南方某典型矿冶污染场地健康风险评价及修复建议

矿区及周边土壤重金属污染不容忽视,砷、镉和铅等对周边人群造成较高的健康风险隐患。以南方红壤区某铅锌冶炼矿区污染场地为研究对象,开展危害识别、暴露评估、毒性评估及风险表征,并讨论场地修复目标值与修复技术。结果表明：土壤受到重金属复合污染,关注污染物为四类重金属,包括铅、砷、镉和锌,集中于表层土壤（0~0.6 m）,并呈现空间分布规律性;场地未来用地类型为工业用地,对比污染物（不包括铅）各层（第1层0~0.3 m、第2层0.3~0.6 m、第3层0.6~1.0 m）风险表征值,污染物（砷、镉）存在致癌风险与非致癌危害,研究区重金属污染累积风险水平不可接受;分析风险控制值及国内外相关标准限值等,初步建议砷、镉和铅的修复目标值分别为13.41、21.50和600 mg·kg-1;同时,针对场地污染现状及健康风险,建议源控制与修复技术并用,并与当地工业园区建设统筹开展。     

Heavy metal pollution in vegetables grown in the vicinity of a multi-metal mining area in Gejiu,China: total concentrations,speciation analysis,and health risk

A field survey was conducted to investigate the present situation and health risk of arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in soils and vegetables in a multi-metal mining area, Gejiu, China. Furthermore, three vegetables (water spinach, potato, and summer squash) containing high metal concentrations were selected to further analyze metal speciation. The results showed that the average concentrations of five metals in soil exceeded the limiting values, and their bioavailable concentrations were significantly positively correlated to the total ones. Heavy metals in the edible parts of vegetables also exceeded the corresponding standards. The leaves of pakchoi, peppermint, and coriander had a strong metal-accumulative ability and they were not suitable for planting. Except the residue forms, the main forms of metals in the edible parts of three selected vegetables were ethanol-, NaCl-, and HAc-extractable fractions for As, Pb, and Cd, respectively; however, Cu was mainly presented as NaCl-extractable and Zn as HAc-extractable fractions. A high proportion of ethanol-extractable As showed that As bioactivity and toxic effects were the highest. Although the total and bioavailable Cd were high in soil, its speciation in vegetables was mainly presented as HAc-extractable fraction, which has a relatively low bioactivity. Lead and arsenic were imposing a serious threat on the local residents via vegetable consumption.     

Trace metal uptake by tropical vegetables grown on soil amended with urban sewage sludge

Trace metal uptake was measured for tropical and temperate leafy vegetables grown on soil from an urban sewage disposal farm in the UK. Twenty-four leafy vegetables from East Africa and the UK were assessed and the five vegetable types that showed the greatest Cd concentrations were grown on eight soils differing in the severity of contamination, pH and other physico-chemical properties. The range of Cd concentrations in the edible shoots was greater for tropical vegetables than for temperate types. Metal uptake was modelled as a function of (i) total soil metal concentration, (ii) CaCl₂-soluble metal, (iii) soil solution concentration and (iv) the activity of metal ions in soil pore water. Tropical vegetables were not satisfactorily modelled as a single generic ‘green vegetable’, suggesting that more sophisticated approaches to risk assessment may be required to assess hazard from peri-urban agriculture in developing countries.     

Health risk assessment of heavy metals in soil-plant system amended with biogas slurry in Taihu basin,China

Biogas slurry is a product of anaerobic digestion of manure that has been widely used as a soil fertilizer. Although the use for soil fertilizer is a cost-effective solution, it has been found that repeated use of biogas slurry that contains high heavy metal contents can cause pollution to the soil-plant system and risk to human health. The objective of this study was to investigate effects of biogas slurry on the soil-plant system and the human health. We analyzed the heavy metal concentrations (including As, Pb, Cu, Zn, Cr and Cd) in 106 soil samples and 58 plant samples in a farmland amended with biogas slurry in Taihu basin, China. Based on the test results, we assessed the potential human health risk when biogas slurry containing heavy metals was used as a soil fertilizer. The test results indicated that the Cd and Pb concentrations in soils exceeded the contamination limits and Cd exhibited the highest soil-to-root migration potential. Among the 11 plants analyzed, Kalimeris indica had the highest heavy metal absorption capacity. The leafy vegetables showed higher uptake of heavy metals than non-leafy vegetables. The non-carcinogenic risks mainly resulted from As, Pb, Cd, Cu and Zn through plant ingestion exposure. The integrated carcinogenic risks were associated with Cr, As and Cd in which Cr showed the highest risk while Cd showed the lowest risk. Among all the heavy metals analyzed, As and Cd appeared to have a lifetime health threat, which thus should be attenuated during production of biogas slurry to mitigate the heavy metal contamination.     

Cytotoxic and genotoxic effects of metal(oid)s bioactivated in rocket leaves (Eruca vesicaria subsp. sativa Miller)

Rocket is an important source of essential elements. However, it may also accumulate toxic elements such as metal(oids). The objectives of the present work were (i) to study the uptake of arsenic, lead, cadmium and zinc in rocket grown in contaminated soils, (ii) to establish the genotoxic and cytotoxic activities of this vegetable material, and (iii) to study the modulator role of the glucosinolate and metal contents in the genotoxic/cytotoxic activities. Lead, cadmium and zinc leaf concentrations in our study were over the concentrations allowed by the statutory limit set for metal(oid) contents in vegetables. The accessions were non genotoxic at the different concentrations studied, although one of the accessions showed the highest mutation rates doubling those of negative control. The cytotoxicity assays with HL60 human leukaemia cells showed that the tumouricide activities of rocket leaves decreased with the increasing of metal(oid) concentrations and also with the decreasing of glucosinolate concentrations in their tissues. An interaction between metal(oid)s and glucosinolate degradation products contained in rocket leaves is suggested as the main modulator agents of the biological activity of the plants grown in metal-contaminated soils.     

Palygorskite as a feasible amendment to stabilize heavy metal polluted soils

The sorption behaviour of palygorskite has been studied with respect to lead, copper, zinc and cadmium in order to consider its application to remediate soils polluted with these metals. The Langmuir model was found to describe well the sorption processes offering maximum sorption values of 37.2 mg/g for lead, 17.4 mg/g for copper, 7.11 mg/g for zinc and 5.83 mg/g for cadmium at pH 5-6. In addition the effect of palygorskite amendment in a highly polluted mining soil has been studied by means batch extractions and leaching column studies. The soluble metal concentrations as well as the readily-extractable metal concentrations were substantially decreased at any concentration of palygorskite applied to soil (1, 2, 4%), although the highest decrease is obtained at the 4% dose. The column studies also showed a high reduction in the metal leaching (50% for lead, 59% for copper, 52% for zinc and 66% for cadmium) when a palygorskite dose of 4% was applied.     

Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. I. From the tree crown to leaf cell level

In order to achieve efficient phytoextraction of heavy metals using trees, the metal allocation to aboveground tissues needs to be characterised. In his study, the distribution of heavy metals, macro- and micronutrients and the metal micro-localisation as a function of the leaf position and heavy metal treatment were analysed in poplars grown on soil with mixed metal contamination. Zinc was the most abundant contaminant in both soil and foliage and, together with cadmium, was preferentially accumulated in older foliage whereas excess copper and lead were not translocated. Changes in other element concentrations indicated an acceleration in aging as a consequence of the metal treatment. Excess zinc was irregularly accumulated inside leaf tissues, tended to saturate the veins and was more frequently stored in cell symplast than apoplast. Storage compartments including metabolically safe and sensitive subcellular sites resulted in sizable metal accumulation as well as stress reactions.     

Metal accumulation in arthropods near a lead/zinc smelter in Arnoldstein, Austria. I

This study reports on accumulation of lead, cadmium, copper and zinc in soil, plants and arthropod species in the vicinity of a closed-down lead/zinc smelter with a long history of pollution in Arnoldstein, Austria. Significant site-dependent metal accumulations were measured in most species, increasing in line with site contamination. Within a site, clear species-specific differences were found, even between closely related species. Within some species, developmental-, sex- and/or seasonal-specificities occurred, reflecting individual metal budgeting capabilities. Evidence for copper regulatory mechanisms appeared to be established in most cases, whereas lead, the main pollutant of the region, became heavily accumulated in some organisms. Higher levels of lead than previously reported in field surveys were detected in Carabidae and Caelifera at the most polluted site. It is recommended to take ecological and physiological parameters of species into consideration in interpreting field data on arthropod metal accumulation.     

Investigation of heavy metal accumulation in Polygonum thunbergii for phytoextraction

In this study, cadmium (II), lead (II), copper (II) and zinc (II) were determined in Polygonum thunbergii and soil from the Mankyung River watershed, Korea. Soil samples contained detectable lead (<17.5 g g(-1)), copper (<8.4 g g(-1)) and zinc (<24.5 g g(-1)), whereas cadmium was undetectable. Whole plants of P. thunbergii contained detectable lead (<320.8 g g(-1)), copper (<863.2 g g(-1)) and zinc (<2427.3 g g(-1)), whereas cadmium was detectable only in the stem (<7.4 g g(-1)) and root (<10.1 g g(-1)). Whole plant concentrations were very different for each metal, particularly in the case of zinc. The mean content of heavy metal in the whole plants increased in the order of cadmium (8.5 g g(-1))相似文献   

Mayfly larvae (Baetis rhodani and B. vernus) as biomonitors of trace metal pollution in streams of a catchment draining a zinc and lead mining area of Upper Silesia,Poland

Larvae of two Baetis species were used to investigate spatial and temporal variability in the bioavailabilities of cadmium, copper, lead, zinc and iron in the river Biala Przemsza and its tributaries draining an area of lead and zinc mining in Upper Silesia, Poland. Accumulated metal concentrations were measured in April, May, August and November 2000. Both species indicated significant local geographical variability in availabilities of zinc, iron, lead and cadmium, but not copper. Accumulated concentrations of lead, zinc and cadmium confirmed the high general contamination of the Biala Przemsza system by these three trace metals. Larvae showed little seasonal variation in concentrations of cadmium, copper, lead and iron. Accumulated zinc concentrations were low in Baetis rhodani in August, perhaps as a result of insufficient time for high concentrations to accumulate since hatching of the larvae. Samples collected in August most nearly matched criteria of the greatest availability of larvae for collection and their size homogeneity, minimising the possibilities of any effect of differential larval size and/or age on accumulated metal concentrations. Mayfly larvae are members of a suite of potential stream biomonitors in Central Europe, which together can provide information on the different sources of bioavailable trace metals present in aquatic ecosystems.     

Accumulation of heavy metals and antioxidant responses in Vicia faba plants grown on monometallic contaminated soil

The purpose of this study was to explore the effects of soil contamination by selected metals (cadmium, copper, nickel, lead or zinc) on the antioxidant response of Vicia faba plants. The levels of the antioxidants: glutathione, proline, non-protein thiols, as well as guaiacol peroxidase and catalase activities were measured in the upperparts of plants. Additionally, the potential bioavailability of metals in the soil and their concentrations in V. faba plants were compared. Treatment with metal caused the problem of an elevation in its bioavailability in soil and its concentration in leaves and stems. The most serious problems seemed to be metal elevations in soil, especially Zn and Ni as well as in the aerial parts of V. faba plants. The antioxidant responses appeared to be metal specific. The elevation of guaiacol peroxidase activity in leaves and stems as well as the proline in leaves was the only more general reaction to metal exposure. Upon analysis of the effects of soil metal contamination on V. faba plants, we recommend the use of some measurements such as guaiacol peroxidase activity and proline level as useful tools in biological monitoring.     

Influence of initial pH on bioleaching of heavy metals from contaminated soil employing indigenous Acidithiobacillus thiooxidans

Bioleaching of heavy metals from contaminated soil was carried out employing indigenous sulfur oxidizing bacterium Acidithiobacillus thiooxidans. Experiments were carried out to assess the influence of initial pH of the system on bioleaching of chromium, zinc, copper, lead and cadmium from metal contaminated soil. pH at the end of four weeks of bioleaching at different initial pH of 3-7 was between 0.9 and 1.3, ORP between 567 and 617mV and sulfate production was in the range of 6090-8418mgl(-1). Chromium, zinc, copper, lead and cadmium solubilization ranged from "59% to 98%" at different initial pH. A. thiooxidans was not affected by the increasing pH of the bioleaching system towards neutral and it was able to utilize elemental sulfur. The results of the present study are encouraging to develop the bioleaching process for decontamination of heavy metal contaminated soil.     

Effect of ferrous sulfate on parathion degradation in flooded soil.

In an isotope study, the effect of ferrous sulfate on the degradation of parathion was studied under flooded soil conditions. The addition of ferrous sulfate to flooded soil led to more rapid and extensive degradation of parathion with the formation of additional degradation products in ferrous sulfate-amended soil. This effect was not pronounced when ferrous sulfate was added to non-flooded soil or to flooded autoclaved soil. Sulfate, rather than Fe2+, was implicated in the extensive degradation of parathion.     

Heavy metals in soils along unpaved roads in south west Cameroon: Contamination levels and health risks

Soils enriched with heavy metals from vehicular emission present a significant exposure route of heavy metals to individuals using unpaved roads. This study assessed the extent of Cd, Cr, Co, Cu, Ni, Pb and Zn contamination of soils along unpaved roads in Cameroon, and the health risks presented by incidental ingestion and dermal contact with the soils using metal contamination factor (CF) pollution load index, hazard quotients (HQ) and chronic hazard index (CHI). CF values obtained (0.9–12.2) indicate moderate to high contamination levels. HQ values for Cr, Cd and Pb exceeded the reference doses. Moderate health hazard exists for road users in the areas with intense anthropogenic activities and high average daily traffic (ADT) volume according to CHI values (1–4) obtained. The economy and quality of life in cities with unpaved roads could be threatened by health challenges resulting from long-term exposure to heavy metal derived from high ADT volumes.     

Assessment of soil lead exposure in children in Shenyang, China

Soil lead pollution is serious in Shenyang, China. The paper brings together the soil work, the bioaccessibility, and the blood lead data to assess the soil lead exposure in children in Shenyang, China. Approximately 15.25% of the samples were above China Environment Protection Agency guideline concentration for soil Pb to protect human from health risk (350 mgkg(-1)). Pb concentrations varied among use scenarios. The main lead contamination sources are industry emission and automobile exhaust. Bioaccessibility also varied among use scenarios. Children, who ingested soil from industrial area, public parks, kindergarten playground, and commercial area, are more susceptible to soil lead toxicity. The industrial area soil samples presented higher bioaccessibility compared to the other use scenario soil samples contaminated by automobile exhaust. The result also suggested a most significant linear relationship between the level of Pb contamination and the amount of Pb mobilized from soil into ingestion juice. Soil pH seemed to have insignificant influence on bioaccessibility in the present study. Bioaccessibility was mainly controlled by other factors that are not investigated in this study. A linear relationship between children blood lead and soil intestinal bioaccessibility was present in the study. Children who are 4-5 years old are more likely to demonstrate the significant relationship between soil lead bioaccessibility and blood lead as their behaviors place them at greatest risk of soil lead toxicity, and their blood lead levels are more likely to represent recent exposure.     

Persistence of alpha and beta isomers of endosulphan and endosulphan sulphate in diverse soils of India as influenced by flooding

Laboratory studies were undertaken to evaluate the persistence of alpha-endosulphan, beta-endosulphan and endosulphan sulphate in four diverse soils under non-flooded and flooded conditions. Significant variations were observed in the extent of persistence of the three chemicals in different non-flooded soils with maximum persistence observed in Alfisol and the least in Mollisol having near neutral pH and higher organic matter. Degradation was more in all the flooded soils than in the non-flooded counterpart but in Vertisol under flooded and non-flooded conditions, the rate of degradation of endosulphan sulphate was found to be nearly same.     

Recombinant luminescent bacterial sensors for the measurement of bioavailability of cadmium and lead in soils polluted by metal smelters

Environmental hazard of heavy metals in soils depends to a large extent on their bioavailability. The approach used in this study enables the determination of bioavailable metals in solid-phase samples. Two recombinant bacterial sensors, one responding specifically to cadmium and the other to lead and cadmium by increase of luminescence (firefly luciferase was used as a reporter) were used to determine the bioavailability of these metals in soil-water suspensions (a contact assay) and respective particle-free extracts. Fifty agricultural soils sampled near zinc and lead smelters in the Northern France containing up to (mg/kg) 20.1 of Cd, 1050 of Pb and 1390 of Zn were analysed. As the soil matrix interferes with the assay, recombinant luminescent control bacteria lacking the metal recognizing protein and corresponding promoter (thus, being not metal-inducible) but otherwise comparable to the sensor bacteria (the same host bacterium and plasmid encoding luciferase) were used in parallel to take into account the possible quenching and/or stimulating effects of the sample on the luminescence of the sensor bacteria. Both, chemical and sensor analysis showed that only microg/l levels of metals were extracted from the soil into the water phase (0.1% of the total Cd, 0.07% of Pb and 0.5% of Zn). However, 115-fold more Cd and 40-fold more Pb proved bioavailable if the sensor bacteria were incubated in soil suspensions (i.e., in the contact assay). The bioavailability of metals in different soils varied (depending probably on soil type) ranging from 0.5% to 56% for cadmium and from 0.2% to 8.6% for lead.     

福州市主栽蔬菜品种对砷的积累及健康风险

为阐明福州市主要蔬菜基地种植的蔬菜中砷积累特征与食用风险水平,对研究区域内蔬菜和对应土壤中砷含量进行了分析检测,采用Monte-Carlo 模型法对蔬菜中砷引起的健康风险进行了评价,并探讨了蔬菜和土壤砷含量之间的相关性及不同品种、不同类别蔬菜之间积累砷的差异。结果表明：研究区内菜地土壤没有明显的砷超标,砷含量均未超出国家土壤二级标准（30 mg·kg-1）;研究区内蔬菜安全状态很好,不存在明显的健康风险;蔬菜中砷与其对应土壤中砷之间无显著相关性;不同类别的蔬菜之间对于砷的累积存在差异性,蔬菜中砷的富集系数顺序为叶菜类 > 根茎类 > 瓜果类,其中茼蒿的富集系数最大,豌豆和辣椒的最小。     

Food crop accumulation and bioavailability assessment for antimony (Sb) compared with arsenic (As) in contaminated soils

Field samples and a 9-week glasshouse growth trial were used to investigate the accumulation of mining derived arsenic (As) and antimony (Sb) in vegetable crops growing on the Macleay River Floodplain in Northern New South Wales, Australia. The soils were also extracted using EDTA to assess the potential for this extractant to be used as a predictor of As and Sb uptake in vegetables, and a simplified bioaccessibility extraction test (SBET) to understand potential for uptake in the human gut with soil ingestion. Metalloids were not detected in any field vegetables sampled. Antimony was not detected in the growth trial vegetable crops over the 9-week greenhouse trial. Arsenic accumulation in edible vegetable parts was <10 % total soil-borne As with concentrations less than the current Australian maximum residue concentration for cereals. The results indicate that risk of exposure through short-term vegetable crops is low. The data also demonstrate that uptake pathways for Sb and As in the vegetables were different with uptake strongly impacted by soil properties. A fraction of soil-borne metalloid was soluble in the different soils resulting in Sb soil solution concentration (10.75?±?0.52 μg L^–1) that could present concern for contamination of water resources. EDTA proved a poor predictor of As and Sb phytoavailability. Oral bioaccessibility, as measured by SBET, was <7 % for total As and <3 % total Sb which is important to consider when estimating the real risk from soil borne As and Sb in the floodplain environment.     

Effects of pH on the toxicity of cadmium, copper, lead and zinc to Folsomia candida Willem, 1902 (Collembola) in a standard laboratory test system

EC₅₀s for cadmium, copper, lead and zinc were determined for juvenile production of Folsomia candida at pH6.0, 5.0 and 4.5 in a standard laboratory test system. In contrast to most previous studies where metal toxicity was increased at low pHs, in our experiments there was no clear relationship between soil acidity and EC_{50-reproduction} in this species. The EC_{50-reproduction} values (μg g⁻¹) for cadmium and zinc were similar at all three pHs (pH6.0: Cd 590, Zn 900; pH5.0: Cd 780, Zn 600; pH4.5: Cd 480, Zn 590). In contaminated field sites adjacent to primary zinc smelters, zinc is invariably present in soils at concentrations of at least 50 times that of cadmium Thus deleterious effects of mixtures of these metals on populations of Collembola in such sites can be attributed to zinc rather than cadmium.