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Metal Pollution (metal + pollution)
Kinds of Metal Pollution Selected AbstractsStream Macroinvertebrate Community Affected by Point-Source Metal PollutionINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 3 2007Hideyuki Doi Abstract The impacts of mining activities on aquatic biota have been documented in many stream ecosystems. In mining streams, point-source heavy metal pollution often appears in the stream. We hypothesize that this pollution is toxic to macroinvertebrates owing to high concentrations of metals and therefore affects macroinvertebrate community structure. We investigated macroinvertebrate community structure in mountain streams, including heavy metal-polluted sites and neutral-pH streams, to determine the relationship between community structure and environmental factors such as low pH and heavy metal concentrations. Based on multidimensional scaling ordination, the macroinvertebrate community at heavy metal pollution sites was remarkably different from that at the other sites. Inductively coupled plasma mass spectrometry revealed high concentrations of aluminum and iron in surface water at the polluted sites. Macroinvertebrate community structure at the metal pollution sites was significantly different from that at other sites in the same stream and in neutral-pH streams. Thus, point-source metal pollution may reduce the density and diversity of in situ macroinvertebrates. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Acid Mine Drainage and Heavy Metal Pollution from Solid Waste in the Tongling Mines, ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2008XU Xiaochun Abstract: Based on investigation of the characteristics of solid waste of two different mines, the Fenghuangshan copper mine and the Xinqiao pyrite mine in Tongling, Anhui province in central-east China, the possibility and the differences of acid mine drainage (AMD) of the tailings and the waste rocks are discussed, and the modes of occurrence of heavy metal elements in the mine solid waste are also studied. The Fenghuangshan copper mine hardly produces AMD, whereas the Xinqiao pyrite mine does and there are also differences in the modes of occurrence of heavy metal elements in the tailings. For the former, toxic heavy metals such as Cu, Pb, Zn, Cd, As and Hg exist mostly in the slag mode, as compared to the latter, where the deoxidization mode has a much higher content, indicating that large amounts minerals in the waste rocks have begun to oxidize at the earth surface. AMD is proved to promote the migration and spread of the heavy metals in mining waste rocks and lead to environmental pollution of the surroundings of the mine area. [source] Response of macroinvertebrates to copper and zinc in a stream mesocosmENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2002Christopher W Hickey Abstract Metal pollution of streams and rivers is recognized as one of the major concerns for management of freshwaters. Macroinvertebrate communities were established within 12 artificial streams and exposed to three replicated concentrations of a metals mixture (copper and zinc) for 34 d. The cumulative criterion units (CCU = ,[metals]/hardness-adjusted U.S. Environmental Protection Agency [U.S. EPA] 1996 chronic criterion value) of total metals in the low, medium, and high treatments were 2.4, 5.9, and 18 CCUs. Zinc comprised approximately 75% of the CCUs in each of the treatments. Effects on taxa richness and the number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) were moderate at the high exposure concentration (,23% and ,26% respectively, p < 0.05). All of the five major mayfly species showed near extinction, whereas four of the seven caddisflies showed stimulation (up to +121%) and three were reduced (up to ,76%). Redundancy analysis for this metal gradient indicated that 94% of the variance in community structure was explained by three quantitative variables: total mayfly abundance, a mollusk (Potamopyrgus antipodarum) abundance, and the number of EPT individuals, indicating that multiple indices do provide improved predictors of metal stress. Most species showed a threshold response relationship, whereas some community indicators showed apparent hormetic responses (e.g., number of mayfly taxa, total taxa, and number of EPT taxa). Model concentration-response relationships with generalized linear models were used to provide threshold of 20% effective concentration values for species and community metrics. Threshold effect values ranged upwards of 1.4 CCUs, indicating that U.S.EPA chronic criteria would be protective of species and community responses. [source] Effects of environmental pollution on microsatellite DNA diversity in wood mouse (Apodemus sylvaticus) populationsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2005Veerle Berckmoes Abstract Ten microsatellite DNA loci were surveyed to investigate the effects of heavy metal pollution on the genetic diversity and population genetic structure of seven wood mouse (Apodemus sylvaticus) populations along a heavy metal pollution gradient away from a nonferrous smelter in the south of Antwerp (Flanders, Belgium). Analysis of soil heavy metal concentrations showed that soil Ag, As, Cd, Cu, and Pb decreased with increasing distance from the smelter. Genetic analyses revealed high levels of genetic variation in all populations, but populations from the most polluted sites in the gradient did not differ from those of less-polluted sites in terms of mean observed and expected heterozygosity level and mean allelic richness. No correlation was found between measures of genetic diversity and the degree of heavy metal pollution. However, an analysis of molecular variance and a neighbor-joining tree suggested a contamination-related pattern of genetic structuring between the most polluted and less polluted sites. Pairwise FST values indicated that populations were significantly genetically differentiated, and assignment tests and direct estimates of recent migration rates suggested restricted gene flow among populations. Additionally, genetic differentiation increased significantly with geographical distance, which is consistent with an isolation-by-distance model. We conclude that, at least for our microsatellite DNA markers, genetic diversity in the studied wood mouse populations is not affected greatly by the heavy metal pollution. [source] Assessing trace-metal exposure to American dippers in mountain streams of southwestern British Columbia, CanadaENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2005Christy A. Morrissey Abstract To develop a suitable biomonitor of metal pollution in watersheds, we examined trends in exposure to nine trace elements in the diet (benthic invertebrates and fish), feathers (n = 104), and feces (n = 14) of an aquatic passerine, the American dipper (Cinclus mexicanus), from the Chilliwack watershed in British Columbia, Canada. We hypothesized that key differences may exist in exposure to metals for resident dippers that occupy the main river year-round and altitudinal migrants that breed on higher elevation tributaries because of differences in prey metal levels between locations or possible differences in diet composition. Metals most commonly detected in dipper feather samples in decreasing order were Zn > Cu > Hg > Se > Pb > Mn > Cd > Al > As. Resident dipper feathers contained significantly higher mean concentrations of mercury (0.64 ,g/g dry wt), cadmium (0.19 ,g/g dry wt), and copper (10.8 ,g/g dry wt) relative to migrants. Mass balance models used to predict daily metal exposure for dippers with different diets and breeding locations within a watershed showed that variation in metal levels primarily was attributed to differences in the proportion offish and invertebrates in the diet of residents and migrants. In comparing predicted metal exposure values to tolerable daily intakes (TDI), we found that most metals were below or within the range of TDI, except selenium, aluminum, and zinc. Other metals, such as cadmium, copper, and arsenic, were only of concern for dippers mainly feeding on insects; mercury was only of concern for dippers consuming high fish diets. The models were useful tools to demonstrate how shifts in diet and breeding location within a single watershed can result in changes in exposure that may be of toxicological significance. [source] Posidonia oceanica as a biomonitor of trace elements in the gulf of naples: Temporal trends by lepidochronology,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2004Stefania Ancora Abstract Levels of Hg, Cd, Pb, Cu, Zn, Fe, and Mn were assessed by using Posidonia oceanica as a bioindicator in the Gulf of Naples (southern Italy). Lepidochronology, which enables retroactive dating of scales and rhizomes of this seagrass, was combined with atomic spectrometry to assess temporal trends of trace elements in dated scales and rhizomes over a 10-year period. Lepidochronology occasionally has been used to monitor Hg in dated scales, but never has been used to determine concentrations of other trace elements in dated rhizomes. Data were compared between various structural parts of seagrass and between sampling sites. Concentrations of some elements found in dated scales or rhizomes showed a similar trend in most of the sites; increasing for Hg and Cu and decreasing for Pb, Fe, and Zn. Contaminant levels indicated by seagrass meadows varied from metal to metal. Concentrations of Hg, Cd, and Pb fell within the ranges measured in other areas considered to have low levels of heavy metal pollution, whereas Cu, Mn, and Zn had higher concentrations only in some years. However, on the basis of other studies, none of the sampling sites are considered to have high contamination levels. [source] Field contamination of the starfish Asterias rubens by metals.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2003Part 1: Short-, long-term accumulation along a pollution gradient Abstract The accumulation of Cd, Pb, Zn, and Cu in the starfish Asterias rubens was studied in a Norwegian fjord characterized by a gradient of metal pollution in the sediments, ranging from very high metal concentrations at its head to much lower levels at its opening. The concentrations of metals in starfish from natural populations along the gradient (long-term accumulation) and in starfish that were transferred up the gradient (short-term accumulation) were compared. At long-term, Cd and Pb accumulations by starfish living at normal salinity (30,) were related to the level of contamination of of the environment while Cu and, to a lesser extent, Zn accumulations appeared strictly controlled. At short-term, Pb was accumulated steadily, Cd and Zn were accumulated transiently in the pyloric caeca (fast compartment), and Cu was not accumulated at all. Depuration experiments (transfer down the gradient) showed that Cd and Pb were efficiently eliminated from the pyloric caeca but not from the body wall (slow compartment). It is concluded that Pb is chronically accumulated, without apparent control, Cd is subjected to a regulating mechanism in the pyloric caeca which is overwhelmed over the long-term; Zn is tightly controlled in the pyloric caeca and Cu in both pyloric caeca and body wall. A distinct color variety of starfish is restricted to the low salinity (22-26,) superficial water layer. This variety showed a different pattern of metal accumulation over the long-term. This pattern is attributed to the particular hydrological conditions prevailing in this upper layer. [source] Development of photosynthetic biofilms affected by dissolved and sorbed copper in a eutrophic riverENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2002Christiane Barranguet Abstract Photosynthetic biofilms are capable of immobilizing important concentrations of metals, therefore reducing bioavailability to organisms. But also metal pollution is believed to produce changes in the microalgal species composition of biofilms. We investigated the changes undergone by natural photosynthetic biofilms from the River Meuse, The Netherlands, under chronic copper (Cu) exposure. The suspended particles in the river water had only a minor effect on reduction of sorption and toxicity of Cu to algae. Biofilms accumulated Cu proportionally to the added concentration, also at the highest concentration used (9 ,M Cu). The physiognomy of the biofilms was affected through the growth of the chain-forming diatom Melosira varians, changing from long filaments to short tufts, although species composition was not affected by the Cu exposure. The Cu decreased phosphate uptake and algal biomass measured as chl a, which degraded exponentially in time. Photosynthetic activity was always less sensitive than algal biomass; the photon yield decreased linearly in time. The protective and insulating role of the biofilm, supported by ongoing autotrophic activity, was indicated as essential in resisting metal toxicity. We discuss the hypothesis that the toxic effects of Cu progress almost independently of the species composition, counteracting ongoing growth, and conclude that autotrophic biofilms act as vertical heterogeneous units. Effective feedback mechanisms and density dependence explain several discrepancies observed earlier. [source] Induction of morphological deformities in Chironomus tentans exposed to zinc- and lead-spiked sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2001Edward A. Martinez Abstract Laboratory experiments were used to assess morphological responses of Chironomus tentans larvae exposed to three levels of zinc and lead. Chironomus tentans egg masses were placed into triplicate control and metal-spiked aquaria containing the measured concentrations 1,442, 3,383, and 5,562 ,g/g Pb dry weight and 1,723, 3,743, and 5,252 ,g/g Zn dry weight. Larvae were collected at 10-d intervals after egg masses were placed in aquaria until final emergence. Larvae were screened formouthpart deformities and metal body burdens. Deformities increased with time of exposure in both Zn and Pb tanks. Deformity rates between the three Zn concentrations differed statistically, with low and medium Zn levels containing the highest overall deformity rates of 12%. Deformity rates for larvae held in the Pb aquaria were found to differ significantly. Larvae in the low-Pb tanks had a deformity rate of 9%. Larvae and water from both the Zn and Pb aquaria had increasing metal concentrations with increasing sediment metal concentration. Results demonstrate that Zn and Pb each induce chironomid mouthpart deformities at various concentrations. However, a clear dose-related response was not demonstrated. Our research provides more support for the potential use of chironomid deformities as a tool for the assessment of heavy metal pollution in aquatic systems. [source] Cadmium accumulation by invertebrates living at the sediment,water interfaceENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 4 2001Landis Hare Abstract Benthic animals can take up trace metals both from the sediment compartment in which they burrow and from the water column compartment above their burrows (we define both compartments as containing water and particles). If criteria for the protection of benthic animals are based on metal concentrations in one of these two compartments, then it should first be demonstrated that the majority of the metal taken up by these animals comes from the given compartment. To determine whether benthic animals take up the majority of their cadmium (Cd) from the sediment compartment, we created a Cd gradient in lake sediment and compared Cd accumulation by the invertebrates colonizing these sediments with Cd concentrations in the sediment compartment. On the basis of this relationship and using a bioaccumulation model, we estimate that indigenous benthic invertebrates take up the majority of their Cd from the water column compartment. The results of our experiment are similar to those from a previous study conducted on a different benthic community in a larger lake. Taxa common to both lakes obtained similar proportions of their Cd from the water column compartment, suggesting that Cd accumulation by the same species will be constant across lakes of differing size and chemistry. Our results strengthen the argument that the protection of benthic communities from metal pollution should consider metal in both the water column and sediment compartments. In this regard, the AVS model, which considers only sedimentary metals, was more effective in predicting Cd concentrations in pore waters than those in most animal taxa. We suggest that measurements of vertical chemical heterogeneity in sediments and of animal behavior would aid in predicting the bioaccumulation and effects of sedimentary pollutants. [source] Fate of airborne metal pollution in soils as related to agricultural management.EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2007Summary The fate of airborne metal pollutants in soils is still relatively unknown. We studied the incorporation of such airborne metal pollution in two soils under long-term permanent pasture (PP) and conventional arable land (CA). Both soils were located at an almost equal distance from a former zinc smelter complex and developed under comparable pedogenetic conditions. Profiles of total concentrations of Zn, chosen as a mobile, and Pb as a little- or non-mobile element, were examined and compared with macro- and micromorphological soil characteristics (soil colour, biological activity). The two soils showed different profiles of total Zn and Pb concentrations, with a marked decrease of concentrations of both elements under the plough layer in CA, whereas the decrease was more progressive in PP. However, the stocks of Zn and Pb for the 1-m soil profiles of CA and PP were comparable. Correlation of Zn and Pb concentration at different depths with total Fe contents and comparison with estimated data for the local geochemical background (LGCB), suggests transport of Zn from the surface to depth in CA and PP, and Pb movement in PP. In CA, 53% of Zn and 92.5% of Pb stocks derived from airborne metal pollution were located at depths < 26 cm. In PP, only 40% of Zn and 82% of Pb, derived from airborne pollution, were found in the A11 and A12 horizons (< 26 cm), the remaining 18% of the Pb stock being incorporated until 50 cm depth; one-third of total Zn stock ascribed to airborne pollution was found at depths > 50 cm. Studies of the composition of gravitational water collected in soils from the same study area suggest two mechanisms for metal movement. First, mobile metal ions (Zn2+) move in the soil solution and are intercepted by iron-clay complexes in deeper soil horizons. Second, observed only in PP, simultaneous movement of Zn and Pb is ascribed to bioturbation by earthworms. [source] Humus forms and metal pollution in soilEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2002S. Gillet Summary Smelters in northern France are a serious source of soil pollution by heavy metals. We have studied a poplar plantation downwind of an active zinc smelter. Three humus profiles were sampled at increasing distance from the smelter, and the thickness of topsoil horizons was measured along a transect. We analysed the vertical distribution of humus components and plant debris to assess the impact of heavy metal pollution on the humus forms and on soil faunal activity. We compared horizons within a profile, humus profiles between them, and traced the recent history of the site. Near the smelter, poplar trees are stunted or dead and the humus form is a mor, with a well-developed holorganic OM horizon. Here faunal activity is inhibited, so there is little faecal deposition and humification of plant litter. At the distant site poplar grows well and faunal activity is intense, so there are skeletonized leaves and many organo,mineral earthworm and millipede faecal pellets. The humus form is a mull, with a well-developed hemorganic A horizon. The passage from mor to mull along the transect was abrupt, mor turning to mull at 250 m from the smelter, though there was a progressive decrease in heavy metal deposition. This indicates that there was a threshold (estimated to be 20 000 mg Zn kg,1) in the resilience of the soil foodweb. [source] Exploiting the genetic and biochemical capacities of bacteria for the remediation of heavy metal pollutionFEMS MICROBIOLOGY REVIEWS, Issue 4 2002Marc Valls Abstract The threat of heavy metal pollution to public health and wildlife has led to an increased interest in developing systems that can remove or neutralise its toxic effects in soil, sediments and wastewater. Unlike organic contaminants, which can be degraded to harmless chemical species, heavy metals cannot be destroyed. Remediating the pollution they cause can therefore only be envisioned as their immobilisation in a non-bioavailable form, or their re-speciation into less toxic forms. While these approaches do not solve the problem altogether, they do help to protect afflicted sites from noxious effects and isolate the contaminants as a contained and sometimes recyclable residue. This review outlines the most important bacterial phenotypes and properties that are (or could be) instrumental in heavy metal bioremediation, along with what is known of their genetic and biochemical background. A variety of instances are discussed in which valuable properties already present in certain strains can be combined or improved through state-of-the-art genetic engineering. In other cases, knowledge of metal-related reactions catalysed by some bacteria allows optimisation of the desired process by altering the physicochemical conditions of the contaminated area. The combination of genetic engineering of the bacterial catalysts with judicious eco-engineering of the polluted sites will be of paramount importance in future bioremediation strategies. [source] Reconstructing floodplain sedimentation rates from heavy metal profiles by inverse modellingHYDROLOGICAL PROCESSES, Issue 1 2002Dr Hans Middelkoop Abstract The embanked floodplains of the lower River Rhine in the Netherlands contain large amounts of heavy metals, which is a result of many years deposition of contaminated overbank sediments. Depending on local sedimentation rates and changing pollution trends in the past, the metal pollution varies greatly between different floodplain sections as well as vertically within the floodplain soil profiles. Maximum metal concentrations in floodplain soils vary from 30 to 130 mg/kg for Cu, from 70 to 490 mg/kg for Pb and from 170 to 1450 mg/kg for Zn. In the present study these metals were used as a tracer to reconstruct sedimentation rates at 28 sites on the lower River Rhine floodplains. The temporal trend in pollution of the lower River Rhine over the past 150 years was reconstructed on the basis of metal concentrations in sediments from small ponds within the floodplain area. Using a one-dimensional sedimentation model, average sedimentation rates over the past century were determined using an inverse modelling calibration procedure. The advantage of this method is that it uses information over an entire profile, it requires only a limited number of samples, it accounts for post-depositional redistribution of the metals, and it provides quantitative estimates of the precision of the sedimentation rates obtained. Estimated sedimentation rates vary between about 0·2 mm/year and 15 mm/year. The lowest metal concentrations are found in the distal parts of floodplain sections with low flooding frequencies and where average sedimentation rates have been less than about 5 mm/year. The largest metal accumulations occur in low-lying floodplain sections where average sedimentation rates have been more than 10 mm/year. Copyright © 2002 John Wiley & Sons, Ltd. [source] Indoor/outdoor concentrations and elemental composition of PM10/PM2.5 in urban/industrial areas of Kocaeli City, TurkeyINDOOR AIR, Issue 2 2010B. Pekey Abstract, This study presents indoor/outdoor PM2.5 and PM10 concentrations measured during winter and summer in 15 homes in Kocaeli, which is one of the most industrialized areas in Turkey. Indoor and outdoor PM2.5 and PM10 mass concentrations and elemental composition were determined using an X-ray fluorescence spectrometer. Quantitative information was obtained on mass concentrations and other characteristics such as seasonal variation, indoor/outdoor (I/O) ratio, PM2.5/PM10 ratio, correlations and sources. Average indoor and outdoor PM2.5 concentrations were 29.8 and 23.5 ,g/m3 for the summer period, and 24.4 and 21.8 ,g/m3 for the winter period, respectively. Average indoor and outdoor PM10 concentrations were 45.5 and 59.9 ,g/m3 for the summer period, and 56.9 and 102.3 ,g/m3 for the winter period, respectively. A varimax rotated factor analysis (FA) was performed separately on indoor and outdoor datasets in an effort to identify possible heavy metal sources of PM2.5 and PM10 particle fractions. FA of outdoor data produced source categories comprising polluted soil, industry, motor vehicles, and fossil fuel combustion for both PM fractions, while source categories determined for indoor data for both PM2.5 and PM10 comprised industry, polluted soil, motor vehicles, and smoking, with an additional source category of cooking activities detected for the PM2.5 fraction. Practical Implications In buildings close to industrial areas or traffic arteries, outdoor sources may have an important effect on indoor air pollution. Therefore, indoor and outdoor investigations should be conducted simultaneously to assess the relationship between indoor and outdoor pollution. This study presents the simultaneous measurement of PM fractions (PM2.5 and PM10) and their elemental compositions to determine the sources of respirable PM and the heavy metals bound to these particles in indoor air. Factor analysis of indoor data indicated that the contribution of outdoor pollutant sources to indoor pollution was about 70%, making these sources the most significant for indoor heavy metal pollution, wheras other sources of indoor pollution included smoking and cooking activities. [source] Stream Macroinvertebrate Community Affected by Point-Source Metal PollutionINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 3 2007Hideyuki Doi Abstract The impacts of mining activities on aquatic biota have been documented in many stream ecosystems. In mining streams, point-source heavy metal pollution often appears in the stream. We hypothesize that this pollution is toxic to macroinvertebrates owing to high concentrations of metals and therefore affects macroinvertebrate community structure. We investigated macroinvertebrate community structure in mountain streams, including heavy metal-polluted sites and neutral-pH streams, to determine the relationship between community structure and environmental factors such as low pH and heavy metal concentrations. Based on multidimensional scaling ordination, the macroinvertebrate community at heavy metal pollution sites was remarkably different from that at the other sites. Inductively coupled plasma mass spectrometry revealed high concentrations of aluminum and iron in surface water at the polluted sites. Macroinvertebrate community structure at the metal pollution sites was significantly different from that at other sites in the same stream and in neutral-pH streams. Thus, point-source metal pollution may reduce the density and diversity of in situ macroinvertebrates. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Heavy metal pollution in Antarctica: a molecular ecotoxicological approach to exposure assessmentJOURNAL OF FISH BIOLOGY, Issue 2000C. W. Evans Trematomus bernacchii sampled from two sites at Ross Island, Antarctica, were assessed for condition (gonadal and hepatic somatic indices and condition factor), pathological state (liver and gill histology), hepatic metal (Zn, Cu, Cd and Ni) concentrations, and metallothionein induction by quantitative competitive (qc) RT-PCR. Fish from a polluted site (Winter Quarters Bay) had pathological anomalies including necrosis and periductal inflammation in their livers, and X-cell disease, epithelial hyperplasia, lamellar fusion and aneurysms in their gills. Such anomalies were less common in fish from a relatively pristine site (Backdoor Bay, Cape Royds). Fish from both sites had similar liver concentrations of Zn, Cu and Cd and qcRT-PCR revealed similar levels of hepatic metallothionein mRNA. Ni in the livers of fish from Winter Quarters Bay were higher than those in fish from Backdoor Bay, but the differences were not great enough to affect hepatic metallothionein mRNA significantly. Despite the polluted state of Winter Quarters Bay waters, it seems that the heavy metals present may have only limited impact on the health status of fish collected from this locality. This may reflect a low bioavailability of the heavy metals in Ross Island marine sediments and suggests that other factors, such as relatively high levels of organic pollutants (PAHs, PCBs) or pathogens from the nearby sewage outlet, may play a more significant role in the aetiology of pathological conditions in fish from Winter Quarters Bay. [source] Variations in the contents of heavy metals in arable soils of a major urban wetland inlet drainage system of Lake Victoria, UgandaLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 2 2010Jolocam Mbabazi Abstract Little is known about the effects of urbanization on the chemical quality of soils in suburban wetland inlet drainage systems to the Uganda side of Lake Victoria, on which food crops are extensively grown. It is feared that pollution in the soils might eventually enter food chains through such crops being consumed by urban populations unaware of their occurrence. Soil samples were collected from cultivated areas of a major wetland drainage system (Nakivubo Channel), at Kampala, Ubanda, near Lake Victoria and from a rural control wetland site (Senge). The soil from this site had similar properties as those from the urban test site (i.e., soil texture; porosity; humus content). Analysis of heavy metals with atomic absorption spectrophotometry (AAS) yielded the following soil concentration ranges: manganese (190,780), cadmium (<0.001,1.0), zinc (6.0,10.0) and lead (10,20 mg kg,1) dry weight for the control site, and 450,900, 1.0,2.0, 131,185, 40,60 mg kg,1 dry weight, respectively, for the urban wetland, indicative of relatively heavy metal pollution in the suburban drainage system. Heavy metal levels in cocoyam (Colocasia Esculenta) and sugarcane (Saccharum Officinarum) grown on both wetland soils also were evaluated via AAS with a modified wet-acid-digestion technique. The results highlighted high cadium and lead levels (P , 0.0003) in the crops from urban wetland cultivation. Cadmium and lead concentrations in cocoyam from urban wetland soils exceeded those from the control site by 0.17 and 3.54 mg kg,1, respectively. The corresponding results for sugarcane indicated a similar increase of 0.56 and 2.14 mg kg,1 of juice extract. Cadmium and lead levels in both urban wetland crops were higher than the maximum permissible limits of the Codex Alimentarius Commission, indicating that these concentrations pose potential health risks to urban consumers, and call for early counter-measures to combat urban pollution entering the lake. [source] Heavy metal pollution in a sewage-fed lake of Bhopal, (M. P.) IndiaLAKES & RESERVOIRS: RESEARCH AND MANAGEMENT, Issue 1 2003Pradeep Shrivastava Abstract Shahpura Lake receives untreated domestic sewage from residential areas in Bhopal city. Analysis of water, plankton, fish and sediment reveals that the lake is contaminated by certain heavy metals. The concentrations of some of these metals including iron and manganese were within acceptable limits, whereas others including chromium, nickel, zinc and lead were not within acceptable water quality limits. Metal concentrations in the sewage inlet drain and lake sediment were compared with published criteria. The comparison revealed that the metals in the sediment ranged from the ,non-polluted' to the ,heavy pollution' categories. The reference dose was calculated by the adoption of the United States Environmental Protection Agency reference dose factor, and the result reveals that the local population is not exposed to undue health risks. Concentrations of heavy metals in the water increased during the second year of the study, indicating an increase in the pollution load on the system. This might increase the bioaccumulation levels in fish and increase the actual dose of metals to which the local population will be exposed. [source] Evaluation of extractable elements in artificial substratum made from sewage sludge: Approach to remediation of degraded land in the ArcticLAND DEGRADATION AND DEVELOPMENT, Issue 2 2009T. T. Gorbacheva Abstract The Arctic (or subarctic) is characterized by a harsh climate and nutrient-poor soil; what makes it even harsher in Monchegorsk (67°51,N and 32°48,E) is that metal pollution originating from the Ni,Cu smelting industry has severely damaged the soil and ground vegetation, resulting in formation of an industrial desert (barren ground). A pilot-scale (4,ha) field test was carried out under such conditions to study how to apply municipal sewage sludge for rehabilitation of degraded land. After sewage sludge had been composted, an artificial substratum made from the compost was introduced to the remediation test field, and then willow, birch and grasses were planted on the substratum. The transformation of the artificial substratum was observed in the test field during 3 years. The portion of Cu in residual form was greater than that in other forms, it is hence considered that Cu has low bioavailability in the artificial substratum. Furthermore, the metal distributions statistically increased in fractions of humic acid (insoluble in water under acidic conditions), so the mobile amounts of Ni and Cu became small. The conclusion drawn from the field survey and analysis of extractable metals indicates that the lost vegetation is being restored even while pollution continues to be discharged from the smelter operation. Copyright © 2008 John Wiley & Sons, Ltd. [source] Novel polymerase chain reaction primers for the specific detection of bacterial copper P-type ATPases gene sequences in environmental isolates and metagenomic DNALETTERS IN APPLIED MICROBIOLOGY, Issue 6 2010R. De la Iglesia Abstract Aims:, In the last decades, the worldwide increase in copper wastes release by industrial activities like mining has driven environmental metal contents to toxic levels. For this reason, the study of the biological copper-resistance mechanisms in natural environments is important. Therefore, an appropriate molecular tool for the detection and tracking of copper-resistance genes was developed. Methods and Results:, In this work, we designed a PCR primer pair to specifically detect copper P-type ATPases gene sequences. These PCR primers were tested in bacterial isolates and metagenomic DNA from intertidal marine environments impacted by copper pollution. As well, T-RFLP fingerprinting of these gene sequences was used to compare the genetic composition of such genes in microbial communities, in normal and copper-polluted coastal environments. New copper P-type ATPases gene sequences were found, and a high degree of change in the genetic composition because of copper exposure was also determined. Conclusions:, This PCR based method is useful to track bacterial copper-resistance gene sequences in the environment. Significance and Impact of the Study:, This study is the first to report the design and use of a PCR primer pair as a molecular marker to track bacterial copper-resistance determinants, providing an excellent tool for long-term analysis of environmental communities exposed to metal pollution. [source] Biological cost of tolerance to heavy metals in the mosquito Anopheles gambiaeMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2010P. O. MIREJI The global rate of heavy metal pollution is rapidly increasing in various habitats. Anopheles malaria vector species (Diptera: Culicidae) appear to tolerate many aquatic habitats with metal pollutants, despite their normal proclivity for ,clean' water (i.e. low levels of organic matter). Investigations were conducted to establish whether there are biological costs for tolerance to heavy metals in Anopheles gambiae Giles sensu stricto and to assess the potential impact of heavy metal pollution on mosquito ecology. Anopheles gambiae s.s. were selected for cadmium, copper or lead tolerance through chronic exposure of immature stages to solutions of the metals for three successive generations. Biological costs were assessed in the fourth generation by horizontal life table analysis. Tolerance in larvae to cadmium (as cadmium chloride, CdCl2), copper [as copper II nitrate hydrate, Cu(NO3)2 2.5 H2O] and lead [as lead II nitrate, Pb(NO3)2], monitored by changes in LC50 concentrations of the metals, changed from 6.07 µg/L, 12.42 µg/L and 493.32 µg/L to 4.45 µg/L, 25.02 µg/L and 516.69 µg/L, respectively, after three generations of exposure. The metal-selected strains had a significantly lower magnitude of egg viability, larval and pupal survivorship, adult emergence, fecundity and net reproductive rate than the control strain. The population doubling times were significantly longer and the instantaneous birth rates lower in most metal-selected strains relative to the control strain. Our results suggest that although An. gambiae s.s. displays the potential to develop tolerance to heavy metals, particularly copper, this may occur at a significant biological cost, which can adversely affect its ecological fitness. [source] Biodiversity conservation in Mediterranean and Black Sea lagoons: a trait-oriented approach to benthic invertebrate guildsAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2008A. Basset Abstract 1. The extent to which conservation of biodiversity enforces the protection of ecosystem functioning, goods and services is a key issue in conservation ecology. 2. In order to address this conservation issue, this work focused on community organization, linking community structure, as described both in taxonomic and functional terms, to community functioning and ecosystem processes. 3. Body size is an individual functional trait that is deterministically related to components of ecosystem functioning such as population dynamics and energy flow, and which determines components of community structure. Since body size is an individual trait that reflects numerous factors, it is also exposed to trait selection and the niche filtering underlying the community. 4. An analysis of the relevance of body size to community organization in transitional water ecosystems in the eastern Mediterranean and Black Sea regions is presented, based on field research conducted on a sample of 15 transitional water ecosystems. 5. 250 taxa were identified, clumped in five orders of magnitude of body size. All body size patterns showed triangular distributions with an optimal size range of 0.13 mg to 1.0 mg individual body mass. 6. Deterministic components of size structure were emphasized and a hierarchical organization with dominance of large sizes was demonstrated by the slopes of the body size-abundance distributions, consistently larger than the EER threshold (b=,0.75), and by the direct relationship of energy use to body size for most of the body size range. 7. Consistent variations of body size-related descriptors were observed on three main gradients of environmental stress: eutrophication, confinement and metal pollution. 8. The results support the relevance of constraints imposed by individual body size on community organization in transitional water ecosystems and the adequacy of size patterns as an indicator for ecological conservation of these fragile ecosystems. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||