mnp in the western North Sea were strongly correlated (r>0 44 for all seasons, P<0 05) in all surveys and exhibited maximum concentrations in winter (16 mg g -1 and 700 ug g-1 respectively) which progressively decreased throughout the year Distinct seasonal variations were also observed for particulate Cu, Cd and Pb For example, enhanced concentrations of Cup (36 ± 39 ug g-1) and Cdp (0.36 ± 0.42 ug g -1) in the Humber coastal zone during summer were attributed to preferential particulate organic/biogenic-metal interactions. In contrast enhanced, though diffuse, atmospheric inputs of Pb from continental winds were considered to have contributed to the elevated Pbp concentrations (82 ± 27 ug g -1) observed offshore during winter Results from radiotracer incubation experiments suggest that biological activity makes a significant contribution to the removal of dissolved Mn and Cd to the particulate phase. However, a phase lag of two to three months between maximum primary productivity and maximum particulate metal adsorption (KD=2 X 104 & 5 x 102 for Mn and Cd respectively) indicates a decoupling from the spring plankton bloom In general metal distributions in the Humber coastal zone were significantly influenced by freshwater discharge, tidal regime at the mouth of the estuary and prevailing wind conditions Total trace metal fluxes across the mouth of the Humber Estuary were highest during spring (311, 8 96 & 1045 kg day-1, for Cu, Cd and Pb respectively) and lowest during summer (25 7, 1 .12 & 33 4 kg day-1, for Cu, Cd and Pb respectively) They were dominated by variations in freshwater outflow and the tidal range during sampling On an annual basis comparison to estuarine inputs (rivers, industry and sewage sources) suggested retention of Cu (25%) and Cd (56%) Estimates of partitioning (KD) were derived from the dissolved and particulate data for Cu, Cd and Pb over the seasonal cycle Copper was dominated by the particulate phase (73-80%) in all seasons but summer, whilst Cd showed particulate phase dominance (54-70%) in autumn and winter only The Pb distributions were dominated by the particulate phase (94-99%) independent of season Trace metal settling velocities implied that the Humber Plume was acting as a sink for Cu, Cd and Pb in winter and spring However settling velocities calculated for Cd and Pb (flood tide) in summer were similar to background suspended particulate matter (SPM) suggesting long range transport with the residual circulation. Modelling of Pb isotopic ratios in the Humber Plume suggested that on average 32-39% of the extracted Pbp originated from anthropogenic sources The data from this study has given unique information concerning the concurrent seasonal distributions of particulate trace metals in the western North Sea and have yielded new insights into mechanisms affecting trace metal cycling and transport, essential in the development and refinement of coupled hydrodynamic-geochemical models.

Members of the meiobenthos have been used extensively to determine the effects of anthropogenic perturbation in marine systems (Coull & Chandler, 1992). Despite this, the meiofauna has been virtually excluded from freshwater pollution monitoring. This thesis aimed to address this research caveat, by evaluating the potential of stream meiofauna for monitoring metal-contamination. Meiofaunal communities were sampled from streams in SW England representing a gradient in metal contamination. Environmental variables in these streams were also measured to identify the important forcing agents structuring the stream benthos. Multivariate techniques demonstrated Cu, either alone or in combination with other environmental variables was of most importance in correlations with the composition of meiofaunal communities. Comparison with the macrofaunal data demonstrated that both components of the benthos responded in a similar way to metal contamination, although the meiofauna also highlighted other differences in water chemistry. The combination of meiofauna, macrofauna and temporary meiofauna in a combined metazoan community analysis gave the best discrimination of sites. Detection of metal-contamination was retained in meiofaunal data aggregated to the family level. The abundances of the harpacticoid copepod Bryocamptus zschokkei were consistently important in contributing to between-site differences in community structure. The harpacticoid, therefore was selected as an ecologically-relevant freshwater toxicity test for Cu. Laboratory experiments demonstrated that Cu had toxic effects on the survival and reproduction of Bryocamptus zschokkei. Although acute toxicity tests gave more rapid results, these effects on survival occurred at a higher Cu concentration than those in the chronic tests. Sub-lethal concentrations of Cu led to a reduction in the numbers of offspring per brood Animals with pre-exposure to chronic concentrations of Cu exhibited greater tolerance to this metal. In conclusion, more information may be gained by including the meiofauna, alongside the macrofauna, when monitoring the impact of contaminants on freshwater systems. To reduce the effort of processing samples it appears family level data could be used to detect metal-contamination. The novel use of B. zschokkei in laboratory tests, where it showed lethal and sub-lethal responses to Cu, demonstrated that this species may have much potential as an ecologically-relevant freshwater bioassay organism for this metal. The advantages of using meiofaunal species such as B. zschokkei as toxicity test organisms are discussed.

This thesis describes a novel application of an artificial neural network and links together the two diverse disciplines of electroanalytical chemistry and information sciences. The artificial neural network is used to process data obtained from a Differential Pulse Anodic Stripping (DPAS) electroanalytical scan and produces as an output, predictions of lead concentration in samples where the concentration is less than 100 parts per billion. A comparative study of several post analysis processing techniques is presented, both traditional and neural. Through this it is demonstrated that by using a neural network, both the accuracy and the precision of the concentration predictions are increased by a factor of approximately two, over those obtained using a traditional, peak height calibration curve method. Statistical justification for these findings is provided Furthermore it is shown that, by post processing with a neural network, good quantitative predictions of heavy metal concentration may be made from instrument responses so poor that, if using tradition methods of calibration, the analytical scan would have had to be repeated. As part of the research the author has designed and built a complete computer controlled analytical instrument which provides output both to a graphical display and to the neural network. This instrument, which is fully described in the text, is operated via a mouse driven user interface written by the author.

Urban soils are often contaminated with trace metals and the toxicity of the metals depends, in part, on their speciation in soil solutions. The objectives of this project were to estimate the metal speciation in urban soils and to evaluate the predictability of soil metal pools on plant uptake. The chemical speciation of Cd, Cu, Ni, Pb and Zn was estimated by using the Windermere Humic Aqueous Model (WHAM). In soil solutions, Cd, Ni and Zn were present mainly as free ions when the solutions were acidic and their organic complexes were dominant as the pH was over 7.5. The other two metals mostly formed complexes with organic ligands. The activities of Cd2+, Cu2+, Ni2+, Pb2+ and Zn 2+ were affected by soil pH and total soil metal burdens. All five metals were under-saturated with respect to the minerals which could potentially control the metal solubility.
Metal uptake by plants in the contaminated railway yards was generally not correlated with free, dissolved and total soil metal pools. A pot experiment demonstrated better correlations between the metal pools and the metal content in wild chicory. Multiple regression analysis showed that the metals in the leaves and roots of wild chicory could be adequately predicted by the soil total metals and soil properties such as pH and exchangeable Ca.

The concentrations of trace metals: cadmium, copper, nickel, lead and mercury, in addition to aluminium, iron and manganese were determined in the sediments and pore water (except aluminium) of the Forth estuary. Organic matter (as loss on ignition), total organic carbon (TOe), total organic nitrogen (TON), particle size and redox potential were also determined in the sediments. In addition, chloride, sulphate, conductivity, alkalinity, pH, dissolved organic carbon, phosphate and nitrate were determined in the sediments pore water. Trace metals in the pore water were determined using a modified preconcentration technique and measurements were carried out by graphite furnace. Mercury was measured using the p.s.a mercury specific fluorescence detector. organic matter (TOC & TON) in the sediments were measured using CHNS/O analyzer. Samples were collected at seasonal intervals for a period of 18 months on board the survey vessel "Forth Ranger". Six stations were selected to represent upper, middle and lower estuary. Sediment cores collected at each station were subjected to centrifugation under nitrogen gas atmosphere to separate the pore water after being sectioned at 2.5 cm intervals for a depth of 10 centimetres. Concentrations of trace metals in the Forth estuary varied from station to station and from one season to another. Mean concentrations for sediments were as follows (mg\kg): lead, 56.9; cadmium, 0.22; copper, 38.9; nickel, 33.7 and mercury, 1.86. For pore water, the mean concentraxxi tions (Jlg\l) were as follows: lead, 3.14; cadmium, 1.86; copper, 31.9; nickel, 24.7 and mercury, 0.075. Measurements of sulphates, nitrates, phosphate, conductivity and dissolved organic carbon were used to examine the processes controlling their distributions in the pore water. The results indicated that the distributions of nutrients (phosphate and nitrate) in the upper 10 cm seemed to be controlled by macro-infaunal irrigation activities and their values varied according to the overlying water conditions. The distributions of trace metals in the sediments were found to be controlled by particle size and organic matter both spatially and temporally. Vertical distribution of trace metals in the pore water were found to be controlled by redox potential variations especially for iron and manganese. Concentrations of trace metals (Pb, Hg, Ni, Cd and CU) in the pore water were found to be higher than that in the overlying water. Enrichment factors were limited to 10-50 fold increase. Lead and mercury were 10 fold higher while 50 fold higher were found for nickel, copper and cadmium. Benthic flux calculations showed a significant flux of trace metals both in the summer and winter. However, flux of copper, nickel and lead tended to increase in the summer. Spatially, the lower estuary showed a higher flux of trace metals than the upper and middle reaches of the estuary.

Three approaches were employed to examine the effects of elevated sediment trace metal concentrations on estuarine/marine macrobenthic invertebrate assemblages. The initial study examined macroinvertebrate communities along a known polymetallic gradient, Lake Macquarie, NSW (gradient study). The second study experimentally tested if sediments sourced from different locations within Lake Macquarie differentially influenced the recolonisation of benthic invertebrates. The third study investigated the different recolonisation patterns of benthic invertebrates into sediments spiked with increasing concentrations of sediment-bound cadmium. In the Lake Macquarie gradient study, four locations (Cockle Bay, Warner's Bay, Kooroora Bay and Nord's Wharf) were sampled in winter 2000 and summer 2003 using a hierarchical design (location > site > plot). On both sampling occasions, the sediments showed strong gradients in lead, cadmium and zinc concentrations emanating from the Cockle Bay industrialised region in the lake's north, with concentrations being significantly lower in the most southern and less urbanised location (Nord's Wharf). In general, concentrations of lead, cadmium and zinc in the sediments increased among locations in the following order: Nord's Wharf > Kooroora Bay > Warner's Bay > Cockle Bay. AVSJSEM analyses indicated that in some sites in Cockle Bay, and to a lesser extent Warner's Bay, SEM concentrations exceeded their molar equivalence of AVS, indicating the potential for trace metals to be labile within the porewaters. Granulometry also changed along the gradient, with a higher proportion of silt/clay occurring in the locations with high metal concentrations. Conversely, the percentage of total organic carbon was higher in the less contaminated locations. In winter 2000, changes in benthic communities along the gradient supported the a priori hypotheses, with diversity and richness being greater in locations with lower concentrations of metals. Polychaetes were most numerous in Cockle Bay and Warner's Bay, whilst bivalves and gastropods were more abundant in Nord's Wharf and Kooroora Bay. Crustaceans were more numerous in Nord's Wharf; with all other locations having similar, lower, abundances. Ordination maps of the assemblages provided relatively clear separation of the assemblages among locations, with nonparametric multivariate analysis of variance (NPMANOVA) and subsequent pair-wise comparisons finding significant differences among the assemblages from all locations. SIMPER analyses found the highest level of dissimilarity was between the Nord's Wharf and Cockle Bay assemblages - primarily attributable to differences in the relative contributions of isopods; tellenid bivalves; and the polychaete families Spionidae, Opheliidae and Nephytidae. Weighted Spearman rank correlations (BIOENV) identified cadmium (Pw =0.74) as the strongest environmental (single or combination) variable to correlate with biotic assemblages. Benthic patterns along the gradient were less defined in summer 2003 due to a dramatic reduction in the abundance and diversity of fauna in Nord's Wharf. This decline was possibly attributable to a sustained reduction in salinity caused by a prolonged rainfall event. With the exception of Nord's Wharf, trends in the community indices and abundances of key taxa among the other locations were similar to those reported in winter 2000. Multivariate analyses discriminated the benthic assemblages from the four locations, with the findings from the NPMANOVA pair-wise comparisons indicating that the assemblages from all four locations were significantly different. SIMPER analyses showed the highest level of dissimilarity was between Nord's Wharf and Warner's Bay, with these differences being primarily attributable to their relative abundances of amphipods and polychaetes from the families Spionidae, Cirratulidae, Opheliidae and Capitellidae. BIOENV found that the combination of the sedimentary concentrations of cadmium and iron provided the best correlation (Pw =0.73) with biotic patterns, with similar correlations occumng with the addition of lead and its covariate, zinc (Pw =0.72). The combined findings from the gradient study established a strong correlation between trace metal concentrations within the sediments and suite of univariate and multivariate measurements. The low abundance and diversity of fauna in Nord's Wharf in the summer of 2003 highlighted the dynamic changes which can occur in the distributions of macrobenthic invertebrates. Although the study indicated that there was a strong relationship between trace metal concentrations and benthic community structure, the study was correlative, and requires subsequent experimental testing to confirm the causality of the observed relationships. The second component of the research was a translocation experiment using benthic recolonisation as an end-point. The experiment was performed to identify if the sediments, and not location, were influencing the composition of benthic assemblages in Lake Macquarie. Sediments were collected from three locations (Cockle Bay, Warner's Bay and Nord's Wharf), defaunated, and transplanted in three new locations along the south-east edge of the lake. At each location, 10 containers of each treatment were randomly placed in the sediment and allowed to recolonise for 22 weeks. Upon retrieval, the benthic communities were sampled and enumerated in conjunction with a variety of chemical and sedimentary measurements. Ten replicate invertebrate samples were also collected in the sediments adjacent to the experiment (ambient samples) at the completion of the experiment. Due to human interference, the containers from only two locations were analysed. Upon retrieval, pH and redox profiles of the sediments were similar to those expected in natural sediments. In general, concentrations of metals were low in the porewaters; however, iron precipitation on the porewater collection devices may have artificially increased the diffusion of metals, increasing concentrations near the sediment-water interface. Concentrations of SEM exceeded their AVS equivalence in some samples taken from the Cockle Bay and Warner's Bay treatments. Two-way ANOVAs found significant interactions between location and sediment treatments in diversity, evenness and the number of polychaetes, as well as significant differences in the number of capitellids and crustaceans among locations. Post-hoc comparisons of means found the Nord's Wharf sediment contained a higher mean number of individuals than the other treatments, including the ambient samples. nMDS ordination plots for both locations provided poor graphical discrimination of the assemblages among treatments; however, NPMANOVA detected significant location and treatment interactions. In both locations, pair-wise comparisons indicated that the assemblages within the Nord's Wharf treatments were significantly different to the Cockle Bay, Warner's Bay and ambient assemblages. No significant differences were detected between the Cockle Bay and Warner's Bay assemblages at either location. SIMPER analyses found the highest level of dissimilarity occurred between the ambient assemblages in Location 2 and the Nord's Wharf treatment, primarily due to the relative difference in the abundances of Capitellidae, Spionidae, Oweniidae, Nereididae and isopods among the assemblages. The findings from the translocation experiment suggest that the sediments are influencing the recolonisation of benthos. However, because differences were not detected between the Cockle Bay and Warner's Bay treatments, the approach used in the study shows potential as an in situ technique which could be used to assess the potential ecological risks of sediments fiom specific locations. Excluding cost and time considerations, the technique's primary disadvantage is the lack of a true control. As a result, the technique can only identify if the sediments are modifying benthic recolonisation, and not causality. The final component of the research experimentally tested if elevated concentrations of sediment-bound cadmium affected benthic invertebrate recolonisation. Sediments from the south coast of New South Wales (Durras Lake) were defaunated, and spiked with cadmium under anaerobic conditions to obtain three targeted cadmium concentrations: control (