Sources and Ecological Risk Assessment of Heavy Metal(loid)s in Agricultural Soils of Huzhou,China

To identify sources of heavy metal(loid) (HM) contamination in agricultural soils of Huzhou, surface soil samples were sampled from 89 different agricultural regions in 2012. Concentrations of heavy metal(loid)s, along with pH, total phosphorus (TP), total nitrogen (TN), and soil organic matter (SOM), were determined. Ecological risk was then assessed using a modified Hakanson ecological risk index, and the sources of contamination were determined using principal component analysis (PCA). Mean concentrations of heavy metal(loid)s were 10.26, 23.21, 83.75, 22.81, 0.25, 61.86, 33.03, and 0.15 mg kg^?1 for As, Cu, Zn, Ni, Cd, Cr, Pb, and Hg, respectively. Cu, Zn, Ni, Cr, Cd, Hg, and Pb were correlated positively with TP and there were obvious positive correlations among Cu, Zn, Ni, Cr, and Cd. Risk index (RI) values varied from 39 to 1246 with a mean value of 137. Enrichment of Pb, Zn, Cu, and especially Cd can be attributed to excessive use of nitrogen and phosphorus fertilizers containing heavy metals, as well to surface irrigation and natural soil formation. While the ecological risk of most agricultural soils in Huzhou is low, it is recommended that the use of phosphate and nitrogen fertilizers be restricted and production technology be improved to reduce the heavy metal(loid) concentrations. Results suggest that the Chinese environmental quality standard for soil should be revised to better address heavy metal(loid) contamination.     

Source apportionment and health risk assessment of heavy metals in agricultural soils in Xinglonggang,Northeastern China

Heavy metals in soil can affect human health through the exposure pathways of oral ingestion, dermal contact, and inhalation. In this study, to assess the health risk of heavy metals in the agricultural area of Xinglonggang, 52 soil samples were collected and tested to obtain the concentrations of As, Cd, Cr, Cu, Ni, Pb, V, and Zn in the soil. The enrichment factor indicated that the heavy metals of the agricultural soils were enriched, but the degree of enrichment was mild for all of the heavy metals. Coefficient analysis and principal component analysis indicated that V, Cr, Ni, and Pb were mainly from natural sources, As was from irrigation, Cu and Cd tended to be from chemical fertilizers and pesticides, and Zn was from mixed sources including irrigation, chemical fertilizers, and pesticides. A human-health risk assessment indicated that the residents in the study area face high risk from carcinogens and low risk from noncarcinogens; As and Cr are the major heavy metals affecting human health. This study provides a reference and a basis for formulating effective measures to prevent and control heavy metal enrichment in agricultural soils.     

Assessment of Heavy Metal Pollution in Urban Agricultural Soils of Jilin City,China

Due to rapid industrialization and urbanization during the last two decades, contamination of urban agricultural soils by heavy metals is on an increase all over China. In this study, fifty soil samples were collected from urban vegetable fields in a chemical industrial area and non chemical industrial area in Jilin City to investigate the heavy metal pollution level. The mean Pb, Cr, Cu, Ni, Zn, and Cd contents (30.84, 65.65, 26.41, 23.07, 135.14, and 0.1434 mg kg^?1 dry weight, respectively) in the urban vegetable soils were higher than their corresponding natural background values. The principal component analysis (PCA) was performed to identify the possible sources of metal contamination in the study area. The results indicated that Cu and Zn were mainly from industrial activities, while Pb and Cd were derived from traffic activities and agricultural activities, and Cr and Ni tended to be from parent material. The distribution of comprehensive pollution index values showed that Pb, Cr, Cu, Ni, Zn, and Cd concentrations in most of the agricultural fields did not exceed the baseline values affecting the safety of agricultural production and human health according to the soil environmental quality standard of China, indicating an insignificant contamination of these metals in Jilin City.     

新疆焉耆盆地辣椒地土壤重金属污染及生态风险预警

从新疆加工辣椒主产地(焉耆盆地)采集105个辣椒地典型土壤样品,测定其中As、Cd、Cr、Cu、Mn、Ni、Pb和Zn等8种重金属元素的含量。采用污染负荷指数(Pollution load index,PLI)、潜在生态风险指数(Potential ecological risk index,RI)和生态风险预警指数(Ecological risk warning index,I_(ER))对辣椒地土壤重金属污染及生态风险进行评价。结果表明:(1)焉耆盆地辣椒地土壤Cd、Cr、Ni、Pb和Zn含量的平均值分别超出新疆灌耕土背景值的1.65、1.40、1.32、3.21、6.42倍。辣椒地土壤Pb和Zn呈现重度污染,Cd、Cr和Ni轻度污染,As、Mn和Cu无污染。(2)土壤PLI平均值为1.40,呈现轻度污染。各重金属元素单项生态风险指数从大到小依次为:Cd、Ni、As、Cu、Pb、Cr、Zn。土壤RI平均值为18.40,属于轻微生态风险态势,IER平均值为-4.78,属于无警态势;博湖县辣椒地污染水平、潜在生态风险程度与生态风险预警等级最高,焉耆县污染水平、潜在生态风险程度与生态风险预警等级最低。(3)辣椒地土壤As、Cd、Pb与Zn主要受到人类活动的影响,Cr、Cu、Mn和Ni主要受到土壤地球化学作用的控制。Cd是焉耆盆地辣椒地生态风险等级最高的重金属元素,研究区农业生产过程中要防范Cd的污染风险。     

Analysis of Spatial Variations and Sources of Heavy Metals in Farmland Soils of Beijing Suburbs

To understand the effect of intense human activities in suburbs on environmental quality, we obtained 758 measurements of the heavy metals in certain farmland soils of the Beijing suburbs. Multivariate statistical analysis and geostatistical analysis were used to conduct a basic analysis of the heavy metal concentrations, the distribution characteristics and the sources of pollution of the farmland soils in these suburbs. The results showed the presence of eight heavy metals in the agricultural soils at levels exceeding the background values for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn. In particular, all the measured Cr concentrations exceeded the background value, while As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn were present at 1.13, 1.68, 1.95, 1.43, 1.63, 0.79, 0.92 and 1.36 times their background values, respectively. The results of correlation, factor and spatial structure analyses showed that Cd, Cu, Pb and Zn were strongly homologous, whereas Cr and Hg showed a degree of heterogeneity. The analysis further indicated that in addition to natural factors, Cd, Cu, Pb and Zn in the soil were mainly associated with distribution from road traffic and land use status. Different agricultural production measures in the various areas were also important factors that affected the spatial distribution of the soil Cr concentration. The major sources of Hg pollution were landfills for industrial waste and urban domestic garbage, while the spatial distribution of As was more likely to be a result of composite pollution. The regional distribution of the heavy metals indicated that except for Cr and Hg, the high heavy metal levels occurred in districts and counties with higher organic matter concentrations, such as the northwestern and southeastern suburbs of Beijing. There was no significant Ni pollution in the agricultural soils of the Beijing suburbs.     

Heavy metal contamination in vegetables grown around peri-urban and urban-industrial clusters in Ghaziabad,India

Heavy metal contamination of agricultural soils resulting from rapid industrialization and urbanization is of great concern because of potential health risk due to dietary intake of contaminated vegetables. The present study aims to evaluate the status of heavy metals contamination of agricultural soils and food crops around an urban-industrial region in India. Transfer factor values of Cu, Cr, Pb, Cd, Zn, and Ni from soil to vegetable was estimated. The mean heavy metal concentrations (mg/kg) in agricultural soils (Cu: 17.8, Cr: 27.3, Pb: 29.8, Cd: 0.43, Zn: 87, Mn: 306.6, Fe: 16984, and Ni: 53.8) were within allowable concentrations for Indian agricultural soil. The concentrations of Pb, Cd, Zn, and Ni in crops/vegetables exceeded the World Health Organization/Food and Agriculture Organization safe limits. Relative orders of transfer of metals from soil to edible parts of the crops/vegetables were Cd > Pb > Ni > Zn > Cu > Cr. The enrichment factors of heavy metals in soil indicated minor to moderately severe enrichment for Pb, Cd, and Ni; minor to moderate enrichment for Zn; no enrichment to minor enrichment for Mn; and no enrichment to moderate enrichment for Cu at different sites. Ecological risk index of soil showed considerable contamination in one of the wastewater irrigated sites.     

Contamination features and health risk of heavy metals in suburban vegetable soils,Yanbian, Northeast China

In recent years, heavy metal contamination in suburban vegetable soils calls for significant concerns due to the rapid urbanization and industrialization. In present study, 110 suburban vegetable soil samples from Yanbian, Northeast China, were collected. Concentration characteristics, pollution level, health risk, and source identification were evaluated by using different quantitative indices. Concentrations of Pb, Cr, Cu, Ni, Zn, Cd, and As in suburban soils were measured. Mean concentrations of Pb, Cr, Cu, Ni, Zn Cd, and As were 34.9 ± 10.5, 73.5 ± 44.4, 29.6 ± 19.4, 23.4 ± 12.0, 88.5 ± 26.7, 0.16 ± 0.16, and 9.24 ± 3.79 mg/kg, which were showed significantly higher than corresponding background values of Jilin province, respectively. The soils were moderately heavy polluted by Cu and Cd based on the results of geo-accumulated index and pollution indices. The pollution load index indicated that almost all of the study area were middle or heavy polluted, especially in Antu County and Helong City. Children in Yanbian may pose non-carcinogenic and carcinogenic risks with the major exposure pathway of ingestion. Principle component analysis results suggested that Pb, Cu, Zn, and Cd were mainly associated with agricultural activities, Ni and Cr were defined as combined source (lithogenic and anthropogenic), and As was tended to be from excessive application of pesticides and industrial activities.     

Impact of Soil Heavy Metal Pollution on Food Safety in China

Food safety is a major concern for the Chinese public. This study collected 465 published papers on heavy metal pollution rates (the ratio of the samples exceeding the Grade II limits for Chinese soils, the Soil Environmental Quality Standard-1995) in farmland soil throughout China. The results showed that Cd had the highest pollution rate of 7.75%, followed by Hg, Cu, Ni and Zn, Pb and Cr had the lowest pollution rates at lower than 1%. The total pollution rate in Chinese farmland soil was 10.18%, mainly from Cd, Hg, Cu, and Ni. The human activities of mining and smelting, industry, irrigation by sewage, urban development, and fertilizer application released certain amounts of heavy metals into soil, which resulted in the farmland soil being polluted. Considering the spatial variations of grain production, about 13.86% of grain production was affected due to the heavy metal pollution in farmland soil. These results many provide valuable information for agricultural soil management and protection in China.     

Spatial variation of soil quality and pollution assessment of heavy metals in cultivated soils of Henan Province,China

Abstract

Eight chemical and physical characteristics and seven biological properties of the soils from five cultivated areas in the Henan Province were quantified. Concentrations of Cu, Cr, Zn and Mn were determined using the flame atomic absorption spectrometry. In addition available phosphorus, chloride, soluble salt and pH were measured. The activities of enzymes were determined by a literature method. The results showed that the concentrations of Mn, Zn and Cr had close relationships with that of available phosphorus, and their concentrations increased with the prolonged application of organic and mineral fertilisers and pesticides-fungicides. The activities of cellulase have a relationship to the concentrations of Zn and Mn at 0.95 levels respectively, Zn and Mn stimulate many enzyme activities. The relationship between protease and available phosphorus was nearly distinctive at 0.95 levels, relating with the use of nitrogen fertiliser in the farmlands. Local organic manures and urea fertilisers did not change the soil characteristics to a great extent. However, the soils showed moderate and moderate-to-strong contamination by Mn and Zn in the study areas. Wastewater and groundwater irrigation, pesticides-fungicides, and fertiliser may be responsible for the elevated concentrations of Zn and Mn in the soil samples.     

Impact of Land-Use Patterns on Chemical Properties of Trace Elements in Soils of Rural,Semi-Urban,and Urban Zones of the Niger Delta,Nigeria

The study of the concentrations of Cr, Zn, Cd, Pb, Ni, and Cu in soils under different land uses in rural, semi-urban, and urban zones in the Niger Delta was carried out with a view to providing information on the effects of the different land uses on the concentrations of trace elements in soils. Our results indicate significant variability in concentrations of these metals in soils under different land uses in rural, semi-urban, and urban zones. The maximum concentrations of metals in the examined soil samples were 707.5 mg.kg^?1, 161.0 mg.kg^?1, 2.6 mg.kg^?1, 59.6 mg.kg^?1, 1061.3 mg.kg^?1, and 189.2 mg.kg^?1 for Cr, Zn, Cd, Pb, Ni, and Cu, respectively. In the rural zone, the cassava processing mill is a potent source of Ni, Cr, Cu, and Zn while agricultural activities are a source of Cd, and automobile emissions and the use of lead oxide batteries constitute the major sources of Pb. In the urban zone, soils around the wood processing mill showed elevated concentrations of Cu, Cr, Zn, and Ni, while soils around automobile mechanic works and motor parks showed elevated levels of Pb. Elevated Cd concentrations were observed in soils under the following land uses: urban motor park, playground, welding and fabrication sheds, and metallic scrap dump. The contamination/pollution index of metals in the soil follows the order: Ni > Cd > Cr > Zn > Cu > Pb. The multiple pollution index of metals at different sites were greater than 1, indicating that these soils fit into “slight pollution” to “excessive pollution” ranges with significant contributions from Cr, Zn, Cd, Ni, and Cu.     

Trace Element Composition of Selected Fertilizers Used in Chile: Phosphorus Fertilizers as a Source of Long-Term Soil Contamination

Anthropogenic activities like agriculture have resulted in increased concentrations of some trace elements of toxicological and environmental concern in soils. Application of fertilizers has been one of the major inputs of these contaminants to agricultural soils in developing countries. Twenty-two fertilizers, including straight nitrogen (N), phosphorus (P), potassium (K), and NK fertilizers and micronutrient sources, were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn). As expected, the trace element content of fertilizers was highly variable and related to the origin of the material. Phosphorus fertilizers, especially triple superphosphate, presented the highest As, Cd, Cu, Cr, Ni, V, and Zn concentrations. In some of these fertilizers, the Cr, V, and Zn contents reached values greater than 3475 mg kg^?1 of P, and the Cd content (up to 288 mg kg^?1 of P) was several times higher than the regulatory limits of different countries. Some micronutrient sources presented the highest concentrations of Mn and Pb. In the cases of N, K, and NK fertilizers, the trace element concentration was very low, sometimes below the detection limits. In some agricultural systems the input of trace elements such as As and Cd to the soil through P fertilizers application may be higher than the outputs through plant uptake and leaching; therefore the long-term use of these fertilizers may cause the trace element concentration to increase in the plow layer of agricultural soils.     

Copper and zinc fractions affecting microorganisms in long-term sludge-amended soils

The influences of Zn and Cu on soil enzyme activities (acid phosphatase, alkaline phosphatase, arylsulfatase, cellulase, dehydrogenase, protease (z-FLase), urease, beta-D-glucosidase and beta-D-fructofuranosidase (invertase)) and microbial biomass carbon were investigated in agricultural soils amended with municipal sewage sludge or compost since 1978. The trace metals in the soils were fractionated using a sequential extraction method. Long-term application of the sewage sludge and composts caused accumulations of Cu and Zn in the soils, ranging from 140 to 144 and from 216 to 292 mg kg(-1), respectively. The percentage of Cu was highest in the NaOH- and HNO3-extractable fractions (44-51% and 38-46%, respectively), while the percentage of Zn was highest in the HNO3- and EDTA-extractable fractions (65-83% and 11-32%, respectively). Although the percentage of the bioavailable fractions (sum of KNO3 + H2O-, NaOH-, and EDTA-extractable amounts) of Cu (53-64%) was higher than that of Zn (15-37%), the percentage of the most labile fractions (KNO3 + H2O) of Zn (2.1-5.9%) was larger than that of Cu (1.1-2.4%). The size of the microbial biomass carbon increased with the application of sewage sludge or compost. For some enzymes, however, the ratio of the enzyme activity to microbial biomass was lower in the soils amended with sewage sludge or compost than that in the control soil. The soil enzyme activities were more adversely affected by Zn than by Cu. From a multiple regression analysis, it was found that dehydrogenase, urease, and beta-D-glucosidase activities were reduced by the KNO3 + H2O-extractable fraction of Zn in the soils. These microbial activities seem to be sensitive to Zn stress, indicating the possibility that they might be useful bioindicators for evaluation of the toxic effects of Zn on microorganisms in the soils.     

冶炼厂污灌区土壤铜和锌污染与土壤酶活性

通过对冶炼厂污灌区土壤和水稻中Cu、Zn含量分析以及土壤酶活性的测定,研究了距冶炼厂不同距离土壤Cu、Zn含量状况、水稻对它们的吸收和分配以及土壤酶活性的变化.结果表明,冶炼厂造成了周围农田土壤的Cu、Zn污染,其中Cu污染较严重,距离冶炼厂100 m处的全量和提取态Cu分别为182.4和81.91 mg·kg^-1,是对照的10.3和3倍.污灌区水稻各器官Cu、Zn的分布规律是,Cu:根＞茎叶＞米;Zn:茎叶＞根＞米.Zn在水稻体内的移动能力大于Cu,Cu主要累积在水稻根部,根可作为一种屏障阻碍Cu向地上部分迁移,使地上部分免受其害.水稻茎叶Cu含量和土壤中Cu的浓度密切相关.对蔗糖酶、过氧化氢酶和脲酶活性测定表明,脲酶活性变化最显著,其活性与土壤中Cu的浓度显著相关,建议用脲酶活性作为污灌区Cu污染指标.     

南京城市土壤重金属含量及其影响因素

研究了南京城市土壤重金属含量、来源及其与土壤性质的关系。结果表明,南京城市土壤中,Fe、Ni、Co、V污染不明显,但受到了不同程度的Mn、Cr、Cu、Zn、Pb污染,其中：Pb污染非常严重;重金属在土壤剖面分布没有规律性;Fe、Ni、Co、V元素主要来源于原土壤物质,Cu、Zn、Pb、Cr元素主要来源于人为输入,Mn可能在不同的土壤中来源不同;Fe、Cr、Ni、Co、V元素含量之间均呈极显著正相关,Cu、Zn、Pb、Cr元素含量之间均呈极显著正相关。Fe、Co、V、Ni含量与粘粒含量、CEC呈极显著正相关;Cu、Zn、Pb含量与粘粒含量呈极显著负相关;Cu、Zn、Pb、Cr含量与有机碳呈极显著正相关,Pb含量与pH呈极显著正相关。     

Relationships among site characteristics,taxonomical structure and functional trait distribution of arthropods in forest,urban and agricultural soils of Southern Italy

Urbanization and agriculture cause alterations in soil biodiversity. As arthropods quickly respond to soil changes, they have been recognized as good indicators of soil quality. This study aimed to evaluate if (1) soil physico-chemical properties act as environmental filters of the functional trait distribution of soil arthropod community; (2) the abundance of certain functional traits is linked to different land uses; (3) the taxonomical and functional approaches provide complementary information about the evaluation of biological soil quality. The study was performed at forest, agricultural and urban sites in downtown and surroundings of Naples. The soils were characterized for texture, pH, organic matter content, water content, total Cd, Cr, Cu, Ni, Pb and Zn concentrations. The forest soils showed the highest organic matter and water contents, and the lowest metal concentrations; the agricultural soils showed the lowest organic matter and water contents and high Cd and Cu concentrations, whereas the urban soils showed high Pb and Zn concentrations. The forest soils showed the highest arthropod density, taxa richness and diversity. The distribution of the functional traits in the arthropod communities of the different land uses highlighted similarity only for the preference to occupy soil and for the percentage contribution of detritivores. The abundance of arthropods living above litter and omnivores were positively correlated to Pb and Zn concentrations, whereas predators were positively correlated to Cu concentrations. The findings suggest that the arthropod identification at order level could be enough to detect differences in functional traits among forest, urban, and agricultural soils.     

贵州兴仁煤矿区农田土壤重金属化学形态及风险评估

为了解煤矿区周边农田土壤重金属污染状况,采集了贵州省兴仁县某典型煤矿区农田土壤样品64份,测定了土样中重金属(As、Cr、Pb、Zn、Cd、Hg、Cu、Ni)总量及各形态含量,采用单因子指数法、潜在生态风险指数法(Hkanson法)和风险评估编码法(RAC)对研究区主要土壤利用类型(水稻土、薏米地、植烟土和菜园土)中重金属进行潜在生态风险评估和环境风险评价.结果表明： 不同利用类型土壤中重金属含量除Zn外,其他元素均明显超过贵州省背景值.单因子指数法评价结果表明,As、Pb、Hg和Cu污染较为严重,均属重度污染.形态分析表明,土壤中重金属形态构成差异明显,酸可提取态As、酸可提取态Cd所占比例较高;Cr、Zn、Cu、Ni主要以残渣态为主;Pb主要以可还原态和残渣态为主;而Hg的酸可提取态、可还原态、可氧化态均占有相当比例,三者之和大于55%.重金属可利用度大小顺序为:As(63.6%)>Hg(57.3%)>Cd(56.4%)>Pb(52.5%)>Cu(45.7%)>Zn(32.8%)>Ni(26.2%)>Cr(13.2%).潜在生态风险指数表明,各类型土壤潜在生态风险(RI)〖JP2〗为:菜园土(505.19)>薏米地(486.06)>植烟土(475.33)>水稻土(446.86),均处于较高风险.风险评估编码法结果显示,As在水稻土、薏米地及植烟土中均处于高风险,在菜园土中处于中等风险;Cd、Hg均处于中等风险,Cr、Pb、Zn、Cu和Ni均处于低风险.因此,对该区域农田土壤进行管控时应重点考虑As、Cd和Hg污染.     

Concentrations and chemical forms of heavy metals in agricultural soil near the world’s largest and oldest tungsten mine located in China

Abstract

Tungsten (W) mining has taken place in Ganzhou in China for about 100 years. Such long-term W mining may release large amount of metals to soils and waters around these mines. Twenty soil samples were taken from the area around the W mines and 10 soil samples from an area much farther away. These soil samples were analysed for physicochemical properties, heavy metal content and their chemical forms. Results show that long-term W mining significantly increased both total and labile contents of Cd, Cu, Pb and Zn, but did not, or only slightly, increased the total content of Co, Cr and Ni in the soil near the mine. Average enrichment factor (EF) in the agricultural soils was 4.0, 2.4, 2.2, and 2.0 for Cd, Cu, Pb and Zn, respectively. The labile fraction was dominated by the carbonate-bound fraction for Cd (54.5%) and organic matter-bound fraction for Cu (37.9%), while the major labile fractions for Pb and Zn were associated with carbonates (30.2% and 6.4%), oxides (17.9% and 10.6%) and organic matter (9.2% and 18.8%). Consequently, there is a need to be cautious about Cd in the soils contaminated by W mining.     

Heavy metal contamination in surface soils of the industrial district of Wuhan,China

The Qingshan district of Wuhan City is a typical Chinese industrial area. An increase in heavy metal pollution in the region's soil, due to industrialization and urbanization, has become a serious environmental problem. Surface soil samples from 155 sites were collected and analyzed. The median concentrations of cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) in soil were 2.3, 46.2, 24.3, 28.2, and 86.8 mg/kg, respectively. Principal component analysis coupled with hierarchical cluster analysis showed that (1) in residential and industrial areas, Pb, Cu, and Zn concentrations were mainly affected by industrial emissions and traffic emissions, whereas in agricultural areas Cu and Zn were less affected by industrial emission and traffic emission, whereas Pb was affected by agricultural activities; and (2) Cd originated from a combination of sources, including industrial activities, traffic emission, and hypergene geochemical characteristics. The integrated pollution index varied from 1.1 to 16.6 with a mean of 3.9, and 70.6% of the area is extremely contaminated, 28.1% is heavily contaminated, and the remainder is moderately contaminated.     

不同土地利用方式对城市土壤质量的影响

通过对兰州市西固区种土地利用类型(工业园区、道路两侧、农业、居民区和公园)320个土壤样品的测试,研究了不同土地利用方式对城市土壤理化性状和Pb、Zn、Cd、Cu、Hg元素积累的影响.在种类型土壤中,工业园区土壤的pH值最低而电导率最高,道路两侧土壤有机碳含量显著高于居民区、公园和农业土壤;Pb、Zn、Cu、Cd和Hg的含量在种类型土壤中存在显著差异,并明显高于兰州市土壤背景值;计算得到的工业园区、道路两侧、农业、居民区和公园土壤的内梅罗综合污染指数分别为4.9、3.7、4.0、2.4和2.2.结果表明,不同土地利用方式对城市土壤质量的影响不同,工业活动的影响最大,交通污染次之,再依次为农业活动及居民生活.     

Bioavailability of Metals in Soil and Health Risk Assessment for Populations Near an Indian Chromite Mine Area

Soils contaminated with toxic metals may be environmental hazards and sources of exposure to human population. Soils in mining areas are among the most heavily contaminated by metals from the mining activity. This study was focused on metals of interest in bioavailability studies using single and sequential extraction methods. Results of geochemical fractionation suggest that changes in soil characteristics may enhance the mobilization of Cu, Cr, Zn, and Al. The observed metals’ availability pattern was Cr > Cu > Zn > Al. However, the pattern of total contents of metals in soils was Al > Cr > Zn > Cu. Risks to human adults and children from selected metals through soil ingestion was assessed in terms of incremental lifetime average daily dose (LADD), hazard quotient (HQ), and hazard index (HI). The estimated LADDs and HI were within acceptable reference doses and less than 1, respectively, indicating low risk to human populations from the studied metals through soil ingestion in the studied mine area. The generated data may be useful in remediation of contaminated soils with metals.