刁江沿岸土壤重金属污染状况及土地的合理利用模式

目的了解刁江沿岸土壤重金属污染区分布,寻求安全的污染区土地利用模式。方法于2003年在刁江沿岸设置了12个采样断面,采样分析土壤中重金属含量,分析了污染区大米、玉米和桑叶中的重金属(As,Pb,Cd、Zn)含量。结果土壤中的主要污染物为As(19.6～7441mg/kg)、Pb(53.4～1823mg/kg)、Cd(0.35～39.2mg/kg)、Zn(110～4199mg/kg)等,污染区范围与洪水淹没区一致。污染耕地上产出的大米中Cd和Pb含量超过国家食品卫生标准,尤其是大米中Cd的含量超标4.9倍,Pb超标0.905倍;玉米中Pb、Cd和Zn的含量分别超标1.345倍,0.56倍和0.598倍。结论受上游矿山开发影响,刁江沿岸土壤重金属污染十分严重,建议将污染区耕地划定为食用农作物禁止种植区,在污染区开展种桑养蚕试验,将严重尾砂覆盖污染区作为尾砂库并进行植被恢复与重建。     

Comparative assessment of soil contamination by lead and heavy metals in riparian and agricultural areas (southern Québec, Canada)

Soils contaminated with hydrocarbons (C(10)-C(50)), PAHS, lead and other heavy metals were recently found in the banks of two major rivers in southern Québec. Alluvial soils are contaminated over a distance of 100 kilometers. Eight sampling sites, including some located in agriculture areas (farm woodlots) have been selected to compare air pollution (aerosol fallout and rainout) and river pollution values. The concentrations detected in soil profiles for As, Cd and Pb vary between 3.01 to 37.88 mg kg(-1) (As), 0.11 to 0.81 mg kg(-1) (Cd) 12.32 to 149.13 mg kg(-1) (Pb). These metallic elements are considered highly toxic and can harm wildlife and human health at high levels. The maximum concentration of Pb (149.13 mg kg(-1)) in soils of the riparian zone is twelve times higher than the average Pb concentration found in a natural state evaluated at 15.3 mg kg(-1) (SD 17.5). Pb concentrations in soils of agricultural areas (woodland control sites) range between 12 and 22 mg kg(-1), and given that these values are recorded in surrounding cultivated land, the issue of the quality of agricultural products (crops and forage) to feed livestock or destined for human consumption must be further addressed in detail.     

Heavy-Metal Concentrations in Small Mammals from a Diffusely Polluted Floodplain: Importance of Species- and Location-Specific Characteristics

The soil of several floodplain areas along large European rivers shows increased levels of heavy metals as a relict from past sedimentation of contaminants. These levels may pose risks of accumulation in food webs and toxicologic effects on flora and fauna. However, for floodplains, data on heavy-metal concentrations in vertebrates are scarce. Moreover, these environments are characterised by periodical flooding cycles influencing ecologic processes and patterns. To investigate whether the suggested differences in accumulation risks for insectivores and carnivores, omnivores, and herbivores are reflected in the actual heavy-metal concentrations in the species, we measured the current levels of Zn, Cu, Pb, and Cd in 199 specimens of 7 small mammal species (voles, mice, and shrews) and in their habitats in a diffusely polluted floodplain. The highest metal concentrations were found in the insectivorous and carnivorous shrew, Sorex araneus. Significant differences between the other shrew species, Crocidura russula, and the vole and mouse species was only found for Cd. The Cu concentration in Clethrionomys glareolus, however, was significantly higher than in several other vole and mouse species. To explain the metal concentrations found in the specimens, we related them to environmental variables at the trapping locations and to certain characteristics of the mammals. Variables taken into account were soil total and CaCl₂-extractable metal concentrations at the trapping locations; whether locations were flooded or nonflooded; the trapping season; and the life stage; sex; and fresh weight of the specimens. Correlations between body and soil concentrations and location or specimen characteristics were weak. Therefore; we assumed that exposure of small mammals to heavy-metal contamination in floodplains is significantly influenced by exposure time, which is age related, as well as by dispersal and changes in foraging and feeding patterns under influence of periodic flooding.     

Use of crayfish in biomonitoring studies of environmental pollution of the river Meuse

The river Meuse, located in western Europe, is contaminated by different pollutants, of both organic and inorganic nature. The predominant sources of Meuse contamination in The Netherlands are agricultural activities and pollution derived from urban areas. Crayfish, water, and sediment samples were collected at four different locations of the river Meuse, in order to cover a large part of the catchment area of this river in The Netherlands. Crayfish may be very useful in biomonitoring studies, since they can integrate body load by pollutants over time in an area-bound manner. In these crayfish, levels of aromatic DNA adducts, heavy metal residues, polychlorinated biphenyls (PCBs), and organochlorine pesticides were determined in hepatopancreatic tissue. Also analyzed were water and sediment samples derived from the same locations, for polycyclic aromatic hydrocarbons (PAHs), heavy metals, and organochlorine compounds. In sediments from the four different sampling sites, no clear differences were observed in PCB levels. Organochlorine pesticide concentrations were highest at location A, the most upstream sampling site, whereas a general decrease was observed following the river Meuse downstream. A similar pattern was observed for the metal compounds. For PAH sediment levels no consistent tendency could be observed. Highest values were detected at site B, followed by, respectively, locations A, D, and C. In water samples, a different pattern was observed. The highest metal concentration was observed at location D, whereas the total organochlorine level was higher at sites B and D, compared to the two other sampling sites. Differences in pollution levels in crayfish between sampling sites were evident. Site D, the most downstream-situated site examined, appeared to be the most polluted site with respect to PCBs, DDT, DDE, and Cu in crayfish. Moreover, DNA adduct levels, which may serve as a dosimeter for the internal dose of aromatic compounds such as PAHs and PCBs, were also significantly higher in hepatopancreatic tissue of crayfish captured at site D, compared to the three other sampling sites. Moreover, significant correlations were observed between DNA adduct levels and the lower chlorinated PCB congeners (PCB 28-PCB 101). By correlating the different pollutants in water and/or sediment with xenobiotic levels in crayfish, no consistency could be observed, indicating that monitoring aquatic species may provide specific information on the presence of surface water pollutants. These results indicate that crayfish can be used as biological indicators of exposure to both organic and inorganic pollution in aquatic systems.     

Assessing arsenic,cadmium, and lead contents in major crops in Brazil for food safety purposes

The food chain is one of the major sources of human exposure to non-essential trace elements (TEs) present in soils. Human exposure to contaminated food is a worldwide health concern and a food safety issue that threatens agricultural trade. To assess the quality of Brazilian food products with respect to non-essential TEs, we evaluated arsenic (As), cadmium (Cd), and lead (Pb) contents in five major crops grown in Brazil: rice, wheat, corn, soybeans, and potatoes. The samples were collected from field trials with a record of long-term use of phosphate fertilizers in the states of Mato Grosso and Minas Gerais, Brazil. The TE concentrations in soils were all bellow the maximum allowable concentrations for agricultural soils. The mean concentrations of As, Cd, and Pb (μg kg⁻¹ dry weight) were as follows: below the detection limit <15, 29, and <40 for rice; 19, 23, and 64 for wheat; 47, 40, and 95 for corn; 65, 23, and 106 for soybeans; and 59, 22, and <40 for potatoes, respectively. Significant differences were found in the As and Cd contents of the different wheat cultivars. The levels of As, Cd, and Pb found in the studied crops are well below the values reported in the literature and are in accordance with the Codex Alimentarius and the European Union and Brazilian guidelines, indicating that the concentrations of these elements in the crops do not pose a risk to human health.     

Human health risk assessment in relation to environmental pollution of two artificial freshwater lakes in The Netherlands.

A human health risk assessment has been performed in relation to recreational activities on two artificial freshwater lakes along the river Meuse in The Netherlands. Although the discharges of contaminants into the river Meuse have been reduced in the last decades, which is reflected in decreasing concentrations of pollutants in surface water and suspended matter, the levels in sediments are more persistent. Sediments of the two freshwater lakes appear highly polluted and may pose a health risk in relation to recreational activities. To quantify health risks for carcinogenic (e.g., polycyclic aromatic hydrocarbons) as well as noncarcinogenic compounds (e.g., heavy metals), an exposure assessment model was used. First, we used a standard model that solely uses data on sediment pollution as the input parameter, which is the standard procedure in sediment quality assessments in The Netherlands. The highest intake appeared to be associated with the consumption of contaminated fish and resulted in a health risk for Pb and Zn (hazard index exceeded 1). For the other heavy metals and for benzo(a)pyrene, the total averaged exposure levels were below levels of concern. Secondly, input data for a more location-specific calculation procedure were provided via analyses of samples from sediment, surface water, and suspended matter. When these data (concentrations in surface water) were taken into account, the risk due to consumption of contaminated fish decreased by more than two orders of magnitude and appeared to be negligible. In both exposure assessments, many assumptions were made that contribute to a major degree to the uncertainty of this risk assessment. However, this health risk evaluation is useful as a screening methodology for assessing the urgency of sediment remediation actions.     

Assessment of lead, cadmium, and zinc contamination of roadside soils, surface films, and vegetables in Kampala City, Uganda

The relationship between traffic density and trace metal concentrations in roadside soils, surface films, and a selected vegetable weed, Amaranthus dubius Mart. Ex Thell., was determined in 11 farming sites along major highways around Kampala City in Uganda. Surface soil, atmospherically deposited surface films on windows, and leaves of Amaranthus dubius were sampled at known distances from the roads and analyzed for lead (Pb), zinc (Zn), and cadmium (Cd) using flame atomic absorption spectrophotometry. Atmospherically deposited trace metal particulates were sampled using window glass as an inert, passive collector. Total trace metal concentrations in soils ranged from 30.0+/-2.3 to 64.6+/-11.7 mg/kg Pb, 78.4+/-18.4 to 265.6+/-63.2 mg/kg Zn, and 0.8+/-0.13 to 1.40+/-0.16 mg/kg Cd. Total trace metal levels in soil decreased rapidly with distance from the road. Total Pb decreased with distance up to 30 m from the road, where it reached a background soil concentration of 28 mg/kg dry weight. The study found background values of 50 and 1.4 mg/kg for Zn and Cd in roadside soils, respectively. Similarly, Pb concentration in Amaranthus dubius leaves decreased with increasing distance from the road edge. The dominant pathway for Pb contamination was from atmospheric deposition, which was consistent with Pb concentrations in surface films. The mean Pb concentrations in leaves of roadside crops were higher than those in their respective roots, with the highest leaf-to-root ratio observed in the Brassica oleraceae acephala group. The lowest Pb and Zn concentrations were found in the fruit compared to the leaves of the same crops. Leaves of roadside vegetables were therefore considered a potential source of heavy metal contamination to farmers and consumers in urban areas. It is recommended that leafy vegetables should be grown 30 m from roads in high-traffic, urban areas.     

Effect of Cd or Pb Addition to Cu-Contaminated Soil on Tissue Cu Accumulation in the Earthworm,Dendrobaena veneta

Generally, soil heavy metal contamination consists of a mixture of heavy metals. Soil chemical properties and interaction with other pollutants in soil affect the external heavy metal bioavailability. Moreover, interaction with other pollutants accumulated in organisms may change the toxicity of each pollutant. Therefore, the hypotheses was tested that addition of Cd or Pb to Cu-contaminated soil would lead to an increase in tissue Cu accumulation in the earthworm,Dendrobaena veneta,caused by (i) induction of metallothionein by Cd, or (ii) an increase in Cu concentration in soil solution due to the exchange of adsorbed Cu for Pb. Tissue heavy metal concentrations were determined after exposure in contaminated soils for 3 or 21 days. Considerable amounts of Cu, Cd, and Pb were accumulated, indicating that these heavy metals were available for uptake byD. veneta.Both Cd and Pb, however, did not significantly affect tissue Cu accumulation.     

Combined Amendments of Nano-hydroxyapatite Immobilized Cadmium in Contaminated Soil-Potato (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) System

The toxicity of cadmium (Cd) has posed major public health concern in crops grown in the Cd-contaminated soils. The effects of five amendments, nano-hydroxyapatite (n-HA) and it combined with lime, zeolite, bone mill and fly ash on Cd immobilization in soils and uptake in potatoes, were investigated in a contaminated soil by pot experiments. The result showed that the applications of combined amendments significantly decreased the bioavailable Cd concentrations extracted by TCLP, DTPA–TEA and MgCl₂ in the contaminated soils, and changed the soluble and exchangeable and specifically sorbed fractions to oxide-bound and organic-bound fractions. Compared to the control group, the concentrations of Cd in the potato tubers grown in n-HA, n-HA?+?Fly ash, n-HA?+?Lime, n-HA?+?Bone mill and n-HA?+?Zeolite soil were reduced 17.4%, 20.7%, 15.2%, 32.6% and 39.1%, respectively. Nano-hydroxyapatite combined amendments was more effective in reducing bioavailable Cd concentrations and Cd accumulations in potatoes, especially for n-HA?+?Z.     

Environmental cadmium exposure induces alterations in the urinary metabolic profile of pregnant women

Cadmium (Cd) is a well-recognized, hazardous toxic heavy metal, and the adverse effects of high-level Cd exposure on human health have been well documented. However, little is known about the health effects of low-level environmental Cd exposure on pregnant women. The objective of this study was to assess urinary metabolic alterations in pregnant women exposed to environmental Cd, and to identify informative biomarkers. Urine samples from 246 pregnant women in the first trimester of pregnancy were collected, and urinary Cd concentrations were quantified using inductively coupled plasma mass spectrometry (ICP-MS). Urinary metabolomics was analyzed by ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Cd-related metabolic biomarkers were examined by comparing the samples of the first and third tertiles of Cd exposure classifications, using a partial least-squares discriminant (PLS-DA) model. Five putative biomarkers were identified, including L-cystine, L-tyrosine, dityrosine, histamine, and uric acid, all of which were related to oxidative stress and nephrotoxic effects induced by Cd exposure. The results show that low-level environmental Cd exposure could induce metabolite profile alterations in pregnant women, which might be associated with adverse health effects. Our findings provide new insights into the early molecular events following Cd exposure, and may be valuable for the health risk assessment of Cd exposure during pregnancy.     

Heavy metal pollution of river Yamuna in the industrially developing state of Haryana

Heavy metal concentrations viz. Fe, Ni, Pb, Cd, Co, Zn in the river Yamuna flowing along the state of Haryana through Delhi have been reported selecting 16 stations covering the upstream and downstream stations for major industrial complexes of the state. While Fe, Ni and Co concentrations exceeded the maximum permissible limits prescribed for drinking all along the river, the Cd concentrations crossed the acceptable standards in Delhi downstream. The Pb concentrations declined in the eutrophicated Delhi downstream while Zn concentrations remained within desirable limits throughout. Peak concentrations were recorded in Delhi downstream for Fe and at Sonepat-Gohana downstream for Ni, Co & Zn, which matched with the type of industrial inputs viz. Iron-works and the electroplating, galvanizing & cycle industries, respectively. The status of heavy metal pollution of the river has been discussed with respect to possible impacts on human health and aquatic life.     

底泥重金属镉对鳙鱼血细胞微核率的影响

目的 研究河流底泥重金属镉污染对鳙鱼血细胞微核率的影响。方法 在含不同浓度Cd^2 底泥环境下饲养鳙鱼，并分别于实验的15、25、35、45、55、65、75和85d，每次每组随机取4尾鱼，取其血细胞涂片、染色．测定其微核细胞率。结果 底泥Cd^2 含量与水体中Cd^2 浓度正相关；随水体中Cd^2 浓度升高，鳙鱼血细胞的微核细胞率也升高，表现出明显的量效关系。结论 河流底泥重金属镉污染对细胞遗传物质有损伤作用。     

Fatty acid composition of tomato leaves as biomarkers of metal-contaminated soils

The aim of this study was to determine whether fatty acid composition of leaves, cotyledons or roots could be used as an indicator of the bioavailability and of the adverse effects of heavy metals on plants. Tomato seedlings were grown on soils obtained by mixing increasing amounts of a highly metal-contaminated soil with an uncontaminated sandy soil, and the fatty acid composition of plant tissues was analyzed. The fatty acid composition of roots and cotyledons of plants grown on contaminated soils was mostly the same as in the control plants. In contrast, significant changes in the fatty acid composition of primary leaves occurred. Our results clearly indicate a relationship between metal accumulation (Cd, Pb, Zn, and Cu) and the fatty acid composition of primary leaves, with the contribution of 18 C atom fatty acids (as 18:3 fatty acid and precursors) being more closely correlated with the availability of heavy metals in soils.     

Heavy Metal Pollution and Ecological Risk Assessment of the Agriculture Soil in Xunyang Mining Area,Shaanxi Province,Northwestern China

Mining is considered to be one of the most significant sources of environmental pollution with regard to heavy metals. Mineral mining causes large quantities of mercury, cadmium, and other elements to be released into the environment and naturally poses a serious threat to environment. This paper will analyze the pollution status of agricultural soil caused by the mining of heavy metals in various mining areas in the Xunyang County in the Shaanxi Province of China, an area in famous for its resource mining. Equally, it will look at the potential ecological risk assessment process that is used to analyze the ecological risks of mining heavy metals in agricultural soil located in the surrounding areas. Based on the soil investigation, As pose a moderate ecological risk on the Au mining area. In addition, the Hg metals pose a significantly high potential ecological risk and Cd metals pose a considerable potential ecological risk on the Hg mining area. In the Pb–Zn mining area, a significantly high potential ecological risk was mainly posed by Cd. These results suggest that many heavy metals pose a high potential ecological risk on the agricultural soil in these three mining areas in the Xunyang County, and may cause elevated heavy metal contents in crops, eventually jeopardizing the health of local residents who consume food grown in polluted soil.     

Cadmium accumulation and biochemical responses in Sparus aurata following sub-lethal Cd exposure

Cadmium (Cd), a heavy metal with limited biological function, is widely distributed in the aquatic environment as a result of natural and anthropogenic activities. The effect of 4 and 11 days exposure of gilthead sea bream Sparus aurata to sub-lethal concentrations of Cd was evaluated as levels of Cd content and Cd-metallothionein (MT) presence in different organs. The possible genotoxic effect was also evaluated in erythrocytes by using the "comet assay", a promising tool for estimating DNA damage at the single-cell level. The results obtained show that in the controls, Cd content was significantly higher in gills compared to in liver, but the treatment of fish with 0.1mg/l Cd induced a stronger accumulation of metal in liver depending on the length of the exposure period. Cd traces were found in plasma, muscle and kidney. Cd forms complexes in the cytosol with MT only in the liver but Cd-MT content significantly increased after 11 days of exposure to the metal, while after 4 days of treatment the protein level was similar to the control. The "comet assay" performed on S. aurata eryhtrocytes isolated from fish treated for 4 and 11 days with 0.1mg/l Cd, showed that there was no DNA damage at both exposure periods.     

Modeling the influence of environmental heterogeneity on heavy metal exposure concentrations for terrestrial vertebrates in river floodplains

To analyze the influence of environmental heterogeneity on heavy metal exposure concentrations for terrestrial vertebrates in river floodplains, a spatially explicit exposure model has been constructed (SpaCE-model: Spatially explicit cumulative exposure model). This model simulates the environmental use of individual organisms by selecting model cells to be foraged in within a multicelled, heterogeneous landscape. Exposure durations and exposure concentrations are calculated for the selected cells, whereby exposure concentrations are dependent on the availability and contaminant concentrations of different diet items in each cell. The model was applied to a selection of 10 terrestrial vertebrate species, including six small mammalian and four top predator species. It was parameterized for cadmium contamination in a 285-ha, embanked floodplain area along the Rhine River in The Netherlands. Simulations of 1,000 individuals for each species resulted in intraspecies variation in exposure concentrations of between 11 and 39%, with the smallest values generally corresponding to the species with the largest home ranges. Comparison of the model results with cadmium concentrations measured in four of the species from the study area showed that the predicted variation accounted for 12 to 16% of the variation in the measurements. This indicates that environmental heterogeneity governs a minor part of the variation in metal exposure concentrations that can actually be observed in river floodplains.     

Effects of heavy metals on production of thiol compounds and antioxidant enzymes in Agaricus bisporus

In a pre-experiment, Agaricus bisporus mycelia grown in PDL medium were found to have a substantial ability to tolerate and accumulate heavy metals. In the study, we investigated changes in the contents of soluble protein and thiol compounds as well as the activities of antioxidant enzymes caused by copper, zinc, lead, and cadmium (nitrate salts) in mycelia of A. bisporus during short-and long-term exposure. Results showed that high-level metal concentrations significantly decrease the contents of soluble protein after long-term exposure, Cu and Zn concentrations significantly increase the thiol compounds levels after long-term exposure, while high-level Cd significantly decrease thiol compounds after long-term exposure. Additionally, SOD activities were significantly increased after long-term exposure to metals, especially to Cd. The CAT activities were enhanced after long-term exposure to low-level Cu and high-level Zn, and enhanced after short-and long-term exposure to high-level Pb. The POD activities were significantly increased after long-term exposure to metals, and increased after short-term exposure to Cd and high-level Pb.     

河南某市河水和污泥中重金属污染状况及评价

目的研究河南省某市郊区河水及其淤泥的重金属污染状况。方法典型性抽样方法选择某市郊区农田灌溉取水河流,利用原子吸收分光光度仪,分别采用石墨炉和火焰法对河水和淤泥中的重金属镉(Cd)、铜(Cu)与铅(Pb)进行了测定。将河水测定结果与《地表水环境质量标准GB3838—2002》及《农田灌溉水质标准GB5084—2005》比较,淤泥样品测定结果与全国土壤背景值进行对比。结果河水样品中铜、镉含量未超过标准,铅含量超标3～6倍。根据单因子污染指数法,河水中Cu、Cd的单因子污染指数均小于0.2,为清洁水平,而Pb则达到6.84,提示河水中Pb污染严重。淤泥中Cu是土壤背景值的4倍多,Cd是土壤背景值的69倍多,Pb是土壤背景值的两倍多,单项污染指数显示淤泥中Pb的污染指数为2.5,属中度污染,淤泥中Cu和Cd的污染指数均大于3,为严重污染,尤以Cd污染突出,其单项污染指数达67.76。河水和淤泥的综合污染指数分别为5.346与84.115,提示二者均属重污染水平,河水的主要污染源于Pb,淤泥的主要污染源于Cd,需要及早处理与控制。     

Dietary Strategies for the Treatment of Cadmium and Lead Toxicity

Cadmium (Cd) and lead (Pb) are toxic heavy metals that cause adverse health effects in humans and animals. Chelation therapy, the conventional treatment for heavy metal toxicity, is reported to have a number of safety and efficacy issues. Recent studies have shown that dietary supplements play important roles in protecting against Cd and Pb toxicity. This paper reviews the evidence for protective effects of essential metals, vitamins, edible plants, phytochemicals, probiotics and other dietary supplements against Cd and Pb toxicity and describes the proposed possible mechanisms. Based on these findings, dietary strategies are recommended for people at risk of Cd and Pb exposure. The application of these strategies is advantageous for both the prevention and alleviation of Cd and Pb toxicity, as such supplements can be added easily and affordably to the daily diet and are expected to have very few side effects compared to the chelation therapy.