Heavy Metal Phytotoxicity to Radish (Raphanus sativus L.) in a Digested Sludge-amended Gangetic Alluvium

A limiting factor in land application of sewage sludge is the resultant heavy metal accumulation in soils followed by biomagnification in the food chain, posing a potential hazard to animal and human health. In view of this fact, pot experiments were conducted to evaluate the effect of digested sludge application to soil on phytotoxicity of heavy metals such as Cd, Cr, Ni, and Pb to radish (Raphanus sativus L.) plants. Increasing sludge levels resulted in increased levels of DTPA-extractable heavy metals in the soil. Cadmium was the dominant metal extracted by DTPA followed by Ni, Pb, and Cr. The extractability of metals by DTPA tended to decrease from the first to the second crop. Dry matter yield of radish increased significantly as a function of increasing sludge treatments. Soil application of sludge raised the concentration of one or more heavy metals in plants. Shoots contained higher concentrations of Cd, Cr, and Ni than the roots of radish plants. Shoot concentrations of Cd, Cr, Ni, and Pb were within the tolerance levels of this crop at all rates of sludge application. Shoot as well as root concentration of Cd was above 0.5 mg kg^?1, considered toxic for human and animal consumption. The levels of DTPA-extractable Cd and Ni were less correlated while those of Cr and Pb were more correlated with their respective shoot and root contents. The results emphasize that accumulation of potentially toxic heavy metals in soil and their build-up in vegetable crops should not be ignored when sludge is applied as an amendment to land.     

设施菜地重金属的剖面分布特征

以山东省寿光市种植1～12年的蔬菜大棚及相邻的小麦地为对象,研究了设施菜地中As、Cd、Cu、Zn、Cr、Ni 6种重金属在土壤剖面中的分布特征.结果表明：在0～150 cm土层内,随着土层深度的增加,设施菜地与小麦地中6种重金属含量均呈下降趋势;与小麦地相比,相同土层设施菜地中6种重金属的含量均明显较高,设施菜地0～20 cm土层中As、Cd、Cu、Zn、Cr、Ni的含量分别比小麦地相同土层高出35.0%、146.2%、65.6%、36.4%、21.5%和14.0%,120～150 cm土层分别高出10.6%、.5%、19.4%、20.2%、15.2%和9.3%,20～120 cm各土层中的含量亦高于小麦地.设施菜地0～20 cm土层中,Cd、Cu、Zn含量与种植年限呈显著正相关,随着种植年限的增加,其累积速率分别为0.027、1.153和2.830 mg·kg^-1·a^-1;设施菜地中6种重金属的含量与土壤有机碳、全氮含量呈正相关,除Ni和As外的4种重金属含量亦与土壤全磷含量呈极显著相关,有机肥等的施用可能在一定程度上导致设施菜地中重金属的累积.     

粉煤灰滤泥混合物对土壤性质、萝卜产量与品质的影响

粉煤灰和滤泥以1：1（w/w）比例混合并添加少量化肥配制成混合物,通过盆栽试验研究该混合物农用对土壤生物化学性质、萝卜产量和品质的影响以及重金属在土壤和萝卜中的富集状况。结果表明,该混合物中Dd、Pb、Cr、As和Hg含量均明显低于国家农用粉煤灰中污染物控制标准;施用一定数量的该混合物未见导致重金属在土壤和萝卜中的明显富集作用,重金属污染指数均＜1;土壤细菌数量显著增加;脲酶、磷酸酶和纤维素酶的活性增强;促进了萝卜的生长发育和代谢作用,萝卜的生物产量、经济产量、还原糖和维生素C的含量均明显提高,因此,适量施用该混合物未见导致重金属对土壤和萝卜的明显污染,且具有较明显的改土培肥、增产和提高萝卜品质的效果。     

Effects of Municipal Sewage Sludge Doses on the Chlorophyll Contents and Heavy Metal Concentration of Sugar Beet (Beta vulgaris var. saccharifera)

The present study was conducted to assess the suitability of sewage sludge amendment (SSA) in soil for Beta vulgaris var. saccharifera (sugar beet) by evaluating the heavy metal accumulation and physiological responses of plants grown at a 10%, 25%, and 50% sewage sludge amendment rate. The sewage sludge amendment was modified by the physicochemical properties of soil, thus increasing the availability of heavy metals in the soil and consequently increasing accumulation in plant parts. Cd, Pb, Ni, and Cu concentrations in roots were significantly higher in plants grown at 25% as compared to 50% SSA; however, Cr and Zn concentration was higher at 50% than 25% SSA. The concentrations of heavy metal showed a trend of Zn > Ni > Cu > Cr > Pb > Cd in roots and Zn > Cu > Ni > Cr > Pb > Cd in leaves. The only instance in which the chlorophyll content did not increase after the sewage sludge treatments was 50%. There were approximately 1.12-fold differences between the control and 50% sewage sludge application for chlorophyll content. The sewage sludge amendment led to a significant increase in Pb, Cr, Cd, Cu, Zn, and Ni concentrations of the soil. The heavy metal accumulation in the soil after the treatments did not exceed the limits for the land application of sewage sludge recommended by the US Environmental Protection Agency (US EPA). The increased concentration of heavy metals in the soil due to the sewage sludge amendment led to increases in heavy metal uptake and the leaf and root concentrations of Ni, Zn, Cd, Cu, Cr, Pb, and Zn in plants as compared to those grown on unamended soil. More accumulation occurred in roots and leaves than in shoots for most of the heavy metals. The concentrations of Cd, Cr, and Pb were more than the permissible limits of national standards in the edible portion of sugar beet grown on different sewage sludge amendment ratios. The study concludes that the sewage sludge amendment in the soil for growing sugar beet may not be a good option due to risk of contamination of Cr, Pb, and Cd.     

营养杯对长喙田菁在铅锌尾矿上的生长、固氮和重金属积累的影响

设置移栽时营养杯的有无及其大小作试验,研究长喙田菁在乐昌铅锌矿强酸化尾矿上的生长、固氮和积累重金属情况。结果表明,强酸性(pH<3)是限制植物定植的主要因素,在pH=5-7情况下,长喙田菁能在该尾矿库中定植、生长和固氮,表现出良好的适应性。未带营养杯移栽的长喙田菁在尾矿上生长84d,其株高117cm、茎基部直径1.35cm、单株生物量(干物质)20.2g、单位面积生物量(干物质)2828kghm-2、氮素积累量40kghm-2;带营养杯移栽的上述各指标分别达到140-144cm、1.59-1.68cm、36.6-38.8g、5124-5432kghm-2和77-107kghm-2,均显著高于未带营养杯处理的。长喙田菁根部铅、锌、铜、镉含量均最高,其次为茎,叶中最低;长喙田菁的4种重金属积累量为锌(186-221mgkg-1)>铅(96-145mgkg-1)>铜(17-30mgkg-1)>镉(3-4mgkg-1)。带营养杯移栽能有效提高长喙田菁的产量和氮积累量,且明显降低其体内的重金属含量。试验证明长喙田菁是较理想的铅锌矿尾矿废弃地植被重建的先锋植物。     

强还原过程对设施菜地土壤重金属形态转化的影响

设施菜地由于污水灌溉、粪肥施用等导致重金属污染.本文通过土柱淹水同时添加玉米秸秆培养和后期通水淋洗,研究强还原法对设施土壤重金属(Cd、Cu、Pb和Zn)形态转化的影响.结果表明: 强还原处理使土壤pH显著降低,玉米秸秆处理变化更显著;土壤氧化还原电位(Eh)迅速下降至-280 mV左右.玉米秸秆处理可以促进土壤中Cd、Cu、Pb和Zn活化,第9天土壤中有机物及硫化物结合态和残渣态Cd、Cu、Pb和Zn含量比重下降;至15 d培养结束,土壤中4种重金属含量较对照分别减少18.1%、19.0%、16.1%和15.7%.玉米秸秆处理可以增加土壤中Cd和Zn的溶出量,但是Cu的溶出量减少;胶体结合态Cd和Pb含量较对照增加、Cu较对照显著减少、Zn没有显著变化.强还原可以引起设施土壤重金属活化,提高蔬菜积累重金属的风险,而且其随土壤水分的运移可能导致水体的污染.     

龙胜县丘陵山区土壤与罗汉果重金属含量及潜在生态危害评价——以宝赠村为例

桂林市龙胜县作为罗汉果的三大主产区之一,种植区土壤重金属含量及罗汉果质量影响到该区罗汉果产业的健康发展。为探索龙胜县丘陵山区典型贫困村罗汉果园的安全性,该文研究了宝赠村典型罗汉果园土壤及罗汉果果实中砷、铜、锌、铅、镉、铬、汞7种重金属含量,并采用Hankanson指数法分析了其潜在生态风险。结果表明:(1)龙胜丘陵山区罗汉果园土壤(0~10 cm,10~20 cm)重金属含量均达到国家农业用地土壤筛选值标准(GB15618-2018),其中0~10 cm土壤中砷、铜、锌、铅、镉、铬、汞的含量分别为3.67、18.00、58.39、17.01、0.10、28.57、0.08 mg·kg^-1,10~20 cm土壤中砷、铜、锌、铅、镉、铬、汞的含量分别为1.93、12.56、21.47、10.51、0.04、17.09、0.02 mg·kg^-1。(2)在0~10 cm和10~20 cm土层中,重金属的生态风险状况总体上处于轻微生态风险等级,综合生态风险指数分别为105.29和38.96;0~10 cm土层不同重金属潜在的生态风险顺序为汞>镉>铅>铜>砷>锌>铬,汞、镉的生态风险分别为50.16、42.05,在总重金属风险中贡献率分别占所有重金属的47.6%和39.9%,已达中等生态风险等级;在10~20 cm土层中,7种重金属的生态风险大小关系为镉>汞>铜>铅>砷>铬>锌。(3)研究区罗汉果果实中砷、铜、锌、铅、镉、铬、汞的含量分别为0.00024、0.273、1.10、0.0016、0.00013、0.00013、0.00012 mg·kg^-1,其生态风险状况均处于轻微风险等级,7种重金属的生态风险顺序为汞>铜>镉>锌>铅>砷>铬,综合生态风险指数为0.21193,几乎不存在生态风险。因此,在龙胜县丘陵山区典型贫困村——乐江镇宝赠村推广种植的罗汉果达到了安全质量标准。     

蚯蚓对不同厚度复垦土壤中重金属生物有效性的影响

煤矸石充填复垦土壤理化状态和重金属水平能显著影响后续生态利用.为查明蚯蚓对矸石上不同厚度覆土中重金属(Cr、Cu、Pb和Zn)总量和有效态的影响,采用土柱实验,将蚯蚓接种到矸石上覆土,设置10、20、30、50、70 cm五种覆土厚度,通过测定不同厚度覆土pH、有机质(OM)、总氮(TN)、总磷(TP)、总钾(TK)和...     

城市绿化树种香樟不同器官对土壤重金属的富集特征

为了了解不同土壤重金属浓度梯度及污染梯度下香樟不同器官的富集特征,测定了香樟树叶、树枝、树干和根际土壤中6种重金属元素(Cu、Zn、Pb、Cr、Mn、Ni)的含量.结果表明: 香樟地上部分重金属含量因器官、元素种类、根际土壤重金属浓度的不同而存在差异.香樟树叶和树枝重金属含量的大小顺序均为:Mn＞Zn＞Cu＞Cr＞Pb＞Ni,树干重金属含量为:Mn＞Zn＞Cr＞Pb＞Ni＞Cu.树叶对Mn的富集系数较高,为2.409;树干对Ni的富集系数较高,分别为树叶、树枝的8.6和17倍,且在不同土壤重金属浓度梯度下,香樟树干对Cu、Zn、Pb、Cr、Ni的富集系数均明显高于其他器官.香樟地上部分器官对Cu、Zn、Pb、Cr、Mn、Ni 6种重金属元素的综合富集能力大小顺序为:树叶＞树干＞树枝.随着土壤重金属污染等级的增加,香樟地上部分各器官的富集系数均逐渐降低.研究区域平均胸径为22 cm的单株香樟对重金属元素富集效能的大小顺序为:树叶＞树干＞树枝,其中树干对Cu、Zn、Pb、Cr、Ni的积累量均显著高于树叶和树枝.表明香樟对6种重金属元素均有一定的富集能力,并且树干对Pb和Ni的富集效能明显,分别占地上部分总积累量的82.7%和91.9%,能很好地富集并稳固土壤中的Pb和Ni,可作为修复治理土壤重金属污染的备选树种.     

金属矿区芒草种群对重金属的积累及其与土壤特性的关系

通过分析大型综合金属矿区中经历不同污染强度与污染时间胁迫的芒草（Miscanthus sinensis）种群对4种主要重金属的积累状况,初步揭示芒草对这些重金属的积累特性与土壤重金属含量的关系。结果表明,1芒草根茎叶对4种重金属的的积累顺序为：根〉叶〉茎;2芒草对Cd、Pb的积累量与土壤中这两种重金属含量之间存在显著（P〈0．05）正相关关系;对Cu、Zn的积累量与土壤含量之间无显著相关,主要是因为土壤最高Cu与Zn含量已超过芒草对这两种元素积累所需的最大量,成为对芒草构成胁迫的主要因子。在该矿区的酸性条件下,芒草对Pb、Zn、Cu3种重金属的吸收率随pH值升高而升高,pH接近的样地,芒草的吸收率主要受土壤重金属含量的影响。结合各种群对四种重金属的积累状况判断,强度胁迫下的种群可能已发生耐性分化,从而产生较其它种群更强的耐重金属特性。总体上芒草是一种多重金属耐性植物,对这四种重金属的耐性顺序是：Cd〈Cu〈Zn-Pb。     

芜湖钢铁厂周边土壤及油菜籽中镉、铜、锌、铅含量和形态分布研究

研究了污染土壤、油菜籽中Cd、Cu、Zn、Pb含量、形态分布特征和重金属富集状况及可能存在的生物毒性.结果表明,土壤中Cd、Zn、Pb以铁锰氧化物结合态、Cu以残留态占5种形态最高比例,分别为31.1%、39.3%、53.79%、46.24%;Cd、Pb交换态比例较高,为23.47%、16.32%,Cu、Zn的交换态比例较小,为3.14%、0.54%;土壤中不同重金属与各重金属形态相关关系有差别,5种重金属形态转化为有效态重金属难易程度不同;油菜籽和油菜籽壳中不同重金属累积趋势有差异,Cu易在油菜籽壳中累积,Cd、Zn、Pb易在油菜籽中累积;油菜籽中不同重金属累积率不同,Cd累积率最高,为0.56.油菜籽中重金属累积率与土壤中重金属总量呈显著负相关关系(P＜0.05),土壤中重金属的形态、转化差异是此种负相关关系的主要原因;油菜籽中Cd、Cu、Pb以氯化钠态为主,分别为32.50%、22.94%、34.69%,Zn以EDTA态为主,为45.97%.油菜籽中重金属形态可能影响其毒性,但其毒性的人类膳食风险还需进一步研究证实.油菜籽中重金属形态与油菜中重金属总量相关性不好.     

典型城市单元的土壤重金属溯源方法与实证研究

随着城市化进程的不断深入,土壤中重金属污染现状及其治理情况越来越受到重视,而查明污染源是有效治理污染的前提。源解析技术目前已广泛的应用于环境受体重金属来源解析实践中,总结了近年来土壤重金属成因分析的常用方法及原理,并提出了一种将多种方法相配合使用的方法体系。选取珠三角某市城郊农田作为研究对象,结果表明,Cd、Pb、Cu、Zn、As存在含量超过国家农用地筛选值的情况,其中Cd超标率高达60.1%。农业活动、工业生产、交通源和自然母质均对研究区土壤重金属的累积产生一定的贡献。正定矩阵因子分析法(PMF,Positive Matrix Factorization)模型模拟的Cd、Ni、Zn和Hg预测值与实测值线性拟合r~2均大于90%,其余元素r~2均大于60%,呈现出很好的相关性,满足研究需要。PMF模型和铅同位素比值法计算得到的交通及农业对土壤Pb累积的贡献率之和分别为86.0%和84.8%,PMF模型和物质流分析法计算得到的农业对土壤Cd的贡献率分别为86.7%和79.7%,结果均比较接近。结果表明正定矩阵因子法、同位素比值分析法,物质流分析法能很好的联用应用于土壤重金属源解析研究。     

Health Risks Assessment of Heavy Metal Pollution in the Soil-Crop System from an E-Waste Dismantling Area

Soil is an essential resource for agricultural production. In order to investigate the pollution situation of heavy metals in the soil-crop system in the e-waste dismantling area, the crop and soil samples (226 pairs, including leaf vegetables, solanaceous vegetables, root vegetables, and fruits) around the e-waste dismantling area in southeastern Zhejiang Province were collected. The concentrations of Cd, Cu, Pb, and Cr were determined. The average concentrations of Cd, Cu, Pb, and Cr in soils were 0.94, 107.79, 80.28, and 78.14 mg kg^-1, respectively, and their corresponding concentrations in crops were 0.024, 0.7, 0.041, and 0.06 mg kg^-1, respectively. The transfer capacity of leaf vegetables was significantly higher than that of non-leaf vegetables, and the accumulation of four heavy metals in crops tended to be Cd > Cu > Cr/Pb. The pollution index’s results revealed that the soil pollution degree under different land uses ranked as root vegetables soil > leaf vegetables soil > solanaceous vegetables soil > fruit soil. The carcinogenic and non-carcinogenic risks of heavy metal exposure were ranked as food intake > accidental ingestion > dermal contact > inhalation. The comprehensive non-carcinogenic risk was ranked as Cr > Cd > Pb/Cu. Our results could be used to provide useful information for further crop cultivation layout in the study area, which can guarantee the local residents’ health and food safety.

     

铜尾矿区土壤与凤丹植株重金属富集研究

对安徽铜陵铜尾矿区凤丹种植地的土壤和凤丹中重金属污染状况进行了研究,结果表明,尾矿库区种植地极端贫瘠,有机质含量仅1．1～3．4g·kg^-1,而土壤Cu、Cd、Pb、Zn含量皆高于对照土壤,其中Cu含量达587．43～1176．44mg·kg^-1,Cd含量达3．08～5．16mg·kg^-1,约达国家土壤二级标准的10倍,凤丹各部位的Cu、CA和Pb含量均超过了药用植物的限量标准,尤其是根皮部位Cu含量达31．50～64．00mg·kg^-1,Cd含量达0．98～1．45mg·kg^-1,超出标准1．6～3．6倍,表明种植地和凤丹都受到严重污染．凤丹不同部位中的Zn、Cd、Pb和Cu分别以茎、叶、叶和根皮中的含量最高．凤丹对Cd、Zn的富集比Cu和Pb高,但在根皮中的富集系数均较小。     

污染条件下VAM玉米元素积累和分布与根际重金属形态变化的关系

为了了解重金属Cu、Zn、Pb、Cd在土壤－根际－植物系统中的行为,揭示VAM植物减弱土壤中过量重金属对植物生理毒的抗性机理,采用原子吸收光谱测定Cu、Zn、Pb、Cd在污灌土壤中生长的VA菌根玉米和无菌根玉米中的积累和分布,并用连接形态分析技术分析了菌根际中Cu、Zn、Pb、Cd的形态分布和变化趋势,结果表明,Cu、Zn、Pb、Cd在菌根玉米中的积累量比非攻根中积累量分别减少10％、18％和29％,Cd积累量没有改变,生长7周后,菌根玉米是非菌根玉米生物量的1．5倍,与对照土壤相比,根际中除Cu交换态显著增加外,Zn、Pb、Cd各形态相对改变量显著大于非菌根,且菌根根际上中Cu、Zn、Pb有机结合态增加量显著大于非根际土,说明菌根际金属向稳定状态转移的程度显著大于非菌根际,同时,讨论了根际金属形态对金属有效性的影响,及其与菌根植物金属抗性机理的关系。     

佛山城市典型森林群落土壤重金属分布、流通及枯落物富集特征

富集重金属的枯落物分解可能提高重金属暴露率,增加人体接触健康风险。为了解南方城市土壤重金属在森林生态系统中的分布及流转情况,通过调查研究了佛山市8个典型森林群落土壤及枯落物重金属含量,分析了各森林群落枯落物对不同重金属的富集效应及重金属随枯落物回归土壤流通量。结果表明：1）城市森林各土壤重金属含量在不同典型群落间差异显著（P<0.05）,差异最大为Pb、Cr、Zn,As、Cu、Ni次之,Hg、Cd最小;土层深度（0-20,20-40,40-60 cm）对重金属含量影响显著（P<0.05）,差异最大为Cd、Hg,其次为As、Cu,最小为Zn、Ni、Pb、Cr。整体上,Cd、Hg、As、Pb、Zn在0-20 cm最高,表层富集特征明显,Cr和Ni在40-60 cm最高。2）8个森林群落中阴香-白楸-醉香含笑群落（CMMC）枯落物对8种重金属的综合富集系数（TBCF,66.76）最高,其中以Cd的富集效果最突出,富集系数为44.45,且对Pb、Cu、Zn也相对富集;最低的为黧蒴锥-香椿-樟树群落（CTCC）,综合富集系数（TBCF）为8.09,仅对Cd、Cr、Cu相对富集,对其余重金属富集效应不明显。3）相关分析显示,群落重金属枯落物流通量与0-60 cm土壤重金属平均含量（Cr和Ni除外）无显著相关性。本研究对城市森林建设管理及筛选重金属富集植物及群落具有较强理论及实践意义。     

Heavy Metal Contamination in Roadside Soil and Their Mobility in Relations to pH and Organic Carbon

Concentrations of Pb, Zn, Cd, Ni, Cu, Cr, and Mn were determined to assess the impact of automobiles on heavy metal contamination of roadside soil. Soil samples at four polluted sites and a control site were collected at a depth of 0, 2, 5, 10, 15, 20, 30?cm. A comparison of elemental levels between polluted and control sites exhibited exceptionally higher concentrations at the former sites. The Pb levels in polluted sites varied from 70 to 280.5?µgg^?1and it rapidly decreased with depth. Similarly, mean concentrations of Zn, Cd, Ni, Cu, Cr, and Mn were significantly higher at polluted sites and followed a decreasing trend with the increase in depth. Correlation coefficients between heavy metals and traffic density were positively significant except for nickel. Profile samples showed that Pb, Zn, Cd, Cu, and Mn were largely concentrated in the top 5?cm confirming airborne contamination. The vertical movement and partitioning of metals, except Ni and Cr, exhibited predominant association with soil pH and organic carbon. The results have been presented using Heavy Metal Index.     

The accumulation characteristics and potential health risks of heavy metals in vegetables from reclaimed area of China

The reclamation of subsidence area was regarded as a useful pathway to rebuild landscape and ecosystem. However, the elevated concentrations of heavy metals in the reclaimed area may lead to potential environmental and health risks. This study was aimed at investigating the accumulation of heavy metals in the soils and vegetables, and evaluate the potential health risks to human beings via consuming these vegetables. The concentrations of heavy metals (Cd, Cu, Pb, and Zn) were measured by using inductively coupled plasma mass spectrometry. The elevated concentrations of heavy metals were found in the soil from the reclaimed area when compared with the background value. The concentrations of heavy metals were various among the different vegetable species. The heavy metal tolerance could be found in all the selected vegetables. The elevated concentrations of Cu, Pb, and Zn in the edible part of the selected vegetables indicated that the consumption of these vegetables may lead to potential health risk. The intake of soybean, radish, sweet potato, and mugwort may lead to potential health risks due to the elevated target health quotients. Chinese cabbage and pepper were regarded as the suitable vegetables which may help in reducing the potential health risk.     

交通要道重金属污染对农田土壤动物群落结构及空间分布的影响

为了解交通要道重金属对路边农田土壤动物群落结构及空间分布的影响,分季节分层次对104国道浙江上虞段周围农田5条样带及1条对照样带进行取样调查,共获得土壤动物4046个,计50个类群,隶属于4门7纲,弹尾目、前气门亚目、甲螨亚目为优势类群,其余为常见类群和稀有类群。同时测定了采样带土壤理化性质和重金属含量,结合类群特征指数,研究农田土壤动物群落结构特征以及土壤动物对土壤重金属污染的响应。结果表明,6条样带土壤理化指标全磷和pH、重金属各因子差异显著(P0.05),公路周围重金属含量明显高于对照和土壤背景值,随着采样距104国道的距离的减小,土壤动物的类群数和个体数呈现减少的趋势,在土层垂直分布上,并呈现表聚性减弱的现象。灰色关联分析表明,在调查样带中全磷对土壤动物的影响最大,土壤pH次之,其次是铅、铬的影响,锌的影响最小。土壤理化指标全磷和pH对农田土壤动物的影响大于土壤重金属,但重金属对污染样带土壤动物群落结构的影响已不能忽视。     

Distribution and Risk Assessment of Heavy Metals in the Xinzhuangzi Reclamation Soil from the Huainan Coal Mining Area,China

The contamination of coal-mine soil by heavy metals is a widespread problem. This study analyzes the heavy metals (Cu, Zn, Ni, Pb, Cr, Cd, and Hg) found in 33 surface soil samples from Xinzhuangzi, China restored coal-mining land used as cultivated land. The results show that the selected elements were cumulative, especially for Cd. An index of geo-accumulation indicates that the soil was practically uncontaminated by Cu, Zn, Ni, and Hg, uncontaminated to moderately contaminated by Pb and Cr, and moderately to heavily contaminated by Cd. Based on the U.S. Environmental Protection Agency's ecological soil screening levels (Eco-SSLs) for Cu, Zn, Ni, Pb, and Cd and the Dutch Target and Intervention Values for Cr and Hg, the plants and soil invertebrates were not likely greatly influenced by the selected metals. Although the Cd concentration was found to have no significant effect on plants and soil invertebrates, it is the only metal with a concentration significantly above that required by Chinese standards (HJ/T 332–2006) for edible agricultural products, indicating that Cd is the predominant factor that determines the use of the reclaimed coal-mining area for farmland. Thus, employing the reclaimed land as farmland may not be a good option.