Assessment of heavy metal concentrations and associated resistant bacterial communities in bulk and rhizosphere soil of <Emphasis Type="Italic">Avicennia marina</Emphasis> of Pichavaram mangrove,India

Heavy metals are known to pose a potential threat to terrestrial and aquatic flora and fauna. Due to increasing human influence, heavy metal concentrations are rising in many mangrove ecosystems. Therefore, an assessment of heavy metal (Cd, Cr, Cu, Ni, Pb, Fe, Mn, and Zn) concentrations was conducted within the bulk soil and rhizosphere soil of Avicennia marina at the Pichavaram Mangrove Forest in India. The rhizosphere soil showed higher concentrations of metals than the bulk soil. Compared to the bulk soil, the metals Cd, Fe, Mn, and Zn were 6.0–16.7% higher, whereas Cr, Cu, Ni, and Pb were 1.7–2.8% higher concentration. Among the three selected sampling sites (dense mangrove forest, estuarine region, and sea region), the sea region had the highest concentration of all heavy metals except Zn. The trend of the mean metal concentration was Fe > Mn > Cr > Ni > Cu > Pb > Zn > Cd. Heavy metals concentrations elevated by the 2004 tsunami were persistent even after 4 years, due to sedimentary soil processes, the rhizosphere effect of mangroves, and anthropogenic deposition. Analysis of the heavy metal-resistant bacteria showed highest bacterial count for Cr-resistant bacteria and rhizosphere soil. The maximum level of heavy metal-resistant bacteria was observed at the site with the highest heavy metal contamination. The heavy metal-resistant bacteria can be used as indicator of heavy metal pollution and furthermore in bioremediation.     

Assessment of spatial distribution and possible sources of heavy metals in the soils of Sariseki-Dörtyol District in Hatay Province (Turkey)

In this study, total heavy metal content of soil and their spatial distribution in Sar?seki-Dörtyol district were analyzed and mapped. Variable distance grids (0.5, 1.0 and 2.0 km) were established, with a total of 102 soil samples collected from two different soil depths (0–5 and 5–20 cm) at intersections of the grids (51 sampling point). Soil samples were analyzed for heavy metals (Cd, Co, Cr, Cu, Pb, Zn, Mn, Fe, and Ni). The most proper variogram models for the contents of all heavy metal were spherical and exponential ones. The ranges of semivariograms were between 1.9 and 31.1 km. According to the calculated geoaccumulation (I _geo) values, samples from both soil depths were classified as partly to highly polluted with Cd and Ni and partly polluted with Cr and as partly polluted-to-not polluted with Pb and not polluted with Cu, Fe and Mn. Similar results were also obtained when evaluated by the enrichment factor. The contamination levels of the heavy metals were Ni > Cd > Cr > Pb > Zn > Cu > Co > Fe > Mn in decreasing order. The soils in the study area are contaminated predominantly by Cd and Ni, which may give rise to various health hazards or diseases. Cadmium pollution results primarily from industrial activities and, to a lesser extent, from vehicular traffic, whereas Ni contents in the study area result from parent material, phosphorus fertilizer, industries, and vehicles.     

Multivariate statistical approach to identify heavy metal sources in agricultural soil around an abandoned Pb–Zn mine in Guangxi Zhuang Autonomous Region, China

A study of agricultural lands around an abandoned Pb–Zn mine in a karst region was undertaken to (1) assess the distribution of heavy metals in the agricultural environment, in both dry land and paddy field; (2) discriminate between natural and anthropogenic contributions; and (3) identify possible sources of any pollution discovered. Ninety-two samples of cultivated soils were collected around the mine and analyzed for eight heavy metals, pH, fluoride (F^?), cation exchange capacity, organic matter, and grain size. The eight heavy metals included Cd, Cr, Cu, Ni, Pb, Zn, As, and Hg. The average concentrations (mg/kg) obtained were as follows: Cd 16.76 ± 24.49, Cr 151.5 ± 18.24, Cu 54.28 ± 18.99, Ni 57.5 ± 14.43, Pb 2,576.2 ± 1,096, Zn 548.7 ± 4,112, As 29.1 ± 6.36, and Hg 1.586 ± 1.46. In a site where no impact from mining activities was detected, the mean and median of Cd, Cu, Ni, Pb, Zn, As, and Hg concentrations in investigated topsoils were higher than the mean and median of heavy metal concentrations in reference soils. An ensemble of basic and multivariate statistical analyses was performed to reduce the multidimensional space of variables and samples. Two main sets of heavy metals were revealed as indicators of natural and anthropogenic influences. The results of principal component analysis (PCA) and categorical PCA demonstrated that Cd, Cu, Pb, Zn, and Hg are indicators of anthropogenic pollution, whereas Cr, As and Ni concentrations are mainly associated with natural sources in the environment. The contamination from Pb–Zn mining operations, coupled with the special karst environment, was a key contributing factor to the spatial distribution of the eight heavy metals in the surrounding soil. The values of heavy metals in the soil samples suggested the necessity of conducting a rigorous assessment of the health and environmental risks posed by these residues and taking suitable remedial action as necessary.     

Assessment of heavy metal contamination levels of street dust in the city of Lublin,E Poland

Heavy metals are constantly emitted into the environment and pose a major threat to human health, particularly in urban areas. The threat is linked to the presence of Cd, Cr, Cu, Ni, Pb, and Zn in street dust, which consists of mineral and organic particles originating from the soil, industrial emitters, motor vehicles, and fuel consumption. The study objective was to determine the level of street dust contamination with trace metals in Lublin and to indicate their potential sources of origin. The analyses were carried out with an energy-dispersive X-ray fluorescence spectrometer. The sampling sites (49) were located within the city streets characterised by varying intensity of motor traffic. The following mean content values and their variation (SD) were determined: Cd: 5.1?±?1.7 mg kg^?1, Cr: 86.4?±?23.3 mg kg^?1, Cu: 81.6?±?69.2 mg kg^?1, Ni: 16.5?±?3.9 mg kg^?1, Pb: 44.1?±?16.4 mg kg^?1, and Zn: 241.1?±?94.6 mg kg^?1. The level of pollution was assessed with several widely used geochemical indices (geoaccumulation index, enrichment factor, pollution index, index of ecological risk, and potential ecological risk index). For most of the indices, the mean (median) values are arranged in the following manner: Zn?>?Cu(or Cd)?>?Pb?>?Ni?>?Cr. In general, street dust in Lublin does not show pollution with Cr, Ni, and Pb. I_geo and EF indices show moderate levels for Cu, Cd, and Zn; their presence in street dust is linked with anthropogenic factors (motor traffic). A significant threat is posed by Cd, and more than half of the samples show considerable pollution with cadmium (median for the index of ecological risk: 151). The spatial pattern of indices and the results of statistical analyses (CA, PCA) indicate three groups of elements: (1) Cr and Ni: natural origin; (2) Pb: mixed origin; and (3) Cd, Cu, and Zn: anthropogenic origin (mainly motor vehicle traffic). Higher content values for metals of anthropogenic origin in street dust indicate that it is a source of pollution of soil and air in the city.     

Spatio-temporal dynamics of heavy metals in sediments of the river estuarine system: Mahanadi basin (India)

Dynamics of heavy metals in the surface sediments of Mahanadi river estuarine system were studied for three different seasons. This study demonstrates that the relative abundance of these metals follows in the order of Fe > Mn > Zn > Pb > Cr > Ni ≥ Co > Cu > Cd. The spatial pattern of heavy metals supported by enrichment ratio data, suggests their anthropogenic sources possibly from various industrial wastes and municipal wastes as well as agricultural runoff. The metal concentrations in estuarine sediments are relatively higher than in the river due to adsorption/accumulation of metals on sediments during saline mixing, while there is a decreasing trend of heavy metal concentrations towards the marine side. The temporal variations for metals, such as Fe, Mn, Zn, Ni and Pb exhibit higher values during monsoon season, which are related to agricultural runoff. Higher elemental concentrations are observed during pre-monsoon season for these above metals (except Ni) at the polluted stations and for metals, such as Cr, Co and Cd at all sites, which demonstrate the intensity of anthropogenic contribution. R-mode factor analysis reveals that “Fe–Mn oxy hydroxide”, “organic matter”, “CaCO₃”, and “textural variables” factors are the major controlling geochemical factors for the enrichment of heavy metals in river estuarine sediment and their seasonal variations, though their intensities were different for different seasons. The relationships among the stations are highlighted by cluster analysis, represented in dendrograms to categorize different contributing sites for the enrichment of heavy metals in the river estuarine system.     

Distribution and speciation of heavy metals in surface sediments from the Yangtze estuary and coastal areas

The concentrations and speciation of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in the sediments of the nearshore area, river channel and coastal zones of the Yangtze estuary, China, were systematically investigated in this study. The concentrations of all heavy metals except Ni in the sediments of the nearshore area were higher than those of the river channel and coastal zones. In the nearshore area, the concentrations of most heavy metals except Hg in the sediments of the southern branch were higher than those of the northern branch because of the import of pollutants from the urban and industrial activities around. When compared with the threshold effect level (TEL) and geochemical background levels, Cr, Ni and As accumulated and posed potential adverse biological effects. The speciation analysis suggested that Cd, Pb and Zn in the sediments of the three zones showed higher bioavailability than the other heavy metals, and thus posed ecological risk. Significant correlations were observed among Cr, Cu, Ni and Zn (r > 0.77) in the nearshore area, Ni, Cu, Zn and Pb (r > 0.85) in the river channel and Ni, Cu, Cr, Pb and Zn (r > 0.75) in the coastal zone. Principal component analysis (PCA) indicated that the discharge of unban and industrial sewage, shipping pollution and the properties of the sediments (contents of Fe, Mn, Al, TOC, clay and silt) dominated the distribution of heavy metal in the nearshore area, river channel and coastal zones of the Yangtze estuary.     

Contamination assessment and health risk of heavy metals in dust from Changqing industrial park of Baoji,NW China

The contents of Co, Cr, Cu, Mn, Ni, Pb and Zn in the dust samples collected from Changqing industrial park of Baoji city, NW China, were measured by XRF, while As and Hg in the dust samples were analyzed by AFS. Geo-accumulation index (I _geo), pollution index (PI) and integrated pollution index (IPI) were calculated to evaluate the heavy metal contamination level of dust. The health risk due to exposure to heavy metals in dust was analyzed by the Health Risk Assessment Model of US EPA. The results show that the arithmetic means of As, Co, Cr, Cu, Hg, Mn, Ni, Pb and Zn are 23.3, 16.4, 1591.8, 178.2, 0.243, 346.5, 40.2, 1,586.2 and 1,918.8 mg kg^?1, respectively, which are higher than the background values of Shaanxi soil, especially for Cr, Cu, Hg, Pb, and Zn. The mean values of I _geo reveal the order of Pb > Zn > Cr > Hg > Cu > As > Co > Ni > Mn. The high I _geo of Cr, Cu, Hg, Pb and Zn in dust indicates that there is considerable pollution from Cr, Cu, Hg, Pb and Zn, while the low I _geo of As, Co, Mn and Ni presents no pollution in dust. The assessment results of PI support the results of I _geo, and IPI indicates heavy metals in dust polluted seriously. The health risk assessment shows that ingestion of dust particles is the route for exposure to heavy metals from dust, followed by dermal adsorption. Exposure to As, Cr and Pb from dust may pose a potential health threat to children and adults. The risk of cancer from As, Co, Cr and Ni due to dust exposure is low.     

南宁市郊周边农田土壤-农作物系统重金属元素迁移特征及其影响因素

通过采集南宁市郊农田中玉米、蔬菜、水稻可食部分及其根系土150组,研究重金属元素在不同土壤-农作物系统中迁移特征及其影响因素,结果表明:根系土中Hg、Cd、Cr、Cu、Ni、Pb、Zn平均含量分别为0.116、0.202、56.76、22.12、14.49、25.18和56.28 mg·kg-1。农作物对应平均含量分别为0.001 1、0.037、0.054、1.153、0.205、0.011和9.37 mg·kg-1。根系土富集因子表明Cd受到不同程度人为活动影响,Cr和Ni主要受地质背景控制;不同作物系统元素富集因子表明Pb在土壤-农作物系统中迁移能力最低,Zn迁移能力最强。Cd、Cr、Cu、Ni、Pb和Zn在土壤-水稻系统重迁移能力显著高于蔬菜和玉米。根系土中pH、CaO、有机质、Fe2O3、K2O、MgO与重金生物富集系数呈显著性负相关,但在土壤-叶类蔬菜系统中根系土中K2O、MgO与Hg生物富集系数呈显著正相关。      

Heavy metal exposure from co-processing of hazardous wastes for cement production and associated human risk assessment

This study was carried out to determine the concentration of heavy metals (Cd, Ni, Pb, Cr, Ni and Zn) in ordinary Portland cement (OPC) produced from the co-processing with hazardous waste in comparison with OPC produced using natural raw materials. The results showed that the concentration of heavy metals in cement produced from natural raw material was in the order of Zn > Pb > Cr > Ni > Cu > Cd. Zn and Cd were the highest and the lowest concentrations, respectively, in cements produced from the co-processing activity. The difference between heavy metals concentrations in OPC produced with and without co-processing was found to be statistically significant. The concentration of heavy metals in the cement produced is generally factory dependent. The human risk assessment associated with the heavy metals for non-carcinogenic and carcinogenic risks has been evaluated. The calculated hazard index (HI) and total lifetime cancer risks (LCR) were lower than the acceptable threshold reference values, HI < 1 and LCR < 1 × 10^?4, respectively. Thus, it is anticipated that there is no potential of non-carcinogenic and carcinogenic risks for both adult and children. However, the findings indicated that there is a need for regulatory monitoring. The exposure pathway for both non-carcinogenic and carcinogenic risks are both in the order of ingestion > dermal > inhalation.     

Comparison of different methods for assessing heavy metal contamination in street dust of Xianyang City, NW China

Street dust is one of the important indicators that reflect the status of urban environmental pollution. There are many studies of heavy metals contamination of street dust in capital cities; however, little attention has been paid to this kind of study in medium cities, including China. The dust samples were collected in the district of traffic crossroads in Xianyang city, Shaanxi Province. Pb, Cd, Cu, Ni, Zn, Cr and Mn concentrations were determined using atomic absorption spectrometry (AAS). The results indicate that the concentrations of heavy metals are higher than the background values of soils in Shaanxi Province. The contamination level of heavy metals is assessed by potential ecological risk index (E _r), geoaccumulation index (I _geo), enrichment factor (EF) and pollution index (Pi). The low I _geo, EF, E _r, Pi and PI_n (integrated pollution index) for Mn in street dusts indicate an absence of distinct Mn pollution. The high EF, Pi and PI_n of Cu and Zn indicate that there is considerable Cu and Zn pollution. It is suggested that more attention should be paid to heavy metals contamination of Cu and Zn. The assessment results of Pi and PI_n suggest that Pb, Ni and Cr present strong pollution; however, their EFs indicate that they cause moderate pollution and their I _geo indicates that they are unpolluted to moderately polluted. The contamination class value with different assessing methods is of the order: Pi ≈ PI_n > EF > I _geo > E _r.     

Bioaccumulation of heavy metals in organs of fresh water fish Cyprinus carpio (Common carp)

The objective of the present study is to determine the bioaccumulation of heavy metals in various organs of the fresh water fish exposed to heavy metal contaminated water system. The experimental fish was exposed to Cr, Ni, Cd and Pb at sublethal concentrations for periods of 32 days. The elements Cd, Pb, Ni and Cr were assayed using Shimadzu AA 6200 atomic absorption spectrophotometery and the results were given as μ/g dry wt. The accumulation of heavy metal gradually increases in liver during the heavy metal exposure period. All the results were statistically significant at p < 0.001. The order of heavy metal accumulation in the gills and liver was Cd > Pb > Ni > Cr and Pb > Cd > Ni > Cr. Similarly, in case of kidney and flesh tissues, the order was Pb > Cd > Cr > Ni and Pb > Cr > Cd > Ni. In all heavy metals, the bioaccumulation of lead and cadmium proportion was significantly increased in the tissues of Cyprinus carpio (Common carp).     

Contamination and ecological risk assessment of heavy metals in street dust of Tehran,Iran

Heavy metals are introduced in human tissue through breathing air, food chain and human skin. They can cause damage to the nervous system and internal organs. In the present study, sixty street dust samples were collected from the central area of Tehran and were digested in the laboratory to determine the content of Zn, Ni, Cd, Cr, Cu and Pb, using inductively coupled plasma optical emission spectrometry (ICP-OES). The level of contamination with the analyzed metals was determined according to the following indices: geo-accumulation index (I _geo), enrichment factor (EF), pollution index (PI), integrated pollution index (IPI) and potential ecological risk index (RI). The average concentration of heavy metals found was in the order of Zn > Cu > Pb > Ni > Cr > Cd. The average I _geo values for Cd, Cr, Cu, Ni, Pb and Zn were 1.53, ?1.88, 2.68, ?0.67, 1.62 and 2.70, respectively. Among the investigated heavy metals, zinc and copper had the maximum average EF values and were placed into the “very severe enrichment” class. Potential ecological risk factor (E _r) also indicated that Cd had the highest risk, and it was classified as of considerable potential ecological risk. Therefore, it is necessary to pay more attention to the appearance of Cd in the human environment. The calculated potential ecological risk index values also illustrated that the street dust samples presented a “moderate ecological risk.” The calculated IPI values showed that the pollution levels of the street dust samples ranged from high to extremely high.     

固体聚合膜电解浓集法测量天然水中低含量氚的化学淬灭效应研究

固体聚合膜电解浓集法是浓缩氚含量较低(1 Bq/m~3)的天然水样的常用方法,但因水样自身含有杂质离子或电解装置聚合膜带入杂质进入浓集液,使浓集液偏酸性,在测量过程中易产生化学淬灭效应,导致氚的测量值偏低。本文研究了水样自身存在的杂质离子和聚合膜上残留的杂质离子、样品溶液的pH值及其电导率所产生的化学淬灭效应的影响,实验表明,为减少化学淬灭效应,提高测量低含量氚的准确性,需保证水样溶液呈中性,电导率≤1μS/cm,同时避免杂质沉积在聚合膜上。如果水样溶液的pH值偏酸性、电导率大于1μS/cm,可采用酸碱混合型离子交换树脂去除水样中自身的杂质;对于聚合膜引入的杂质,可在电解后的水样中加入微量氨水将其pH值调节至中性。     

甘肃嘉峪关市表层土壤重金属空间分布与评价

为研究嘉峪关市重金属分布对环境的影响,分析了嘉峪关市表层土壤重金属分布和含量变化,并评价其富集程度,判断其来源和影响因素。采用电感耦合等离子体质谱仪（ICP-MS）测量嘉峪关市134个表层土壤样品中六种重金属元素（Cr、Cd、Cu、Pb、Ni、Zn）的含量,其平均含量分别为281.6 mg/kg、0.35 mg/kg、60.68 mg/kg、51.39 mg/kg、108.65 mg/kg、161.0 mg/kg。在土壤重金属含量空间分布的基础上,用内梅罗指数法和地累积指数法对研究区土壤重金属富集程度进行了评价,六种元素地累积指数排序依次为: Cr > Cd > Pb > Cu > Zn > Ni,各功能区重金属元素整体富集程度依次为工业区 > 戈壁 > 生活区 > 农业区。戈壁采样点重金属元素含量（除Ni外）高于农业区,除工业因素外,地表植被的缺失加剧了戈壁地区重金属元素的富集。结合主成分分析,重金属元素空间展布,及内梅罗指数评价和地累积指数评价,分析了各元素可能的来源,认为Cr、Zn主要来自以钢铁生产加工为主的工业源,Cd、Cu、Pb来自于交通源,Ni可能与钢铁生产或当地背景值有关。通过分析嘉峪关市土壤重金属分布情况,以期为改善当地土壤质量提供科学依据,为我国西北地区土壤重金属的研究提供参考。     

Quantitative spatial characteristics and environmental risk of toxic heavy metals in urban dusts of Shanghai,China

Associated with the rapid urbanization and industrialization, most of the urban parks and recreational areas in Shanghai are built close to major roads or industrial areas, where they are subject to many potential pollution source, including automobile exhaust and factory emissions. Urban dusts, containing many toxic heavy metals such as Pb, Cr, Cd, Hg and As, are one of main contributors for environmental pollution. In this study, 261 dust samples were collected from two different localities (streets and parks) in the urban area of Shanghai, China. Pb and Cr concentrations of all samples were determined by atomic adsorption spectrophotometer analyzer, and Cd, As and Hg concentrations in 74 samples by atomic fluorescence spectroscopy. The mean concentrations of Pb, Cr, Cd, As and Hg are 287, 157, 1.24, 8.73 and 0.16 mg kg⁻¹, respectively. Each heavy metal shows a wide range of concentration values. In comparison with heavy metal background values of soil in Shanghai, urban dusts have elevated metal concentrations as a whole, except those of As. The concentrations of Pb, Cr, Cd, As and Hg are 11.3, 2.1, 10.3, 0.997, 1.7 times of the soil background values, respectively. Compared with the global mean concentrations, Cr concentration in urban dusts is slightly higher. Pb, Cr and Hg show normal distribution after logarithmic transformation. Pb, Cr, Cd, As and Hg have second-order variation trends of the spatial distribution. The spatial distribution features of five toxic heavy metals, in general, illustrate relatively high levels within the regions of the inner-city ring highway and southwestern Shanghai. Cr and Cd are higher in Baoshan industrial park and the shipbuilding industries regions. The order of environmental risk is Pb > Cd > Cr > Hg > As. Pb and Cd have the highest risk for environment pollution and human health among the five metals. The pollutant sources of toxic heavy metals in Shanghai urban dusts are preliminarily concluded as follows: As may have mainly a natural source. Burning of coal has become the main source of Hg pollution. Pb, Cr and Cd have three sources, traffic, building construction, and weathering corrosion of building materials.     

An evaluation of heavy metal pollution within historic cultural strata at a specialized salt production site at Zhongba in the Three Gorges Reservoir region of the Yangtze River, China

The concentrations of Hg, Cu, Pb, Cr, and Ni in soil samples collected from a specialized salt production site at Zhongba in the Three Gorges Reservoir region of the Yangtze River in China were analyzed to reconstruct the heavy metal contamination contexts of different historic periods over the last 4,500 years. The results show that the observed sequence for individual levels of heavy metal pollution was as follows: Hg > Cu > Ni > Pb ≈ Cr. Hg pollution was high during every time period except the Ming Dynasty, with peaks being observed from the Spring and Autumn period. The pollution of Cu and Ni peaked during the Xi Zhou and Xia Dynasties, respectively. The pollution level of Pb has gradually increased since the Qin Dynasty and has coincided with the use of leaded gasoline. Cr contamination was moderate in all soil strata with little indication of change. Comprehensive heavy metal contamination was high during all of these periods, except during the Ming Dynasty, with peaks being observed between the Spring and Autumn Period and throughout the Warring States Period. Enrichment factors (EFs) were used to obtain information on heavy metal sources. The EFs indicate that most of the Hg and Cu originated from human activities, whereas Pb, Cr, and Ni predominantly came from crust weathering. Several preliminary inferences regarding the development of heavy metal utilization in the area were generated. Cu usage had developed well during the Xi Zhou Dynasty and the Autumn Period. Hg usage emerged during the Xia Dynasty and matured between the Spring and Autumn Period and the Warring States Period. Ni usage conceivably started during the Xia Dynasty. Other factors, such as religious activities, technology, environmental awareness and the intensity of salt production, have also affected heavy metal pollution concentrations.     

Serpentine geology links to water quality and heavy metals in sediments of a stream system in central Queensland,Australia

Serpentinite soils, common throughout the world, are characterized by low calcium-to-magnesium ratios, low nutrient levels and elevated levels of heavy metals. Yet the water quality and heavy metal concentrations in sediments of streams draining serpentine geology have been little studied. The aim of this work was to collect baseline data on the water quality (for both wet and dry seasons) and metals in sediments at 11 sites on the Marlborough Creek system, which drains serpentine soils in coastal central Queensland, Australia. Water quality of the system was characterized by extremely hard waters (555–698 mg/L as CaCO₃), high dissolved salts (684–1285 mg/L), pH (8.3–9.1) and dissolved oxygen (often >110% saturation). Cationic dominance was Mg > Na > Ca > K and for anions HCO₃ > Cl > SO₄. Al, Cu and Zn in stream waters were naturally high and exceeded Australian and New Zealand Environment and Conservation Council guidelines. Conductivity displayed the highest seasonal variability, decreasing significantly after wet season flows. There was little seasonal variation in pH, which often exceeded regional guidelines. Stream sediments were enriched with concentrations of Ni, Cr, Co and Zn up to 35, 21, 10 and 2 times the world average for shallow sediments, respectively. Concentrations for Ni and Cr were up to 60 and 16 times those of the relevant Interim Sediment Quality Guidelines Low Trigger Values, respectively. The distinctive nature of the water and sediment data suggests that it would be appropriate to establish more localized water quality and sediment guidelines for the creek system for the water quality parameters conductivity, Cu and Zn (and possibly Cr and Cd also), and for sediment concentrations of Cd, Cr and Ni.     

Environment impact of heavy metals on urban soil in the vicinity of industrial area of Baoji city,P.R. China

Heavy metals in soils are of great environmental concern, in order to evaluate heavy metal contents and their relationships in the surface soil of industrial area of Baoji city, and also to investigate their influence on the soils. Soil samples were collected from 50 sites, and the concentration of Pb, Zn, Cu, Cr, Ni heavy metals and the contents of characteristics in soil from industrial area of Baoji city were determined with X-ray fluorescence method. The concentrations of Pb, Zn, Cu, Cr and Ni in the investigated soils reached the amount of 2,682.00–76,979.42, 169.30–8,288.58, 62.24–242.36, 91.96–110.54 and 36.14–179.28 mg kg⁻¹, respectively. The major element Pb contents of the topsoils were determined. to highlight the influence of ‘anthropic’ features on the heavy metal concentrations and their distributions. To compare, all values of elements were much higher than those of unpolluted soils in the middle of Shaanxi province that average 16.0–26.5, 67.1–120.0, 17.8–57.0, 46.9–65.6 and 24.7–34.6 mg kg⁻¹ for Pb, Zn, Cu, Cr and Ni, respectively. An ensemble of basic and relativity analysis was performed to reduce the precipitate of Pb in soil was extremely high and greatly relativity with other elements. Meanwhile, Pb, Zn, Cu, Cr, Ni heavy metals were typical elements of anthropic activities sources, so it was easy to infer to the tracers of anthropic pollutions from the factorial analysis, which was coming from the storage battery manufactory pollutions. The pollutant distributions were constructed for the urban area which identified storage battery manufactory soot precipitate as the main source of diffuse pollution and also showed the contribution of the topsoils of industrial area of Baoji city as the source point of pollution. Consequently, the impact of heavy metals on soil was proposed and discussed. These results highlight the need for instituting a systematic and continuous monitoring of heavy metals and other forms of pollutants in Baoji city to ensure that pollution does not become a serious problem in the future.     

A study on soil physico-chemical, microbial and metal content in Sukinda chromite mine of Odisha, India

Soil samples from chromite mining site and its adjacent overburden dumps and fallow land of Sukinda, Odisha, were analysed for their physico-chemical, microbial and metal contents. Chromite mine soils were heterogenous mixture of clay, mud, minerals and rocks. The pH of the soils ranges between 5.87 and 7.36. The nutrient contents of the mine soils (N, P, K and organic C) were found to be extremely low. Analysis of chromite mine soils revealed accumulation of a number of metals in high concentrations (Fe > Cr > Mn > Ni > Zn > Pb > Sr) which exceeded ecotoxicological limits in soil. Correlation and cluster analysis of metals revealed a strong relation between Cr, Ni, Fe, Mn among the different attributes studied. Assessment of different microbial groups such as fungi, actinomycetes and bacteria (heterotrophic, spore forming, free-living nitrogen fixing, phosphate solubilising and cellulose degrading) from mine soils were found to be either extremely low or absent in some soil samples. Further chromium tolerant bacteria (CTB) were isolated using 100 mg/L Cr(VI) enriched nutrient agar medium and were screened for their tolerance towards increasing concentrations of hexavalent chromium and other toxic metals. Out of 23 CTB isolates, three bacteria tolerated up to 900 mg/L, 6 up to 500 mg/L, 20 up to 200 mg/L of Cr(VI). These bacteria were also found to be sensitive towards Cu > Co > Cd and very few CTB strains could show multiple metal tolerance. These strains have great scope for their application in bioremediation of toxic chromium ions in presence of other metals ions, which needs to be explored for their biotechnological applications.     

The effect of mineralogy on the mobility of heavy metals in mine tailings: a case study in the Samsanjeil mine,Korea

This study examined the chemical speciation and mobility of As and heavy metals in a tailings impoundment in Samsanjeil mine located in Gosung, Korea, as well as the factors affecting them. XRD, SEM, and 5-step sequential extraction were used to examine the samples at two sampling sites (NN and SN sites). The pH of the tailings decreased with increasing depth at the NN site (from 7.2 to 2.8), whereas no significant differences were observed at the SN site (8.1–8.8). The samples at the SN site showed a larger amount of calcite than those at the NN site, indicating that calcite plays an important role buffering the pH in the study sites. Jarosite was found only at the lower part of the NN site, where calcite was not found. The mineralogical observation of jarosite and calcite was also confirmed by SEM. The concentrations of As and heavy metals in the tailings were as follows: Cu > As > Zn > > Pb > Co > Cr > Ni > Cd. The total concentrations of Ni, Zn, Co, and Cd were higher at the SN site than those at the NN site. On the other hand, the concentrations of As and Cr existing as oxyanions were higher at the NN site, which can be explained by the mobility changes of those elements affected by pH variations. At the NN site, the fractions of heavy metals bound to the Fe/Mn oxides, except for As and Cr, decreased, and Cu, Zn, and Co showed an increasing fraction of exchangeable metals with increasing depth. This suggests that the pH and resulting surface charge of minerals, such as goethite and jarosite, are the dominant factors controlling the chemical speciation of metals. These results highlight the importance of mineralogy in controlling the mobility and possible bioavailability of heavy metals in tailings.