Environmental contaminants in freshwater fish and their risk to piscivorous wildlife based on a national monitoring program

Organochlorine chemical residues and elemental concentrations were measured in piscivorous and benthivorous fish at 111 sites from large U.S. river basins. Potential contaminant sources such as urban and agricultural runoff, industrial discharges, mine drainage, and irrigation varied among the sampling sites. Our objectives were to provide summary statistics for chemical contaminants and to determine if contaminant concentrations in the fish were a risk to wildlife that forage at these sites. Concentrations of dieldrin, total DDT, total PCBs, toxaphene, TCDD-EQ, cadmium, chromium, mercury, lead, selenium, and zinc exceeded toxicity thresholds to protect fish and piscivorous wildlife in samples from at least one site; most exceedences were for total PCBs, mercury, and zinc. Chemical concentrations in fish from the Mississippi River Basin exceeded the greatest number of toxicity thresholds. Screening level wildlife risk analysis models were developed for bald eagle and mink using no adverse effect levels (NOAELs), which were derived from adult dietary exposure or tissue concentration studies and based primarily on reproductive endpoints. No effect hazard concentrations (NEHC) were calculated by comparing the NOAEL to the food ingestion rate (dietary-based NOAEL) or biomagnification factor (tissue-based NOAEL) of each receptor. Piscivorous wildlife may be at risk from a contaminant if the measured concentration in fish exceeds the NEHC. Concentrations of most organochlorine residues and elemental contaminants represented no to low risk to bald eagle and mink at most sites. The risk associated with pentachloroanisole, aldrin, Dacthal, methoxychlor, mirex, and toxaphene was unknown because NOAELs for these contaminants were not available for bald eagle or mink. Risk differed among modeled species and sites. Our screening level analysis indicates that the greatest risk to piscivorous wildlife was from total DDT, total PCBs, TCDD-EQ, mercury, and selenium. Bald eagles were at greater risk to total DDT and total PCBs than mink, whereas risks of TCDD-EQ, mercury, and selenium were greater to mink than bald eagle.     

Speciation of mercury in mine waste: case study of abandoned and active gold mine sites at the Bibiani–Anwiaso–Bekwai area of South Western Ghana

Speciation determines toxicity, transport pathways and residence time of a metal in different compartments of the environment. This study investigated the speciation of mercury in soils, derived from sites known for dumping of mine wastes in the Bibiani–Anwiaso–Bekwai district, a gold mining community of the Western Region of Ghana. Soil samples were taken from the surface; depths of 20, 40 and 60?cm from mine waste at both abandoned and active mine sites. Each sample was analysed for total mercury, organic mercury and elemental mercury. After sample treatment, digestion and reduction with stannous chloride (SnCl₂), total mercury content was determined using the Inductively Coupled Plasma—Optical Emissions Spectrometer (ICP–OES). Organic mercury content was determined employing a differential technique after disposing of elemental mercury by heating. Total mercury content in samples ranged from 0.067 to 0.876?mg/kg for surface soils. The same soil of depths 20, 40 and 60?cm had total mercury from 0.102 to 1.066, 0.037 to 4.037 and 0.191 to 4.998?mg/kg, respectively. For organic mercury, concentrations range from 0.012 to 0.260?mg/kg for surface soil. Soil depths of 20, 40 and 60?cm had organic mercury concentrations from 0.016 to 0.653, 0.041 to 1.093 and 0.101 to 2.546?mg/kg respectively. Elemental mercury concentrations in surface soils, soils at depths of 20, 40 and 60 cm ranged from 0.043 to 0.780; 0.017 to 0.749; 0.014 to 2.944 and 0.009 to 2.452 mg/kg respectively. Among the sites studied, only galamsey tailings (GM) showed a trend of increasing total mercury level with increasing depth. For the other sites, trends were not defined. There has been no defined trend for elemental mercury with depth at any of the sampling sites. Just as with total mercury, it was only GM that showed an increasing trend of organic mercury concentration with depth.     

The distribution and extent of heavy metal accumulation in song sparrows along Arizona’s upper Santa Cruz River

Heavy metals are persistent environmental contaminants, and transport of metals into the environment poses a threat to ecosystems, as plants and wildlife are susceptible to long-term exposure, bioaccumulation, and potential toxicity. We investigated the distribution and cascading extent of heavy metal accumulation in southwestern song sparrows (Melospiza melodia fallax), a resident riparian bird species that occurs along the US/Mexico border in Arizona’s upper Santa Cruz River watershed. This study had three goals: (1) quantify the degree of heavy metal accumulation in sparrows and determine the distributional patterns among study sites, (2) compare concentrations of metals found in this study to those found in studies performed prior to a 2009 international wastewater facility upgrade, and (3) assess the condition of song sparrows among sites with differing potential levels of exposure. We examined five study sites along with a reference site that reflect different potential sources of contamination. Body mass residuals and leukocyte counts were used to assess sparrow condition. Birds at our study sites typically had higher metal concentrations than birds at the reference site. Copper, mercury, nickel, and selenium in song sparrows did exceed background levels, although most metals were below background concentrations determined from previous studies. Song sparrows generally showed lower heavy metal concentrations compared to studies conducted prior to the 2009 wastewater facility upgrade. We found no cascading effects as a result of metal exposure.     

European bee-eater (Merops apiaster) populations under arsenic and metal stress: evaluation of exposure at a mining site

Two populations of the European bee-eater were studied, one living at a reference site and the other at a metal mining site. The concentration of arsenic and 11 metals (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) was measured in feathers and regurgitated pellets collected at both sites. Cadmium, chromium, mercury, nickel, and lead were at least twofold higher in feathers of birds from the contaminated site than in the reference site, suggesting that this population was exposed to higher metal levels. Similarly, levels of aluminum, arsenic, cadmium, cobalt, chromium, iron, and lead were also at least twofold higher in pellets from the contaminated area. The obtained results suggested that the impacted population of Merops apiaster is at risk due to the exposure to some metals.     

Accumulation and biological effects of metals in wild rats in mining areas of Zambia

The lead–zinc (Pb–Zn) mine in Kabwe City and the copper–cobalt (Cu–Co) mine in the Copperbelt Province are major mining areas in Zambia. To examine the effects of metal pollution on wildlife, wild black rats (Rattus rattus and Rattus tanezumi) were captured in Kabwe and Chingola (in the Copperbelt Province), and in Lusaka (a noncontaminated site). Wild black rats in Kabwe accumulated significantly higher concentrations of Pb and Cd in various organs than rats from Lusaka. In Chingola, significantly higher concentrations of Cu, Co, Pb, and Cd were accumulated in wild black rats than in rats from Lusaka. These results were in accordance with metal accumulation patterns in soil. From toxicological aspects, concentrations of Pb and Cd in rats were generally low. However, metallothionein-1 (MT-1) and metallothionein-2 (MT-2) mRNA expression levels in wild black rats from Kabwe were significantly higher than those in rats from Lusaka. A generalized linear model (GLM) showed that concentrations of Zn and Cu had positive effects on the MT-1 and MT-2 mRNA expression. These results suggest that wild black rats in Zambian mining sites were exposed to metals that accumulated in their organs, causing biological responses such as MT mRNA induction. GLM indicated that heme oxygenase-1 (HO-1) mRNA expression could be a marker for Cr exposure.     

Metal accumulation in the tissues of grass carps (Ctenopharyngodon idellus) from fresh water around a copper mine in Southeast China

Mining effluents are the main source of metals in the surrounding aquatic environment. The mining district of Purple Mountain has a history of copper mining for more than 30 years, but there is limited investigation of metal bioaccumulation in the aquatic creatures from the Tingjiang river catchment affected by the mining activities. In this study, we collected grass carps (Ctenopharyngodon idellus) from four sites, and analyzed the accumulation of chromium (Cr), nickel (Ni), manganese (Mn), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) in ten tissues (scale, skin, muscle, gill, liver, kidney, fish maw, heart, stomach, and intestine) of the fish samples. Among all tissue samples, the highest concentrations (micrograms per gram wet weight) of Ni (0.263), Cu (69.2), Zn (84.0), As (0.259), Cd (0.640), Hg (0.051), and Pb (0.534) were noted in the liver, gill, and kidney tissues, whereas the highest concentrations of Cr (0.356) and Mn (62.7) were detected in the skin and intestine, respectively. These results gave a better understanding of the variability of metals distribution in different fish tissues. In comparison with the sample sites, metals (especially Mn, Cu, Zn, Ni, and Pb) in liver, gill, kidney, stomach, and intestine showed more inter-site differences than other tissues. The inter-site differences also revealed that site 1 and 2 increased fish uptake of Cu, Zn, Ni, and Pb, which may indicate that the copper mine and urban effluents contributed to high levels of these metals in aquatic environments in site 1 and 2. A potential food safety issue may emerge depending on the mining activities in this region because some metals in a few tissue samples exceeded the guideline values for human consumption of fish.     

Ecotoxicological Assessment of the Impact of Residual Heavy Metals on Soil Nematodes in the Guadiamar River Basin (Southern Spain)

On 25 April 1998, as a consequence of the breaking of a dam containing the tailings of a pyrite mine, a land strip of approximately 43 km in length was covered with a layer of black sludge, containing high levels of heavy metals, along the Guadiamar River Basin (southern Spain). In this investigation we carried out an ecotoxicological assessment (field and laboratory studies) of the impact of residual heavy metals (Cu, Pb, Zn, Ni) on soil nematodes in the impacted riparian zone, two years after the huge mine spillage. Concentrations of residual heavy metals were significantly (P<0.05) higher at the impacted sampling sectors (S-2, S-3, S-4, S-5) than at the unpolluted (reference) sampling sector (S-1). Nickel however exhibited the lowest increases at the impacted sectors. As a consequence, correlation coefficients between concentrations of heavy metals and values of ecological indices were not significant for Ni. In contrast, copper, lead and zinc exhibited significant (P<0.05) negative correlation coefficients with ecological indices, particularly with diversity indices (including the~number of taxa). In addition, the toxicity of Cu and Pb to nematode test species (Aphelenchus avenae and Cephalobus persegnis) during short-term toxicity bioassays was much higher than the toxicity of Zn and Ni. We conclude that residual heavy metals were still influencing adversely the community of soil nematodes in the impacted riparian zone of the Guadiamar River Basin. Cu, Pb and, to a lesser extent, Zn would be major responsible for the observed impact.     

Interspecific and Locational Differences in Heavy Metal Levels in Four Species of Birds Near Sydney, Australia

We examined the levels of cadmium, chromium, lead, manganese, mercury, and selenium in four species of birds near Sydney, New South Wales, Australia in January, 1996. Molted contour feathers were collected from silver gull, Larus novaehollandiae (Royal National Park and downtown Sydney), sulphur-crested cockatoo, Cacatua sulphurea (Blue Mountains, Royal National Park, and Sydney), Australian white ibis, Threskiornis molucca (Sydney), and rock dove Columba livia (Royal National Park and Sydney). We tested the null hypothesis that there were no species or locational differences in metal levels. There were significant species differences in all metals, with rock doves having the highest levels of cadmium, chromium, lead, and manganese, and silver gulls having the highest levels of mercury and selenium. Metal levels were generally low in cockatoos, and were lowest in those from the Royal National Park. For silver gulls, cadmium, lead, and chromium levels were highest at Sydney, and there were no locational differences in manganese, mercury, and selenium levels. For rock doves, cadmium, chromium and manganese were higher in Sydney, and there were no locational differences in lead, mercury, and selenium. Overall, cadmium and chromium levels were significantly higher in Sydney than in the Royal National Park for all species, and there were no locational differences in mercury levels. Although the levels of most metals in feathers from these Australian birds were within the ranges reported worldwide, lead levels in ibises and rock doves were among the highest reported worldwide, suggesting a cause for concern.     

海南昌江石碌钴铜矿尾矿库重金属污染环境现状调查

为了解海南省昌江县石碌镇钴铜矿尾矿库环境特点,分别采集了矿砂、背景土壤、废水、纳污水体和植物进行分析。结果表明,钴铜矿尾矿库的土壤受As和Cu污染严重,周边土壤受到不同程度的重金属污染;废水经过尾矿库沉淀处理后,SS、As、Cu、Co、Fe等监测指标均有所降低,尾矿库起到沉淀吸附处理作用;纳污河流石碌河水质良好;尾矿库内自然生长的菖蒲和水竹均受到重金属不同程度污染,尾矿库内的甘蔗中Cr、Pb含量均超过食品中污染物限量标准,表明尾矿库内不宜种植可食用作物。     

Biomonitoring of Lead, Zinc, and Cadmium in Streams Draining Lead-Mining and Non-Mining Areas, Southeast Missouri, USA

We evaluated exposure of aquatic biota to lead (Pb), zinc (Zn), and cadmium (Cd) in streams draining a Pb-mining district in southeast Missouri. Samples of plant biomass (detritus, periphyton, and filamentous algae), invertebrates (snails, crayfish, and riffle benthos), and two taxa of fish were collected from seven sites closest to mining areas (mining sites), four sites further downstream from mining (downstream sites), and eight reference sites in fall 2001. Samples of plant biomass from mining sites had highest metal concentrations, with means 10- to 60-times greater than those for reference sites. Mean metal concentrations in over 90% of samples of plant biomass from mining sites were significantly greater than those from reference sites. Mean concentrations of Pb, Zn, and Cd in most invertebrate samples from mining sites, and mean Pb concentrations in most fish samples from mining sites, were also significantly greater than those from reference sites. Concentrations of all three metals were lower in samples from downstream sites, but several samples of plant biomass from downstream sites had metal concentrations significantly greater than those from reference sites. Analysis of supplemental samples collected in the fall of 2002, a year of above-average stream discharge, had lower Pb concentrations and higher Cd concentrations than samples collected in 2001, near the end of a multi-year drought. Concentrations of Pb measured in fish and invertebrates collected from mining sites during 2001 and 2002 were similar to those measured at nearby sites in the 1970s, during the early years of mining in the Viburnum Trend. Results of this study demonstrate that long-term Pb mining activity in southeast Missouri has resulted in significantly elevated concentrations of Pb, Cd, and Zn in biota of receiving streams, compared to biota of similar streams without direct influence of mining. Our results also demonstrate that metal exposure in the study area differed significantly among sample types, habitats, and years, and that these factors should be carefully considered in the design of biomonitoring studies.     

Non-radiological contaminants from uranium mining and milling at Ranger,Jabiru, Northern Territory,Australia

Protection from the hazards from radioactivity is of prime importance in the management of uranium mine and mill wastes. Such wastes also contain non-radiological contaminants (heavy metals, acids and neutralising agents) which give rise to potential long-term health and environmental hazards and short-term hazards to the aquatic ecosystem, e.g. as a result of release of waste water. This study seeks to identify non-radiological contaminants (elements) transferred to waste water at the Ranger uranium mine/mill complex at Jabiru, which are likely to hazardous to the aquatic environment. The two principal sources of contaminants are:

1. ore and waste rock mobilised from mining; and
2. process reagents used in the milling and mineral extraction process.

These substances may or may not already be present in the natural environment but may lead to deleterious effects on the aquatic environment if increased above threshold levels. Rhenium, derived from the ore body, was found to be significantly enriched in waste water from Ranger, indicating its suitability as an indicator element for water originating from the mining and milling process, but only uranium, likewise derived from the ore, and magnesium, manganese and sulfur (as sulfate) from the milling process were found to be significant environmental contaminants.     

Biomarker responses of <Emphasis Type="Italic">Peromyscus leucopus</Emphasis> exposed to lead and cadmium in the Southeast Missouri Lead Mining District

Biomarker responses and histopathological lesions have been documented in laboratory mammals exposed to elevated concentrations of lead and cadmium. The exposure of white-footed mice (Peromyscus leucopus) to these metals and the potential associated toxic effects were examined at three contaminated sites in the Southeast Missouri Lead Mining District and at a reference site in MO, USA. Mice from the contaminated sites showed evidence of oxidative stress and reduced activity of red blood cell δ-aminolevulinic acid dehydratase (ALAD). Histological examinations of the liver and kidney, cytologic examination of blood smears, and biomarkers of lipid peroxidation and DNA damage failed to show indications of toxic effects from lead. The biomagnification factor of cadmium (hepatic concentration/soil concentration) at a site with a strongly acid soil was 44 times the average of the biomagnification factors at two sites with slightly alkaline soils. The elevated concentrations of cadmium in the mice did not cause observable toxicity, but were associated with about a 50% decrease in expected tissue lead concentrations and greater ALAD activity compared to the activity at the reference site. Lead was associated with a decrease in concentrations of hepatic glutathione and thiols, whereas cadmium was associated with an increase. In addition, to support risk assessment efforts, we developed linear regression models relating both tissue lead dosages (based on a previously published a laboratory study) and tissue lead concentrations in Peromyscus to soil lead concentrations.     

Heavy metal concentrations in groundwaters and soils of Thane Region of Maharashtra, India

Thane district is one of the most industrialized districts in Maharashtra. The heavy industrialization and the increasing urbanization are responsible for the rapidly increasing stress on the water and soil environment of the area. Therefore, an attempt has been made through comprehensive study on the groundwater contamination and soil contamination due to heavy metals in Thane region of Maharashtra. The area undertaken for the study was Thane and its suburbans Kalwa, Divajunction, Dombivali, Kalyan, and Ulhasnagar. Industrialization and urbanization lead to generation of large volumes of wastewater from domestic, commercial, industrial, and other sources, which discharged in to natural water bodies like river and creek in this region. Groundwater samples and soil samples were collected from residential, commercial, agriculture, and industrial areas. Groundwater samples were analyzed for various water quality parameters. The analytical data shows very high concentration of total dissolved solids, total hardness, total alkalinity, chemical oxygen demand, chloride etc. Groundwater and soil samples were analyzed for ten heavy metals by inductively coupled plasma (ICPE-9000) atomic emission spectroscopy. The analytical data reveal that, very high concentration level of arsenic, cadmium, mercury, and nickel throughout the industrial area. The random dumping of hazardous waste in the industrial area could be the main cause of the groundwater and soil contamination spreading by rainwater and wind. In the residential areas the local dumping is expected to be the main source for heavy metals. A comparison of the results of groundwater with WHO guidelines show that most of the groundwater sampling station are heavily contaminated with organic matter and heavy metals. Groundwater samples are heavily contaminated by arsenic, cadmium, mercury, and nickel. Similarly, the results of heavy metals in soil compared with Swedish soil guideline values for polluted soil show that soil samples collected from residential, commercial and industrial areas are heavily contaminated by arsenic, cadmium, mercury, and nickel.     

真藓对碳酸盐型锰矿区重金属污染的指示意义

锰矿开采产生重金属污染,对周围环境造成影响,有必要对矿区重金属进行监测。研究以典型碳酸盐型锰矿——南茶锰矿(按职能划分为4个功能区:矿井区、废石区、选矿区、蓄矿区)为对象,以区域内真藓Bryum argenteum为材料,结合相关分析、聚类分析、主成分分析、变异系数等方法考察了真藓和土壤中重金属的含量及其可能的来源。结果表明:各功能区均受到不同程度的人为干扰,人为干扰越强,区域污染越严重。在不同污染梯度的功能区内,真藓的重金属(Fe、Mn、Zn、Cr、Ni、Ba、Co、Mo、Hg、Pb、Cd、Cu、Tl、As、Sb)含量与土壤重金属含量显著正相关(P<0.05),说明真藓是监测碳酸盐型锰矿重金属污染的有效指标。真藓指示南茶锰矿除了可能受到采矿活动的强烈影响外(Mn、Cu、Fe、Zn、Cr、Ni、Mo、Ba),还受到来自运输车辆的机械磨损、排放及采矿活动的复合污染(Tl、Cd、Pb、As、Sb),识别结果与区域重金属分布情况吻合,表明真藓具有识别重金属污染的能力。在今后碳酸盐型锰矿污染防治工作中,可将真藓作为重金属污染监测的生物材料。     

Risks associated with the mining of Pb–Zn minerals in some parts of the Southern Benue trough,Nigeria

The environmental effects of the mining of lead–zinc mineralization in Enyigba area, Southern Benue trough were examined. The samples used for this study were obtained from abandoned mine sites, mine tailings, streams, hand-dug wells, mine pond and borehole. Collected samples were subjected to X-ray fluorescence, X-ray diffraction analyses, atomic absorption spectrometry and permeability tests. These were done using standard laboratory equipment and procedures. The concentrations of heavy metals present in analysed water samples fall below the world health organizations’ (WHO) acceptable limits. Conversely, the soil, mine tailings and stream sediments indicate appreciable pollution level by some potential toxic metals (PTMs). Consequently, the habitual use of these soils for construction purpose by inhabitants has possible health hazards. The shaly lithology underlying the area is increasingly affected by weathering and lateritization, thus improving its permeability and the easiness with which PTMs can be conducted to the water table by leachate. Regular monitoring assessment is recommended to ensure adherence of miners operating in the area to existing environmental laws.     

Risk assessment of soils contaminated by mercury mining, Northern Spain

Analytical results of soil samples taken in three different mercury mining sites in Northern Spain are studied to assess the potential adverse health effects of the exposure to trace elements associated with the mining process. Doses contacted through ingestion and inhalation and the dose absorbed through the skin were calculated using USEPA's exposure parameters and the US Department of Energy's toxicity values. The results of the risk assessment indicate that the highest risk is associated with ingestion of soil particles and that the trace element of major concern is arsenic, the exposure to which results in a high cancer risk value for all the sites ranging from 3.3 × 10(-5) to 3.6 × 10(-3), well above the 1 × 10(-5) probability level deemed unacceptable by most regulatory agencies. Regarding non-cancer effects, exposure to polluted soils yields an aggregate hazard index above the threshold value of 1 for all three sites, with As and Hg as the main contributors. Risk assessment has proven to be a very useful tool to identify the contaminants and exposure pathways of most concern in the soils from metal mining sites, as well as to categorize them in terms of action priority to ensure fitness for use.     

Occurrence of phthalic acid esters in Gomti River Sediment, India

Cadmium and lead are important environmental pollutants with high toxicity to animals and human. Soils, though have considerable metal immobilizing capability, can contaminate food chain via plants grown upon them when their built-up occurs to a large extent. Present experiment was carried out with the objective of quantifying the limits of Pb and Cd loading in soil for the purpose of preventing food chain contamination beyond background concentration levels. Two separate sets of pot experiment were carried out for these two heavy metals with graded levels of application doses of Pb at 0.4–150 mg/kg and Cd at 0.02–20 mg/kg to an acidic light textured alluvial soil. Spinach crop was grown for 50 days on these treated soils after a stabilization period of 2 months. Upper limit of background concentration levels (C _ul) of these metals were calculated through statistical approach from the heavy metals concentration values in leaves of spinach crop grown in farmers’ fields. Lead and Cd concentration limits in soil were calculated by dividing C _ul with uptake response slope obtained from the pot experiment. Cumulative loading limits (concentration limits in soil minus contents in uncontaminated soil) for the experimental soil were estimated to be 170 kg Pb/ha and 0.8 kg Cd/ha. Based on certain assumptions on application rate and computed cumulative loading limit values, maximum permissible Pb and Cd concentration values in municipal solid waste (MSW) compost were proposed as 170 mg Pb/kg and 0.8 mg Cd/kg, respectively. In view of these limiting values, about 56% and 47% of the MSW compost samples from different cities are found to contain Pb and Cd in the safe range.     

湖北省重点区域及周边表层土壤重金属污染现状及评价

对湖北省内9类不同重点区域及周边表层土壤环境质量进行检测,测定重金属镉、汞、砷、铅、铬、铜、镍、锌含量水平,采用内梅罗污染指数法和Hakanson潜在生态风险指数法对检测结果进行评价。结果表明:9类不同重点区域及周边土壤环境质量整体良好,未受重金属污染的土壤监测点位比例为68.2%~92.6%,轻度污染的点位比例为5.8%~20.4%,中度污染为0.0%~8.6%,重度污染为0.0%~9.1%;污染企业周边、油田采矿区周边、固废处置场地周边、工业遗留遗弃场地及周边4类重点区域受重金属污染相对较严重,影响其土壤环境质量的重金属主要是镉、砷、铜、铅;9类不同重点区域周边土壤环境质量的潜在生态风险等级以轻微、中度为主,对应的监测点位比例分别为36.4%~80.5%、18.1%~47.7%,潜在生态风险等级为强度、很强、极强的监测点位比例总和为1.4%~15.9%,主要分布在受重金属污染严重的监测区域。     

基于双指标多等级的土壤重金属生态风险评价

采用土壤中重金属的全量和有效态双重指标,建立基于多等级综合评估的土壤中重金属生态风险评价模型,将联合概率曲线法引入土壤评价模型,分析重金属暴露浓度与毒性数据的概率分布,考察重金属对土壤生物的毒害程度,从而确定土壤中重金属对于生态系统的风险。建立从简单到复杂的多等级综合评价方法,表征重金属的污染等级、浓度效应、多种重金属污染物的协同效应、不同重金属的毒性效应和土壤对不同重金属污染物的敏感性。选择典型地区采集有代表性的土壤样品,测定不同重金属的总量和有效态,验证评价模型的实用性和评价分级的合理性。旨在解决土壤重金属风险评价的方法学问题,为土壤环境质量管理提供支持。     

Geochemical position of Pb,Zn and Cd in soils near the Olkusz mine/smelter,South Poland: effects of land use,type of contamination and distance from pollution source

The soils adjacent to an area of historical mining, ore processing and smelting activities reflects the historical background and a mixing of recent contamination sources. The main anthropogenic sources of metals can be connected with historical and recent mine wastes, direct atmospheric deposition from mining and smelting processes and dust particles originating from open tailings ponds. Contaminated agriculture and forest soil samples with mining and smelting related pollutants were collected at different distances from the source of emission in the Pb–Zn–Ag mining area near Olkusz, Upper Silesia to (a) compare the chemical speciation of metals in agriculture and forest soils situated at the same distance from the point source of pollution (paired sampling design), (b) to evaluate the relationship between the distance from the polluter and the retention of the metals in the soil, (c) to describe mineralogy transformation of anthropogenic soil particles in the soils, and (d) to assess the effect of deposited fly ash vs. dumped mining/smelting waste on the mobility and bioavailability of metals in the soil. Forest soils are much more affected with smelting processes than agriculture soils. However, agriculture soils suffer from the downward metal migration more than the forest soils. The maximum concentrations of Pb, Zn, and Cd were detected in a forest soil profile near the smelter and reached about 25 g kg^− 1, 20 g kg^− 1 and 200 mg kg^− 1 for Pb, Zn and Cd, respectively. The metal pollutants from smelting processes are less stable under slightly alkaline soil pH then acidic due to the metal carbonates precipitation. Metal mobility ranges in the studied forest soils are as follows: Pb > Zn ≈ Cd for relatively circum-neutral soil pH (near the smelter), Cd > Zn > Pb for acidic soils (further from the smelter). Under relatively comparable pH conditions, the main soil properties influencing metal migration are total organic carbon and cation exchange capacity. The mobilization of Pb, Zn and Cd in soils depends on the persistence of the metal-containing particles in the atmosphere; the longer the time, the more abundant the stable forms. The dumped mining/smelting waste is less risk of easily mobilizable metal forms, however, downward metal migration especially due to the periodical leaching of the waste was observed.