Effects of land use on concentrations of metals in surface soils and ecological risk around Guanting Reservoir,China

It is accepted that the historical routine use of agrochemicals may have resulted in undesirable concentrations of metals in the environment. To investigate and assess the effects of land use on concentrations of heavy metals around the Guanting Reservoir in China, 52 surface soil samples (depth of 2–10 cm) were taken from areas where four types of land use were practiced (including arable land, woodland, bare land, orchard land). The metals and metalloids (As, Cr, Ni, Cu, Zn, Cd, and Pb) were analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Significant accumulation of As, Cd, and Cr was found in soils of arable land. Based on correlation and cluster analysis, it can be concluded that Cd and Zn originate mainly from phosphate fertilizer, Pb from the use of insecticides, fertilizers, and sewage sludge as well as air deposition, and Cu from copper-based fungicides, while As, Ni and Cr might come from parent soil material. According to an ecological risk analysis of metals based on the ecological index suggested by Hakanson, the four types of land can be ranked by severity of ecological risk as follows: arable land > woodland > bare land > orchard land, with a high ecological risk of Cd for all four types. Management measures for land use planners for avoiding water, soil, and sediment pollution caused by metals around the Guanting Reservoir are presented.     

Assessing heavy-metal contamination and sources by GIS-based approach and multivariate analysis of urban–rural topsoils in Wuhan,central China

Nine potentially harmful heavy metals (Cd, Co, Cr, Cu, Hg, Mn, Pb, Ni, and Zn) were measured in 477 topsoil samples collected from urban–rural areas in the city of Wuhan in order to identify their concentrations and possible sources, and characterize their spatial variability for risk assessment. Results showed that in most rural areas heavy-metal concentrations in soil were similar to their natural background values, but Cd, Cu, Hg, Pb, and Zn concentrations were relatively higher in densely populated districts and around industrial facilities. Multivariate analyses (correlation matrix, principal component analysis, and cluster analysis) indicated that Cd, Cu, Hg, Pb, and Zn were mainly derived from anthropogenic inputs, and Co, Cr, and Mn were controlled by natural source, whereas Ni appeared to be affected by both anthropogenic and natural sources. The result of risk assessment indicated that nearly 48% of the study area suffered from moderate to severe contamination.     

莲花山矿区土壤-农作物系统中重金属调控

以广东省莲花山钨矿区耕地为研究点,研究土壤金属含量分布、形态特征及其调控措施。分析耕地土壤中Zn、Cu、Mn、Ni、Pb、Cd、As含量特征,以碱石灰、MnO2、Fe2O3和钙镁磷肥作为改良剂,对矿区污染耕地土壤进行改良,并种植萝卜Raphanus sativus,分析各改良剂对土壤金属形态及其在土壤-农作物界面迁移的影响。研究表明,矿区耕地土壤酸化, Zn、Mn、Pb、Cd和As超过土壤背景值,其中Cd和As污染严重,分别超过背景值的10.2-16.7倍和1.1-1.3倍。碱石灰有效降低耕地土壤pH值,降低土壤Zn、Cu、Mn、Ni、Pb、Cd可溶态含量,减少其在萝卜中积累。萝卜对Pb、Zn、Cd、Cu、Ni累积量与其可溶态含量相关性显著,与总量相关性不显著。Fe2O3、MnO2、钙镁磷肥对耕地土壤Zn、Cu、Ni、Mn、Pb、Cd 生物有效性及其在农作物中累积量无显著影响。矿区耕地土壤分别添加碱石灰、Fe2O3、MnO2,土壤中砷松散结合态含量降低,农作物砷累积量减少。钙镁磷肥对土壤砷形态无显著影响,但能显著降低萝卜中砷的累积量。碱石灰分别与Fe2O3、MnO2、钙镁磷肥相结合改良耕地土壤,比单一改良剂更能有效降低萝卜中砷的累积量。萝卜中砷累积量与松散结合态存在显著正相关性,与Ca-As存在显著负相关性。碱石灰分别和Fe2O3、钙镁磷肥同时加入土壤,能同时地有效降低Zn、Cu、Mn、Ni、Pb、Cd、As的有效性,及其在农作物累积量,因此,这2种改良方式是莲花山矿区土壤金属固定的有效措施。     

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。     

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.     

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.     

Current state of heavy metal contents in Vienna soils

This study presents the current state of heavy metal contents in both urban and forest soils within the city area of Vienna, Austria. Based on a systematic survey of urban soils and on targeted sampling in forest areas, local and regional anomaly thresholds are derived using statistical methods and considering regional distribution patterns. For urban soils, local anomaly thresholds of elements Cu (60?mg/kg), Hg (0.5?mg/kg), Pb (100?mg/kg) and Zn (200?mg/kg) exceed national guideline values for uncontaminated urban soils and according to Austrian legislation fall into the category “anthropogenic contamination present but no damage to plants, animals or humans detectable”. In forest soils within the city, thresholds are very similar to reference values for similar geological settings outside the city, apart from higher concentrations of elements Cr and Ni (threshold values of 107 and 64?mg/kg, respectively). Grouping urban soils according to land use reveals that Cd contents are 25?% higher, Pb contents 36?% higher, in traffic and industrial areas than in parks and like Cu, Hg and Zn, these elements can be shown to be at least partly caused by anthropogenic contamination. A dependency between heavy metal concentrations in soils and underlying geological units is shown within the flysch zone at the western city margin where the contents of elements Co, Cr, Cu, Ni and V are controlled by geology and reveal distinct differences between geological units. In built-up areas, no clear dependency between heavy metal contents in soils and geology is evident as urban soils represent accumulations by anthropogenic activity rather than in situ weathering products of underlying sediments.     

Heavy metals in top core sediments from the southern Campania shelf (Italy): Hints to define large-scale geochemical backgrounds

The results of a geochemical survey carried out on the southern Campania shelf (southern Italy) are illustrated, offering a tempting opportunity to discuss the statement and definition of regional geochemical backgrounds for selected heavy metals. A total of 104 top core sediments, collected on average 1.5 km from one another and covering a shelf area of about 1300 km², were analysed for grain size, organic carbon content (OC), and heavy-metal (As, Al, Fe, Cd, V, Cr, Zn, Cu, Ni, Hg, and Pb) concentrations. The characteristics of the area, scarcely influenced by industrial activities, and the extensive data set, make this study suitable for an appropriate multivariate and spatial geostatistical methodologies used for i) a reliable definition of large-scale marine sediments' geochemical backgrounds and ii) an accurate discrimination of different geological controls on trace-element distribution patterns. Enrichment factors estimated with respect to both the average shale composition and the weighted average metal concentrations measured in inland soils rule out significant anthropogenic inputs. A spatial-geostatistics approach (kriging of spatial component based on an accurate implementation of variographic surveying) was applied, and this is proposed as an appropriate quantitative methodology to define the geochemical backgrounds for the different heavy metals. Two nested spatial structures were identified for some of the heavy metals, thus allowing clear identification of local and regional geochemical controls related to the different spatial variability of grain size.     

Trace metals in the coastal soils developed from estuarine floodplain sediments in the Croatian Mediterranean region

Fertile soils in the River Neretva estuary were developed by fluvial sedimentation and deposition of the eroded soil material from the karst hills within the catchment. After extensive reclamation, two reclaimed land zones (fluvial terraces and lower-laying terraces) have been delineated, both used for agriculture. The main objectives of this study were to evaluate soil chemical and geochemical properties in reclaimed zones that differ mainly in topography, soil types and agricultural land use. The origin of the trace metals in the arable soils was studied using multivariate statistics, and interpolation maps of trace metals were produced using GIS and geostatistics. Soil trace metal concentrations do not exceed a threshold value established by the Croatian Government regulation, with exception of copper. Comparative analysis of the main soil properties and trace metal concentrations in the study area showed a pronounced spatial variation and differences between two reclaimed zones in soil organic matter content, bioavailable P and total concentrations of Cd and Cu. Factor analysis in the area of the lower-laying terraces showed grouping of bioavailable P and K, organic matter content and pH (negative loading) in the component associated mostly with the land use. In the area of the fluvial terraces, bioavailable P and total Cd were grouped in the same component that may be explained by the traditional small farm agriculture and overuse of mineral fertilizers. In the whole study area, processes of secondary salinization were determined, accompanied by the raised chloride and sodium concentration measured in the saturation soil extract.     

Heavy metal contamination of soils at old mining sites on Thasos Island,Greece

Thasos Island has a long history of metalliferous mining, the first mining activities having been initiated by the Phoenicians during the seventh century. The mineralogy of the mineralisation includes primary minerals (galena, sphalerite) and secondary oxidised minerals (smithsonite, cerussite). In the soils studied only secondary minerals were found. Clay minerals (kaolinite, illite, montmorillonite, mixed layer clays), plagioclase, calcite and dolomite are also present in the soils. Contamination derived from the old mining sites results in extremely high levels of Pb, Zn, Mn, Fe, As, Sb, Ag, Cd in soils in the vicinity of the old workings. Since many of the Thasos mining sites are in, or adjacent to, areas of agricultural land, plants growing on the polluted sous have increased concentrations of heavy metals. This may well have a possible effect on livestock.     

Compositional analysis of topsoil metals and its associations with cancer mortality using spatial misaligned data

The presence of toxic metals in soil per se, and in soil impacted by mining, industry, agriculture and urbanisation in particular, is a major concern for both human health and ecotoxicology. The dual aim of this study was: to ascertain whether topsoil composition could influence the spatial distribution of mortality due to different types of cancer and to identify possible errors committed by epidemiological studies which analyse soil composition data as a closed number system. We conducted an ecological cancer mortality study, covering 861,440 cancer deaths (27 cancer sites) in 7917 Spanish mainland towns, from 1999 to 2008. Topsoil levels of Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined by ICP-MS at 13,317 sampling points. We transformed the topsoil data in two ways, i.e. log transformation and centred logratio transformation. Principal factor analysis was performed to obtain independent latent factors for the transformed variables. To estimate the effect on mortality of topsoil factor loadings, we fitted Besag, York and Mollié models embedded in geostatistical-spatial models. This model included soil sample locations and town centroids (non-aligned data), fitted using the integrated nested Laplace approximation (INLA) as a tool for Bayesian inference and stochastic partial differential equations (SPDE). All results were adjusted for socio-demographic variables. The results indicated that soil composition could have an influence on the spatial distribution and mortality patterns of cancer. The analysis adjusted for socio-demographic variables showed excess male mortality due to digestive system tumours in areas with soils containing higher Cd, Pb, Zn, Mn and Cu concentrations, bladder cancer in areas with soils containing higher Cd concentrations, and brain cancer in areas with soils containing As. In both sexes, cancer of oesophagus was associated with soils containing a higher lead content, while lung cancer was associated with soils containing a higher copper content. Stress should be laid on the importance of taking into account the compositional nature of the data in this type of analysis.     

莱州湾表层沉积物中重金属时空分布、污染来源及风险评价

运用污染风险评价标准和方法研究了2010年5月(春)、8月(夏)、10月(秋)和12月(冬)莱州湾表层沉积物中7种重金属污染物的时空分布特征、来源及生态风险。结果表明,表层沉积物中Cr、Zn和Pb含量均呈现春季低于其他季节特征,秋季Hg含量是其他季节的4倍,Cu、As和Pb含量无显著季节差异。表层沉积物中Cr、Cu、Zn、As和Cd最高值出现在莱州湾中部及小清河河口等西部水域,来源呈现受自然作用影响较大的特征;而Hg和Pb最高值出现在龙口和界河河口等东部水域,来源呈现受周边工业污染物的人为排放影响较大的特征。基于地理累积指数、生态效应浓度以及Hakanson潜在生态风险指数的综合评价表明,13%~29%的研究区域的表层沉积物受到轻微程度的Cd、Hg和Pb污染,Cd和Hg高值水域达到中等生态风险程度;Hg和As在65%~68%的研究区域的表层沉积物中达到可能对沉积物底质环境及生物群落产生不利生态影响水平。基于对重金属污染物的评价结果,莱州湾表层沉积物质量较好,局部区域存在Hg、Pb、Cd和As的潜在污染风险。     

Anthropogenic metal pollution in surface sediments of the Tambaraparni River Estuary

Estuarine sediments in the<63 μm size fraction were collected from 15 stations within the Tambaraparni River Estuary, located on the east coast of India. The distribution of the heavy metals Cd, Co, Cr, Cu, Ni, Pb and Zn was recorded. Our analysis distinguished two groups of elements. First, Cd, Pb and Zn, which occurred in higher than expected concentrations indicative of pollution, and second, Co, Cr, Cu and Ni, which occurred at background levels. The highest metal concentration found in the study area was for Zn (1200 μ g·g^?1), and the lowest was for Cd (0.42 μ g·g^?1). It is presumed that river run-off, industrial waters and untreated domestic waters are major contributors to heavy metal pollution in the Tambaraparni River Estuary. The concentrations of heavy metal species in surface sediments (<2 m water depth) of the Tambaraparni Estuary were studied to determine the extent of anthropogenic inputs from catchment areas and to understand anthropogenic effects on geochemical process in this tropical estuarine system.     

Trace element content in soils of the King George and Elephant islands,maritime Antarctica

Trace element concentrations were studied in soils of the King George and Elephant islands in the maritime part of West Antarctica. The lowest concentrations of Cu, Pb, Cd, Zn, Ni and Mn were typical for the pristine soil of Elephant Island. The highest concentrations of these elements were found in the Fildes Peninsula and revealed the influence of human activities in the area of the Bellingshausen station and adjacent waste disposal sites. Ornithogenic soils of the Fildes Peninsula have shown low concentrations of Cd and As. Using geoaccumulation indexes, all the pristine soils of King George and Elephant islands and ornithogenic soils of the Fildes Peninsula were classified as unpolluted; the human-affected soils were mainly identified as moderately polluted. Obtained data can be used as background concentration levels for further researches.     

Geochemical anomalies in two sulfide-bearing waste disposal areas: Fe,Cu, Zn,Cd, Pb,and As in contaminated waters and snow,Kemerovo and Chelyabinsk regions,Russia

Sulfide-bearing mill wastes are sources of high concentrations of acid, soluble metals, Sb, and As. Contents of Cu, Zn, Fe, Pb, Cd, As, and Sb in wastes of the Belovo Zn-processing and the Karabash mineral-processing plants (Russia) exceed the average content in the upper continental crust and background soils. High-dissolved metal and As concentrations are found in acid drainages, which form as a result of interaction between sulfide wastes and water. Monitoring research using geochemical and geophysical methods was performed to evaluate the contamination of the surrounding area (water and bottom sediments in the contaminated rivers and snow cover). Zones of geochemical anomalies were identified where the concentrations of Fe, Cu, Zn, Cd, Pb, and As are 2–3 orders of magnitude higher than in drinking water standards (for rivers) and background levels (for snow). The use of geophysical methods allowed us to prove penetration of drainage solutions into the groundwaters. The total environmental damage caused by the pollution of water and land resources in the Belovo Zn-processing plant waste disposal area amounted to $156 million at the time of 2011, and could reach $480 million by 2030, if steps are not taken in recycling and remediation of disturbed areas.     

Mapping Soil Lead and Remediation Needs in Contaminated Soils

For the past two decades, the Taiwan Environmental Protection Administration has made a systematic investigation of As, Cd, Cr, Cu, Pb, Hg, Ni and Zn in agricultural soils to identify soil pollution from industrial production. The EPA has cooperated with local governmental agencies to establish a soil quality monitoring system that would upgrade the land recovery ability and prohibit polluted lands from being cultivated or turned over to other uses. Based on an island-wide soil survey, more than 1,000 hectares of arable soils in Taiwan were found to be considerably contaminated by heavy metals. One of the heavy metal contaminated sites, located near a ceramic product manufacturing factory in Nantou County, was identified as lead contaminated. According to the Nantou Environmental Protection Bureau, the lead content in contaminated sites showed a great variation of several mg Pbkg^–1 soil to several thousands mg Pbkg^–1 soil. Therefore, it is appropriate to estimate the lead spatial distribution through geostatistics such as Kriging. The soil lead concentration contour maps obtained by Kriging can help us to identify the pollution patterns and delineate the range of contaminated sites. The purpose of this study is to determine the Pb concentrations at each location by performing detailed soil sampling on those Pb contaminated sites and estimating the lead spatial distributions by Kriging. A total of 70 soils were sampled from different locations at two experiment sites. Lead contents were determined with 0.1M HCl extractable lead content of the soils. The results obtained by investigating the lead contents in each 15cm segment down to a 60cm depth, revealed that lead contents were greater in arable land near the ceramic products manufacturing factory, and lead concentrations decreased with depth. In addition, Pb concentrations in heavily contaminated soils showed heavy concentrations of Pb in specific locations. Results from Pb content spatial distributions indicated that the Kriging model is a useful tool and can provide decision-makers with critical information for delineating hazardous areas in heavy metal contaminated sites.     

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.     

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.     

Factors affecting HCH and DDT in soils around watersheds of Beijing reservoirs,China

The factors that influence the dynamics of hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) in soils around the watersheds of Beijing reservoirs were examined. Compared with other studies on HCH and DDT in soils and established reference values, the concentrations of HCH and DDT in soils around our study area were relatively low. The relationships between HCH and DDT concentrations and land use, soil texture, and soil properties were discussed. HCH and DDT concentrations were higher in arable soils than those in uncultivated fallow soils. Although land use was the most important factor affecting HCH and DDT residues, additional factors such as soil texture and soil total organic carbon were also involved in pesticide retention in soils. The results indicated that the historical agricultural applications of HCH and DDT were the major source of their residues. Atmospheric deposition, as well as long-distance transportation and inputs from surrounding weathered agricultural soils may also serve as important sources of HCH and DDT residues in the watersheds.     

工业城市不同功能区土壤和蔬菜中重金属污染及其健康风险评价

为了研究和评价工业城市不同功能区的土壤和蔬菜中重金属污染和健康风险状况,以株洲市为例,在工业区（石峰区）、农业区（芦淞区）和旅游区（大京风景区）分别采集土壤和蔬菜样品,分析重金属Cd、As、Pb、Hg、Zn、Cr和Cu的质量分数,并采用地质累积指数法（Igeo）和健康风险评价模型分别对土壤和蔬菜中重金属进行评价。结果表明：工业区、农业区和旅游区土壤中Cd、As、Pb、Hg、Zn、Cr和Cu的平均质量分数都超出湖南省土壤背景值,部分重金属甚至超出国家土壤环境质量二级标准。不同功能区土壤中重金属的地质累积指数（Igeo）表明：工业区、农业区和旅游区土壤受到不同程度的重金属污染,其中Cd和Hg的污染最为严重,污染程度依次是工业区〉农业区〉旅游区。不同功能区蔬菜中Cd、As、Pb和Zn的危害商（HQ）值都大于1.0,而Cu和Cr的危害商（HQ）都小于1.0。不同功能区蔬菜中重金属危害指数（HI）都大于10.0,尤其是工业区蔬菜的危害指数（HI）〉100.0,当地成年人食用受到重金属污染的蔬菜会导致严重的健康危害,其中Cd和As,是危害指数（HI）的主要贡献者,两者贡献率之和的范围为75%~89%,而Cr的贡献率几乎为0。