铅锌矿区农田土壤重金属有效态空间分布及其影响因子分析

利用地统计学方法,研究了广西岩溶地区某铅锌矿区农田土壤中Cd、Zn、Pb、Cu四种重金属有效态含量的空间分布特征及其影响因子.结果表明:研究区域不同程度地受到Cd、Zn、Pb、Cu的污染,且水田污染较旱地严重;与广西土壤背景值相比,污染程度最严重的是Cd,在水田和旱地中超标率均为100%,平均超标倍数分别为312.94和33.67;其次是Zn,在水田和早地中超标率分别为100%和34%,平均超标倍数分别为38.34和2.11;污染最轻的为Cu,超标率仅为7%.空间分析表明,有效态Cd、Zn、Pb、Cu的块金系数分别为2.7%、0.2%、6.5%、0.13%,体现了强烈的空间自相关性,且四种重金属空间分布特征相似,在离原铅锌选矿厂较近的西北偏西面有效态Cd、Zn、Pb、Cu含量最高,沿着西北偏西至东南偏东的灌溉渠流向,有效态Cd、Zn、Pb、Cu的含量呈递减趋势,东部旱地有效态Cd、Zn、Pb、Cu含量相对较低.土壤有效态Cd、Zn、Pb、Cu在污染区的空间分布与土壤基本理化性质关系密切,有效态Cd、Zn、Pb、Cu与pH、阳离子交换量、粘粒都呈极显著负相关,与有机质含量则呈极显著正相关.     

淋洗脱盐对滨海滩涂不同植被演替带土壤重金属的影响

为研究围垦对滨海滩涂土壤重金属的影响,采用土柱实验模拟淋洗脱盐过程,分析了滨海滩涂不同植被演替带(光滩、互花米草滩、碱蓬滩、芦苇滩)土壤在淋洗脱盐前后重金属(As、Hg、Cd、Cr、Pb、Cu、Zn)含量的变化,评估了围垦可能导致的滩涂重金属流失量。研究表明,淋洗脱盐后,各植被演替带土壤重金属均显著降低,相比而言,Hg、Cr更易淋洗(淋洗率分别为57.2%、49.9%),而Zn不易淋洗(淋洗率18.5%);不同植被演替带土壤重金属淋洗率表现为:光滩互花米草滩碱蓬滩芦苇滩,光滩土壤重金属更易淋洗,而芦苇滩重金属不易淋洗;根据土壤容重、含水率、淋洗率及重金属含量计算重金属流失量发现,不同植被演替带重金属流失量同样表现为:光滩互花米草滩碱蓬滩芦苇滩;除互花米草滩As流失量较高外(19.26 kg·ha-1),其他重金属流失量均表现为光滩最高,光滩围垦可能会造成更多的重金属流失;在仅考虑淋洗脱盐情况下,以江苏省2010~2020年围垦规划270万亩计,仅表层20 cm滩涂土壤,通过围垦即可能导致As、Hg、Cd、Cr、Pb、Cu、Zn流失2 102.5、7.4、421.3、8 587.9、4 376.3、2 404.3 t,由围垦导致的滩涂重金属流失风险值得关注。     

TCLP法评价酸性矿山废水污染稻田土壤重金属的生态风险

采用美国最新的法定重金属污染评价方法TCLP(Toxicity Characteristic Leaching Procedure,TCLP)法对粤北大宝山矿山下游受酸性矿山废水长期污染的稻田土壤的重金属(Cd、Zn、Pb、Cu)污染状况进行评价,以国际规定的TCLP法标准评价重金属生态环境风险.结果表明,TCLP试剂提取的土壤重金属Cd、Cu、Pb和Zn含量分别在0.02～0.58、1.42～38.07、0.16-31.01和1.84～75.29 mg·kg-1之间.酸性矿山废水污染稻田土壤不同程度地受到Cd、Cu、Pb、Zn的污染,其中以Pb、Zn污染最为严重,其次为Cu污染,Cd污染程度最轻.     

Enrichment and solubility of trace metals associated with magnetic extracts in industrially derived contaminated soils

Magnetic fractions (MFs) in industrially derived contaminated soils were extracted with a magnetic separation procedure. Total, soluble, and bioaccessible Cr, Cu, Pb and Zn in the MFs and non-magnetic fractions (NMFs) were analyzed using aqua regia and extraction tests, such as deionized water, toxicity characteristic leaching procedure (TCLP), and gastric juice simulation (GJST) test. Compared with the non-magnetic fractions, soil MFs were enriched with Fe, Mn, Pb, Cd, Cr, Cu, and Ni. Extraction tests indicated that soil MFs contained higher water, TCLP, and GJST-extractable Cr, Cu, Pb, and Zn concentrations than the soil NMFs. The TCLP-extractable Pb concentration in the MFs exceeded the USEPA hazardous waste criteria, suggesting that soil MFs have a potentially environmental pollution risk. Solubility of trace metals was variable in the different extraction tests, which has the order of GJST?>?TCLP?>?water. TCLP test showed Cu and Zn were more mobile than Cr and Pb while bioaccessibility of trace metal defined by GJST test showed the order of Cu?≈?Cr?≈?Zn?>?Pb. These findings suggested that the MFs in the industrially derived contaminated soils had higher possibility of polluting water bodies, and careful environmental impact assessment was necessary.     

Biosolids application affects the competitive sorption and lability of cadmium,copper, nickel,lead, and zinc in fluvial and calcareous soils

The objective of this research was to investigate the effects of biosolids on the competitive sorption and lability of the sorbed Cd, Cu, Ni, Pb, and Zn in fluvial and calcareous soils. Competitive sorption isotherms were developed, and the lability of these metals was estimated by DTPA extraction following their sorption. Sorption of all metals was higher in the fluvial than in the calcareous soil. Sorption of Cu and Pb was stronger than that of Cd, Ni, and Zn in all soils. Biosolids application (2.5%) reduced the sorption of all metals especially Cu and Pb (28–43%) in both soils (especially the calcareous soil) at the lower added metal concentrations (50 and 100 mg L^?1). However, it increased the sorption of all metals especially Pb and Cu in both soils (especially the calcareous soil; 15.5-fold for Cu) at the higher added concentrations (250 and 300 mg L^?1). Nickel showed the highest lability followed by Cd, Zn, and Pb in both soils. Biosolids increased the lability of the sorbed Ni in the fluvial soils at all added concentrations and the lability of Cd, Pb, and Zn at 50 mg L^?1, but decreased the lability of Cd, Pb, and Zn at 250 and 300 mg L^?1 in both soils. We conclude that at low loading rate (e.g., 50 mg L^?1) biosolids treatment might increase the lability and environmental risk of Cd, Cu, Pb, and Zn. However, at high loading rate (e.g., 300 mg L^?1) biosolids may be used as an immobilizing agent for Cd, Cu, Pb, Zn and mobilizing agent for Ni.     

Phylogenetic analysis of hyperaccumulator plant species for heavy metals and polycyclic aromatic hydrocarbons

Increasing concentration of heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) in the soil may impose a serious threat to living organisms due to their toxicity and the ability to accumulate in plant tissues. The present review focuses on the phylogenetic relationships, sources, biotransformation and accumulation potential of hyperaccumulators for the priority HMs and PAHs. This review provides an opportunity to reveal the role of hyperaccumulators in removal of HMs and PAHs from soils, to understand the relationships between pollutants and their influence on the environment and to find potential plant species for soil remediation. The phylogenetic analysis results showed that the hyperaccumulators of some chemicals (Co, Cu, Mn, Ni, Zn, Cd) are clustered on the evolutionary tree and that the ability to hyperaccumulate different pollutants can be correlated either positively (Cd–Zn, Pb–Zn, Co–Cu, Cd–Pb) or negatively (Cu–PAHs, Co–Cd, Co–PAHs, Ni–PAHs, Cu–Ni, Mn–PAHs). Further research needs to be extended on the focus of commercializing the techniques including the native hyperaccumulators to remediate the highly contaminated soils.

     

有机酸与表面活性剂联合作用对土壤重金属的浸提效果研究

重金属污染土壤的原位淋洗修复既要实现对重金属的高效去除,还要尽量减少对土壤性质的破坏,这一点在农业污染土壤修复中尤为重要。以张士污灌区农田土壤为研究对象,利用振荡浸提技术筛选有机酸和表面活性剂组合,并确定了两者联合淋洗修复污染土壤的最佳配比。结果表明：有机酸（酒石酸、乙酸、柠檬酸和苹果酸）中的酒石酸浓度为0.5 mol.L-1和表面活性剂（SDBS、鼠李糖和皂素）中的皂素质量分数为0.7%时对土壤Cd、Pb、Zn的浸提效果较好;在酒石酸与皂素体积配比为1∶1时,对重金属Cd、Pb、Zn浸提效果最好,浸提率分别为87.62%、36.30%、20.67%;单一有机酸、表面活性剂或者有机酸与表面活性剂的混合溶液,对土壤重金属的浸提效果均为Cd〉Pb〉Zn。虽然有机酸与表面活性剂联合浸提效果略低于酒石酸浸提,但其弱酸性对土壤性质影响较小,在原位淋洗修复工程中有较好的应用前景。     

Sources and risk assessment of metal contamination in soils at the international airport of Shanghai,China

Concentrations of Cd, Pb, Zn, Cr, Cu, and Ni in soils at the Pudong International Airport (PIA) of Shanghai, China, were determined to assess the sources and potential ecological risks. Compared to the soil background values of Shanghai, 31 soil samples out of 33 were highly contaminated with Cd, and 76% were moderately contaminated by Cr, Ni, Pb, and Zn. Principal component analysis and clustering analysis indicated that Pb and Cd mainly originated from anthropogenic sources, while Zn, Cr, Ni, and Cu were mainly from natural sources. Relatively high concentrations of Cd and Pb were observed at sampling points near the landing or take-off sites or a close-by highway. Both air and highway traffic affected the quality of the soils at PIA.     

Urban Geochemistry: A Multimedia and Multielement Survey of a Small Town in Northern Europe

The concentrations and distributions of chemical elements (Ag, Al, As, Au, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, Hg, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sc, Se, Sr, Te, Th, Ti, Tl, U, V, W and Zn) were studied in till, humus and urban soil in Jakobstad, a small town (20,000 inhabitants) in W. Finland. The analyses were performed with ICP-MS after aqua regia leaching of till (n = 37), urban topsoil (n = 32) and subsoil (n = 32), and HNO3 leaching of humus (n = 37). The till and humus samples, collected at the same sites, were divided into urban and rural samples. The urban till was not significantly enriched in metals. In contrast, a majority of the elements occurred in higher concentrations in the urban than the rural humus samples. Statistical and spatial interpretations of the humus data revealed that traffic (Pb, V and Ni), metal industry (Pb, Zn, Bi, Sb and Cr), an abandoned shooting range (Pb and Sb) and other sources contribute to higher metal levels in the urban humus. The urban soil samples were collected at parks, yards, abandoned industrial sites, roadsides, etc. The topsoil samples were enriched in most elements, also by elements not enriched in the urban humus (e.g. Cd). At several sites, the concentrations far exceeded the limit concentrations for contaminated soils in Finland. A large variety of sources were identified or indicated.     

Contamination indices and heavy metal concentrations in urban soil of Ibadan metropolis, southwestern Nigeria

An assessment was conducted on soils of Ibadan metropolis using geochemical approach in order to establish the concentration of heavy metals and develop geoaccumulation index maps. Petrographic studies and X-ray diffractograms showed that soils of Ibadan were derived from the weathering of the bedrocks. The concentrations of Cu, Pb, and Zn were found to be greater in soils more than the background. Positive correlation occurred between Cu, Pb, and Zn indicated a common anthropogenic source in the soil while Mn, Cr, and Ni were found to be naturally enriched. The geoaccumulation index maps revealed significant enrichment factor (Ef > 20) and index of geoaccumulation (Igeo) beyond class four (heavily contaminated) for Cu, Pb, and Zn in densely populated and industrial areas, whereas Cd is enriched in sparsely populated areas, agricultural areas and a few spots in densely populated areas.     

Accumulation and translocation of heavy metals in soil and plants from fly ash contaminated area

The present investigation deals with the accumulation of heavy metals in fields contaminated with fly ash from a thermal power plant and subsequent uptake in different parts of naturally grown plants. Results revealed that in the contaminated site, the mean level of all the metals (Cd, Zn, Cr, Pb, Cu, Ni, Mn and Fe) in soil and different parts (root and shoots) of plant species were found to be significantly (p<0.01) higher than the uncontaminated site. The enrichment factor (EF) of these metals in contaminated soil was found to be in the sequence of Cd (2.33) > Fe (1.88) > Ni (1.58) > Pb (1.42) > Zn (1.31) > Mn (1.27) > Cr (1.11) > Cu (1.10). Whereas, enrichment factor of metals in root and shoot parts, were found to be in the order of Cd (7.56) > Fe (4.75) > Zn (2.79) > Ni (2.22) > Cu (1.69) > Mn (1.53) > Pb (1.31) > Cr (1.02) and Cd (6.06) approximately equal Fe (6.06) > Zn (2.65) > Ni (2.57) > Mn (2.19) > Cu (1.58) > Pb (1.37) > Cr (1.01) respectively. In contaminated site, translocation factor (TF) of metals from root to shoot was found to be in the order of Mn (1.38) > Fe (1.27) > Pb (1.03) > Ni (0.94) > Zn (0.85) > Cd (0.82) > Cr (0.73) and that of the metals Cd with Cr, Cu, Mn, Fe; Cr with Pb, Mn, Fe and Pb with Fe were found to be significantly correlated. The present findings provide us a clue for the selection of plant species, which show natural resistance against toxic metals and are efficient metal accumulators.     

Risk assessment for safety of soils and vegetables around a lead/zinc mine

Concentrations of heavy metals (Pb, Zn, Cd, Cu) were determined in soils and vegetables (chrysanthemum, spinach and four cultivars of Chinese cabbage from the area adjacent to a Pb/Zn mine in Shaoxing, Zhejiang province, China, and compared with the Chinese National Standards for Soil Environmental Quality. The accumulation of heavy metals in cabbage cv. Siyuegreen was investigated at different distances from the center of the mine. The vegetable plantation soils were polluted with Pb, Cd, Cu and Zn, especially by Pb and Cd. The levels of Pb and Cd were 20 and 30 times higher than the permitted standards, indicating that this Pb/Zn mining area is unsuitable for agricultural use. Chinese cabbage, chrysanthemum and spinach had different enrichment coefficients. The enrichment coefficient of Cd from soil to roots of chrysanthemum was >80% and from roots to leaves of cabbage cv. Shanghaigreen was >120%. These vegetables were polluted by heavy metals and could not be regarded as safe for human consumption. Environmental accumulation of heavy metals in the vegetable plantation soils was proportional to heavy metal accumulation in vegetables and both were inversely proportional to the distance from the lead/zinc mine.     

Assessment of toxicity of heavy metal contaminated soils by the toxicity characteristic leaching procedure

The concentrations of Cu, Zn, Pb and Cd in soils near a lead–zinc mine located in Shangyu, Zhejiang Province, China, were determined and their toxicity was assessed using the toxicity characteristic leaching procedure (TCLP) developed by the United States Environmental Protection Agency. The TCLP method is a currently recognized international method for evaluation of heavy metal pollution in soils. The available levels of Cu, Zn, Pb and Cd were 8.2–36, 23–143, 6.4–1367 and 0.41–2.2 mg kg⁻¹, respectively, while the international standards were 15, 25, 5 and 0.5 mg kg⁻¹, respectively. Soils around the mine were more polluted with Zn and Pb, followed by Cd and Cu. Moreover, the levels of heavy metals in the soils extracted by TCLP indicated that extraction fluid 2 was more effective than extraction fluid 1 in extracting the heavy metals from the polluted soils and there was a positive correlation between fluids 1 and 2. Available heavy metal contents determined by TCLP were correlated with soil total heavy metal contents.     

溶解性有机物对土壤中重金属环境行为的影响

为揭示在溶解性有机物（DOM）作用下土壤中重金属的吸附和迁移规律并确定迁移数学模型,通过不同条件下的等温吸附实验和土柱淋滤实验,研究了溶解性有机物对重金属Cu,Cd,Pb,Zn在褐土中吸附和迁移行为的影响。结果表明DOM对Cu和Cd在土壤中的吸附促进作用较明显,对Pb有微弱的促进作用,对Zn的吸附影响不明显;随着pH的改变,25℃下Cu在土壤中的吸附高于15℃和35℃条件下。DOM质量浓度越高,Cd、Zn溶出的促进效果越明显,Cu、Pb则恰好相反。DOM对土壤中Cd、Zn的垂直迁移起着促进作用,而对Cu、Pb迁移起着一定的抑制作用;DOM对土壤重金属的平均迁移量随时间的延长而减少。此迁移模型能够定量计算并预测重金属质量浓度的时空分布。     

Some characteristics of the distribution of heavy metals in urban topsoil of Xuzhou,China

An assessment is presented of distribution characteristics of heavy metals in the urban topsoil from the city of Xuzhou. The concentrations of Ag, Al, As, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Fe, Ga, Hg, Li, Mn, Mo, Ni, Pb, Pd, Pt, Sb, Sc, Se, Sn, V and Zn have been determined from 21 soil samples. Examination of lognormal distribution plots indicates that the diagrams of Al, Be, Fe, Ga, Li, and V are almost linear suggesting that these metals are almost unaffected by anthropogenic activities while the plots for As, Cd, Cu, Pb, Pd, Pt, Se, Zn and others are not linear probably due to anthropogenic activities from which these metals are delivered to the soils. Al is used for mineralogical normalization of these data. An evaluation of background values for topsoil is also carried out by means of lognormal distribution plots. The results show our background values obtained from the lognormal distribution plots are comparable to those values of uncontaminated soils of Xuzhou obtained by previous work except for Cd and Hg. At present, no explanation for the exceptions Cd and Hg can be given.     

烟气脱硫石膏对滩涂围垦土壤重金属解吸及残留形态的影响

滩涂围垦土壤是重金属等难降解污染物的主要最终归宿场所之一,其重金属的解吸将影响重金属的迁移性、生物有效性和潜在毒性,研究重金属的解吸对土壤污染评价、修复及环境容量预测至关重要.研究了烟气脱硫石膏对广州市南沙滩涂围垦土壤重金属的解吸效果,并分析了烟气脱硫石膏对重金属形态的影响.在离心管中称取20.0 g过0.25mm筛土样,加入20 mL水和不同量的烟气脱硫石膏,在室温下于恒温振荡器振荡,风干研碎后用原子吸收分光光度法测定重金属全量,并用Tessier连续提取法研究了处理前后重金属形态变化.研究结果表明,随着脱硫石膏施用量的增加,经过振荡离心后的滩涂围垦土壤中重金属质量分数先急剧下降,之后变化趋于平缓.与原土相比各重金属最大解吸率分别为:Cd 30.38%,Cu17.73%,Ni 15.00%,Zn 14.19%,Pb 9.46%,Cr 8.89%.比较处理前后重金属的形态变化,发现各重金属的可交换态解吸率均达50%以上,并且重金属碳酸盐结合态质量分数也有减少.说明烟气脱硫石膏能降低土壤对重金属的吸附,经振荡离心后能降低土壤中重金属的毒性和生物可利用性.     

Metal contamination of soils and dusts in Seoul metropolitan city,Korea

To investigate the dispersion patterns and the characteristics of heavy metal contamination due to urbanisation and industrialisation, soils and dusts collected from the Seoul area were analysed for Cu, Pb, Zn and Cd. The metal concentrations in most soils and dusts are higher than the world averages. The pollution index (( Metal concentrations in soils/Permissible level for metal)÷(Number of metals)) of soils and dusts is > 1 in most of the Seoul area, a result that concurs with the industrialisation and urbanisation index of the Seoul area. The soils are contaminated with Cu, Zn, Cd and particularly Pb. This suggests that the contamination of the soils in the Seoul area are mainly caused by vehicular emissions. The pollution index of soil is the highest in the Kuro area where Cu and Zn contamination in soils are due to the indigenous brass and bronze factories. From the discriminant analysis, the Seoul area may be partitioned into control, traffic and industrialized areas by the metal concentrations in the order of Zn > Cu > Pb.     

合肥市城市土壤重金属元素含量及空间分布特征

研究了合肥市城市土壤中重金属的含量、空间分布特征及来源。结果表明,合肥市城市土壤中,Ni和As2种元素污染不明显,但受到Cu、Zn、Pb、Sr、Cd、Hg6种元素不同程度的污染,其中Hg污染最严重。Ni和As2种元素的分布主要受自然因素影响,Cu、Zn、Pb、Sr、Cd、Hg6种元素主要来源于人为输入。Zn,Cd,Pb3种元素的空间分布规律比较相似,表现为在东部工业区和老城区内明显出现富集。Cu和Hg2种元素在合肥市城市土壤中含量的分布规律比较相似,峰值出现在东部工业区、老城区、北部和南部交通干线交汇区。Zn、Cd、Pb、Cu、Hg5种元素可能主要来源于工业活动和交通污染。Sr元素峰值出现在老城区和工业区中间,主要交通干线沿线和交汇地区含量也较高,Sr元素可能主要来源于交通污染。     

EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta)

Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.     

东莞市不同区域菜地土壤重金属污染状况研究

对东莞市及其不同区域菜地土壤重金属污染情况进行了调查和分析，参照国家土壤环境质量标准，运用单因子污染指数法和综合污染指数法对上述土壤质量进行了评价。结果表明，全市和各区土壤受到了不同程度的重金属污染，具体表现为：全市土壤Cd、Cu、Ni和Pb的超标率分别为4．9％，6．6％，3．3％和95．1％，均处于轻污染状态，以Pb污染最严重；土壤Cr未有超标，仅西北区域达到了警戒级水平。全市土壤重金属含量各样点间变异较大(Zn、Cr、Pb、Cd、Cu、Ni和有效Cu、Zn的变异系数分别为51．5％，54．1％，37．5％，48．8％，60．2％，57．3％和85．3％，64．7％)，但对各重金属元素而言却存在着不同程度的区域差异。