Groundwater Contribution of Metals from an Abandoned Mine to The North Fork of The American Fork River, Utah

Surface water discharge measurements and metals concentrations in the North Fork of the American Fork River, Utah, its tributaries, and the groundwater in the vicinity of the Pacific Mine were used to evaluate the impact of groundwater on loading rates of metals and As to the river. Fish in the river contain As, Cd, and Pb at concentrations that are hazardous to human health if consumed. The results suggest that dissolved As, Cd, Cu, Fe, Mn, Pb, and Zn enter the river when it is a gaining stream. However, the suspended metals load is significantly greater than the dissolved load, and generally decreases through the reach of river adjacent to the mine site. Cadmium and Mn travel as dissolved species while Cu, Fe, Pb, and Zn travel as suspended solids. Arsenic seems to travel both with the suspended solids and in the dissolved state. The geochemical modeling program PHREEQC and a diffuse double layer surface complexation model were used to investigate the chemical controls on metals mobility and attenuation in the surface and groundwaters at the site. Based on the PHREEQC results, the most important process in these waters is the precipitation of ferrihydrite, also referred to as hydrous ferric oxide (HFO). Copper, Pb, most importantly Zn, and to a lesser degree As sorb to HFO.     

Dissolved and Particulate Metals in the Mero River (NW Spain): Factors affecting Concentrations and Load during Runoff Events

This article examines the metal [aluminum (Al), iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn)] runoff dynamics in the Mero River (northwestern Spain). At the catchment outlet, metal concentrations, suspended solids, dissolved organic carbon, pH, and discharge were determined during three runoff events. The river drains an agroforestry catchment of 65 km² with relatively high livestock density. Dissolved and particulate metal concentrations increased during the events with respect to pre-event concentrations, but the increase of the dissolved fraction is relatively small compared to that of the particulate fraction. The dissolved metal concentration peaks appeared after the hydrograph peak, suggesting transport associated with subsurface flow. For particulate metals, peaks usually occurred during the falling limb of hydrograph, implying distant-river source of metals. Particulate forms represented more than 90% of total Al, Fe, and Mn load, whereas for Cu and Zn its contributions were 52–76% and 31–56%, respectively. The high positive correlations of all particulate metals, except Zn, with suspended solid concentrations indicate that these constituents play a major role in transport of metals. Soil erosion is the main process responsible for causing elevated Al, Fe, and Mn concentrations in the river during rainfall–runoff events while Zn and Cu come mainly from the addition of slurries and manures to farmland.     

Seasonal Variations of Ten Metals in Highway Runoff and their Partition between Dissolved and Particulate Matter

Knowledge of differentiation of pollutants in urban runoff between dissolved and particulate matter is of great concern for a successful design of a water treatment process. Seasonal variations in pollutant load are of equal importance. Ten metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), as dissolved and particulate bound, was studied in the runoff from a major urban highway during a winter season and its following summer. Studded tyres and winter salting were expected to have an impact on the runoff water quality. The dissolved part of Al, Cd, Co, Cr, Mn and Ni was significantly higher in winter in comparison with summer (p?<?0.01). For Fe, however, the dissolved part was lower during winter. No significant difference was found for Cu, Pb and Zn between the two seasons. The mass concentration (mg kg^?1) for all metals was significantly higher over the summer except for Al and Co, which showed a higher mass concentration during the winter. The concentration of selected metals vs. total suspended solids (TSS) showed a linear relationship (r ²?>?0.95) during winter runoff events except for Cd. A good correlation (r ²?>?0.90) was also found for the summer period for Al, Cu, Fe, Mn, Ni and Zn. It is suggested that the metal pollutant load during winter could be assessed indirectly by measurement of TSS.     

Heavy Metals in Freshly Deposited Stream Sediments of Rivers Associated with Urbanisation of the Ganga Plain,India

Freshly deposited stream sediments from six urban centres of the Ganga Plain were collected and analysed for heavy metals to obtain a general scenery of sediment quality. The concentrations of heavy metals varied within a wide range for Cr (115–817), Mn (440–1 750), Fe (28 700–61 100), Co (11.7–29.0), Ni (35–538), Cu (33–1 204), Zn (90–1 974), Pb (14–856) and Cd (0.14–114.8) in mg kg^-1. Metal enrichment factors for the stream sediments were <1.5 for Mn, Fe and Co; 1.5–4.1 for Cr, Ni, Cu, Zn and Pb; and 34 for Cd. The anthropogenic source in metals concentrations contributes to 59% Cr, 49% Cu, 52% Zn, 51% Pb and 77% Cd. High positive correlation between concentrations of Cr/Ni, Cr/Cu, Cr/Zn, Ni/Zn, Ni/Cu, Cu/Zn, Cu/Cd, Cu/Pb, Fe/Co, Mn/Co, Zn/Cd, Zn/Pb and Cd/Pb indicate either their common urban origin or their common sink in the stream sediments. The binding capacity of selected metals to sediment carbon and sulphur decreases in order of Zn > Cu > Cr > Ni and Cu > Zn > Cr > Ni, respectively. Stream sediments from Lucknow, Kanpur, Delhi and Agra urban centres have been classified by the proposed Sediment Pollution Index as highly polluted to dangerous sediments. Heavy metal analysis in the <20-μm-fraction of stream sediments appears to be an adequate method for the environmental assessment of urbanisation activities on alluvial rivers. The present study reveals that urban centres act as sources of Cr, Ni, Cu, Zn, Pb and Cd and cause metallic sediment pollution in rivers of the Ganga Plain.     

Trace metal behaviour during summer in a stratified Mediterranean system: The Louros Estuary (Greece)

Trace metals (Al, Pb, Zn, Cr, Cu, Ni, Fe, Mn) were studied in waters (dissolved and particulate phases) and sediments of the Louros Estuary in the Amvrakikos Gulf, one of the most important European wetlands located at the NW coast of Greece. The study system is small, with a relatively narrow mixing zone, typical for Mediterranean estuaries. Particular emphasis was given to understanding the conditions prevailing in summer. During this season saline water intrudes the estuary along the river bed, despite the existing shallow sill, and forms a thin salt-wedge water mass, which occupies the near bottom layer with its thin end pointed upstream. Particulate metal concentrations within this saline bottom layer are considerably higher than in the riverine and marine sections of the estuary. Since the metal content of particles collected upstream is higher than that of the marine ones, there is a clear evidence that the salt-wedge acts as a ‘sink’ for most metals during the summer. Coexistance in the same zone of high dissolved metal concentrations indicate that loosely associated metals are desorbed from riverine particles, whereas newly formed suspended matter is deposited together with particles, transported by the river. The accumulation of metals in the near bottom layer affects directly their distribution in the sediments. The maximum concentrations of the metal fraction which is loosely held in sediments, are found primarily at the same site. The distribution of the ‘non-labile’ metal fraction of the sediments (particularly for Cu and Pb) is broadly constant throughout the estuary, confirming the absence of any significant natural or industrial point sources, at the lower part of the river. However, the analysis of sediment cores reveals an enrichment of this metal fraction at the top, near surface sections of the mouth area, indicating relatively recent pollution.     

Trace Elements in Coalbed Methane Produced Water Interacting with Semi-Arid Ephemeral Stream Channels

The objective of this study was to examine the chemistry of trace elements in coalbed methane (CBM) discharge water reacting with semi-arid ephemeral stream channels in Powder River Basin, Wyoming. The study area consisted of two ephemeral streams, Burger Draw and Sue Draw. These streams are tributaries to the perennial Powder River, Wyoming. Samples were collected bimonthly from three CBM discharge points and seven channel locations in Burger Draw and Sue Draw. Samples were also collected bimonthly from the Powder River above and below the confluence of Burger Draw. Before sample collection, pH, temperature, dissolved oxygen (DO), and turbidity were measured in the field. Samples were transported to the laboratory and analyzed for dissolved trace elements including iron (Fe), manganese (Mn), boron (B), arsenic (As), selenium (Se), and fluoride (F). Results suggest pH of discharge water was 7.1 and increased significantly in the downstream channel of Burger Draw to 8.84 before joined with the Powder River. Temperature of CBM produced water at discharge points ranged between 20.3 and 22.7 ^°C. Before discharge, DO concentrations of CBM produced water were between 1.42 and 1.5 mg/L. No significant differences in temperature, DO, and turbidity were found between Burger Draw flow and Powder River flow. However, significant differences were found within the sampling period in temperature and turbidity in flow of Burger Draw. The temperature, DO, and turbidity were all significantly different in Powder River within the sampling period. The CBM discharge water consisted of higher concentrations of F, Fe and B compared to other components. Significant changes were observed for Fe, Mn, and As; and seasonally for B. Dissolved Fe and Mn decreased, while As and Se increased in downstream channel flow. These findings will be useful in proper management of CBM produced water in semi-arid environments.     

Effects of iron-ore mining and processing on metal bioavailability in a tropical coastal lagoon

Background, aim, and scope

In water systems, water quality and geochemical properties of sediments determine the speciation of trace metals, metal transport, and sediment–water exchange, influencing metal availability and its potential effects on biota. Studies from temperate climates have shown that iron-ore mining and tailing wastewaters, besides being a source of trace metals, usually show high levels of dissolved ions and particulate suspended matter, thus having the potential of indirectly changing metal bioavailability. For the first time in the tropics, we identified the effects of iron-ore mining and processing on metal bioavailability in a coastal lagoon. With an extensive sampling scheme, we investigated the potential sources of metals; the links among metal levels in water, sediments, and invertebrates; and the contrasting effects on metal speciation and bioavailability.

Methodology

The metals Fe, Mn, Al, Cr, Zn, Cu, Ni, Pb, Cd, Hg, and As were measured in water, sediments (surface and profiles), and invertebrates from Mãe-Bá Lagoon and in the sites directly influenced by the mining operations (tailing dams and nearby rivers). In addition, samples from two other lagoons, considered pristine, were analyzed. The study area is located in the southeast of Brazil (Iron Quadrangle Region and a coastal area of Espírito Santo State). General water characteristics included pH, dissolved organic carbon, alkalinity, and anion composition. Water metal speciation was assessed by a speciation model (Chemical Equilibria in Aquatic Systems). Grain-size distribution, organic carbon, carbonate, and acid volatile sulfide (AVS) were determined in sediments. Statistical methods included comparison of means by Mann–Whitney test, ordination and correlation analyses, and analysis of regression for geochemical normalization of metals with grain size.

Results and discussion

The dissolved metal concentrations, the total metal levels in sediments, and the normalization based on the fine sediment fraction showed that the mining operations constitute potential sources of Fe, Mn, Cr, Cu, Ni, Pb, As, and Hg to Mãe-Bá Lagoon. However, trace metal availability was reduced because of increased pH, hardness, and sulfide content (356 μmol/g) in the sites influenced by the mining. The lagoon showed similar water chemistry as in the mining sites, with metal bioavailability further decreased by the presence of dissolved organic carbon and chloride. Although AVS levels in the lagoon were low (0.48–56 μmol/g), metal bioavailability was reduced because of the presence of organic matter. Metal levels in invertebrates confirmed the predicted low metal bioavailability in Mãe-Bá Lagoon. The lagoon was considered moderately contaminated only by Hg and As.

Conclusions

The iron-ore mining and processing studied here constitute potential sources of metal pollution into the tropical lagoon. Contrary to expectations, however, it also contributes to reducing the overall metal bioavailability in the lagoon.

Recommendations and perspectives

These findings are believed to be useful for evaluating metal exposure in a more integrated way, identifying not only the sources of pollution but also how they can affect the components involved in metal speciation and bioavailability in water systems, leading to new insights.     

Heavy metal inputs to Mississippi Delta sediments

Heavy metal concentrations were determined in suspended particulates, filtered water and sediment collected in the Mississippi River and from its marine delta. More than 90% of the metal load of the river is associated with particulate matter, which is relatively constant in chemical composition with time and place. The Mississippi River suspended material is similar to average crystal rocks in Fe, Al, V, Cr, Cu, Co, Mn, and Ni concentration but is generally enriched in Zn, Cd and Pb. Sediment cores dated by the Pb 210 method show that the Cd and Pb enrichments are recent phenomenon and are most likely due to the activities of man. About 6000 tonne of Pb and 300 tonne of Cd are being added to the delta sediments by man each year, more than 30 times the amount added to the Southern California Bight. River particulate matter is essentially identical to deltaic sediments in Al, Fe, Cr, V, Cd and Pb concentration, but the sediments are depleted in Co, Cu, Mn, Ni and Zn by 20 to 40%. Chemical leaching of the solids show the metal losses to be primarily from the oxide phase, suggesting diagenetic reduction and mobilization as a mechanism. Trace metal concentrations in filtered Mississippi River water were below the limits for safe drinking water and were similar to world average river values. The abundant river suspended matter and high pH combine to keep dissolved trace metal concentrations low.     

Fractionation and Distribution of Metals in Guadiamar River Sediments (SW Spain)

Traditionally, the Guadiamar River (Seville, Southwest Spain) has received pollution from two different sources, in its upper section, from a pyrite exploitation (Los Frailes mine) and, in its lower section, from untreated urban and industrial wastes and from intensive agricultural activities. In 1998, the accidental spillage of about 6 million m³ of acid water and sludge from mine tailings to Guadiamar River worsened the pollution of an already contaminated area. The main polluting agents of the spillage were heavy metals. The total concentration of a metal provides scarce information about the effects on environmental processes or about the toxicity of the sediment samples. A more sophisticated fractionation of the sediment samples based on a species distribution can help to understand the behaviour and fate of the metals. This article describes a distribution study of the metals Al, Cd, Cu, Fe, Mn, Pb and Zn by fractionation analysis of sediments from eleven sample sites alongside the Guadiamar Riverbed. The samples were collected in summer 2002, four years after the spillage and after the area had been cleaned. Sequential extraction analysis resulted in the definition of four fraction categories: exchangeable metal (the most available fraction), reducible metal (bound to hydrous oxides of Fe and Mn), oxidizable metal (bound to organic matter and sulphides) and a residual fraction (bound to minerals). Significant increases in the available fraction of several potentially toxic metal ions like Cd, Mn and Zn were found. The distribution pattern was variable along the River. At the site closest to the mineworks, the soluble forms of Cd, Mn and Zn were significantly more abundant that those downstream. Cu and Pb were present in the reducible fraction while Fe was present associated in the residual fraction.     

Historical trends of airborne trace metals in Detroit from 1971 to 1992

Ambient concentrations of particulate Fe, Zn, Ph, Ni, Cr, Cd and Hg were measured at nine sites located in the metropolitan area of Detroit from 1971 to 1992. The ambient concentrations of all the trace metals were found to be generally higher at industrial and commercial sites. The concentrations show significant variations between residential and commercial areas and between residential and industrial areas; however, no significant variation was found between the industrial and commercial settings. The spatial variation of trace metal levels within the urban area was influenced by the frequency distribution of the wind direction as well as type and location of emission sources. The ambient concentrations of the trace metals during the decade of 1971–1981 declined by 37–88%. In the 1980s many of the trace metals reversed this trend with the exception of Fe and Pb which continued to decline at annual rates of 2% and 9.8%, respectively. The sharp decrease in Pb concentrations during the 1980s, reflected the significant reduction of Pb content in gasoline from 0.28 g/liter in the 1982 to 0.026 g/liter in the 1989. The ambient concentrations of Zn, Ni, Cr, Cd and Hg showed an upward trend during the 1980s with an annual rate in the range of 0.6% to 10.6%. The long-term trends of selected U.S. market parameters, analyzed as potential long-term indicators of emission sources activityies, were consistent with the changes of ambient concentrations, the correlation coefficient being in the range of 0.58 to 0.84 for most of the trace metals.     

Spatial distribution of soil heavy metal concentrations as indicator of pollution sources at Mount Križna (Great Fatra,central Slovakia)

The objective of this study was to test the suitability of a simple approach to identify the direction from where airborne heavy metals reach the study area as indication of their sources. We examined the distribution of heavy metals in soil profiles and along differently exposed transects. Samples were taken from 10 soils derived from the same parent material along N-, S-, and SE-exposed transects at 0—10, 10—20, and 20—40 cm depth and analyzed for total Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn concentrations. The heavy metal concentrations at 0—10 cm were larger than background concentrations in German arable soils except for Cr (Cd: 0.6—1.8 mg kg^—1; Cr: 39—67; Cu: 40—77; Ni: 87—156; Pb: 48—94; Zn: 71—129; Fe: 26—34 g kg^—1; Mn: 1.1—2.4). Decreasing Cd, Cu, Mn, and Pb concentrations with increasing soil depth pointed at atmospheric inputs. Aluminum and Ni concentrations increased with soil depth. Those of Fe, Cr, and Zn did not change with depth indicating that inputs at most equalled leaching losses. The Pb accumulation in the surface layer (i.e. the ratio between the Pb concentrations at 0—10 to those at 20—40 cm depth) was most pronounced at N-exposed sites; Pb obviously reached Mount Križna mainly by long-range transport from N where several industrial agglomerations are located. Substantial Cd, Cu, and Mn accumulations at the S- and SE-exposed sites indicated local sources such as mining near to the study area which probably are also the reason for slight Cr and Zn accumulations in the SE-exposed soils. Based on a principal component analysis of the total concentrations in the topsoils four metal groups may be distinguished: 1. Cr, Ni, Zn; 2. Mn, Cd; 3. Pb (positive loading), Cu (negative loading); 4. Al, Fe, indicating common sources and distribution patterns. The results demonstrate that the spatial distribution of soil heavy metal concentrations can be used as indication of the location of pollution sources.     

A mass-balance analysis of trace metals in two weedbeds

A mass-balance approach was used to examine the role of macrophyte beds as a sink or source for 7 metals over time scales varying from two months (the growing season of the plants) to one year. During the growing season the macrophyte beds were found to be net sinks for particulate metals but were net sources of dissolved metals. During senescence, ca. 15–20% of the Al, Fe, and Mn and ca. 25–30% of the Cr, Cu, Ni and Zn within the macrophyte tissues at maximum seasonal biomass was lost to the surrounding waters in a dissolved form. The export of metals from the weeds during senescence was a very small fraction (<0.01% of Al, Fe to 3.5% of Zn) of the annual allochthonous metal loading to Fitch Bay in L. Memphremagog, Quebec. In L. Weedon however, metal export during senescence was 34% (Mn) to 57%(Cu) of the annual allochthonous load. The time estimated for the plants to recycle the metals within the rooting zone of the sediments was on the order of hundreds of years. These results demonstrate that while weedbeds are net sources of metals during the summer, only a small fraction of metals in littoral sediments are not permanently buried over the longer term.     

西藏尼洋河水体重金属分布特征及风险评价

重金属含量是影响水生态环境安全的重要因素,该文意在探索西藏河流水体重金属变化规律。研究了雅鲁藏布江第二大支流尼洋河的Zn、Cu、Mn、Cd、Fe5种重金属含量时空变化特征和相关性,以及迁移变化机理,对重金属富集程度和污染风险进行了评价。结果表明:尼洋河重金属含量源头较低,中上游位置有突变。Fe、Mn、Cd是影响水质变化的敏感因子。Zn、Cu、Mn含量平水期枯水期丰水期。丰水期重金属含量主要受人类活动或水文气象活动影响,平水期及枯水期的Zn、Cu、Mn、Fe含量主要受自然过程影响,枯水期Cd主要受人类活动影响。水库对重金属富集有一定的影响。河源和中下游河段污染较轻,上游河段重金属综合污染指数最高。     

Ecogeochemical investigation,Kola peninsula: Sulphur and trace element content in snow

The Central Kola Expedition and the Geological Surveys of Norway and Finland have undertaken a multi-media investigation of eight catchments situated in Russia (Zapoljarniy, Monchegorsk, Kirovsk, Kurka), Norway (Skjellbekken) and Finland (Kirakka, Naruska, Pallas) to determine the environmental impact of local industrial pollution. Results of analysis of snow samples collected in March/April 1994 are presented for both filtered meltwater and filter residues. Many heavy metals (As, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn), as well as S, Al and Fe, are unusually enriched in both phases in the Russian catchments, primarily in Monchegorsk and/or Zapoljamiy. Typically, some elements are found mostly in the meltwater phase (e.g. Na, S, Sr, Zn), others in the filter residues (e.g. Cr, Fe, Mo, Ni). Cu and Ni are well correlated, both in meltwater and in filter residue, and the ratio of Cu to Ni can be useful in identifying pollution sources. Snow is a well-suited medium for fingerprinting environmental pollution sources. Estimates of deposition from snow meltwater only, will be seriously underestimated for many elements.     

Impacts of Metal Contamination in Calcareous Waters of Deûle River (France): Water Quality and Thermodynamic Studies on Metallic Mobility

To evaluate adverse impacts of metal pollution originating from smelting activities on the aquatic ecosystem of Deûle river in northern France, water samples were collected from five selected stations along a contaminated region of this river (during two surveys: April–June 2005 and April–May 2007). All samples were analysed using inductively coupled plasma (ICP) atomic emission spectroscopy and/or ICP-mass spectrometry. Both the concentrations of dissolved and particulate elements were determined, and analytical data were compared with national and international water/particle quality guidelines as well as with some values reported in the literature for polluted rivers. For all the metals studied (i.e. Cd, Cr, Cu, Mn, Ni, Pb and Zn), our investigations showed that the effects of the dissolved phase on this aquatic medium were weak, according to water quality status established by US Environmental Protection Agency, USEPA (1994, 1999). Conversely, the levels of metals in suspended particulate matter were found to be much higher than local background contents and natural reference levels in French catchments. These levels were further quantified as “serious” contamination, i.e. above the “red” range that was previously elaborated by most existing metal-contamination scales in French basins of similar geology. The affinity of these metals for the particulate phase in Deûle waters follows the order: Cd >Cr > Pb > Zn = Mn > Cu > Ni. The trace metals released from anthropogenic activities were found to be partly bound to the reactive particulate phase, calcite, which is sensitive to physico-chemical variations occurring in the river ecosystem. To appraise the risk of ecotoxicity by metals, predictions on the ability to release metallic pollutants from calcite into waters were made successfully by testing three equilibrium geochemical speciation models (JCHESS, VISUAL MINTEQ and WINHUMIC) in which soluble organic matter was taken into account. Calculations showed that metal–water–calcite systems in Deûle River are close to thermodynamic equilibrium with generation of solid solutions, MeαCa_1-αCO₃, by (co)precipitation and/or adsorption reactions. On the basis of results mentioned here, more measurements of river chemistry and assessments of predictive capabilities of chosen water-quality guidelines with time would be developed in aquatic and calcareous areas for controlled dredging operations or other treatment engineering works.     

Distribution,risk assessment,and source analysis of heavy metals in sediment of rivers located in the hilly area of southern China

Purpose

River sediment, the important sink and source of heavy metals, can provide critical information for aquatic ecosystem health. Heavy metal pollution has been a serious problem facing river systems worldwide and can adversely affect human beings via the food chain. However, no comprehensive study has been conducted on heavy metal pollution in sediments of river systems in the hilly area of southern China, which plays a key role in water supply and ecosystem balance. This study is aimed at comprehensively studying the pollution status of heavy metals in river sediments in the hilly area of southern China and apportioning sources.

Materials and methods

A total of 39 superficial sediment samples were collected from the upstream, midstream, and downstream of 13 rivers (Xiangjiang River, Zishui River, Yuanjiang River, and Lishui River located in Hunan Province; Ganjiang River, Xinjiang River, Fuhe River, Raohe River), and Xiushui River located in Jiangxi Province; Qiantangjiang River and Oujiang River located in Zhejiang Province; Minjiang River and Jiulongjiang River located in Fujian Province) in the hilly area of southern China. The total concentrations of metals of Mn, Zn, Cr, Co, Ni, Cu, As, Cd, Sb, Pb, and V were analyzed using the inductively coupled plasma-mass spectrometry method. The pollution status and potential ecological risk were assessed with the geoaccumulation index (I_geo), sediment quality guidelines (SQGs), and potential ecological risk index (RI). The source apportionment of heavy metals was performed by correlation analysis and principle component analysis (PCA).

Results and discussion

Results indicated that Mn, Zn, and Pb concentrations were significantly higher than other metals, especially in the upstream of the Jiulong River and midstream and downstream of the Xiangjiang River. Pollution assessment indicated that Cd pollution of sediments was most serious and that more than 50% of sampling sites were significantly polluted, with a very high potential ecological risk. The rivers in Hunan provinces (HN) were identified as the priority controlled rivers because of the high I_geo and RI index values. Correlation and PCA analysis indicated that Mn, Pb, and Zn originated from natural and mineral exploitation activities; As, V, Ni, and Sb originated from industrial wastewater and mineral-smelting activities; Cu and Co originated from agricultural activities; Cr and Ni originated from natural sources. While the most polluted Cd came from a combination of multiple sources described above.

Conclusions

Results indicated that Cd was the most common heavy metal pollutant, especially in river sediments of Hunan Province. Anthropogenic activities have become the main source of heavy metals in the river sediments of the hilly area of southern China. Special attention should be paid to Cd, and measures must be taken to prevent from further anthropogenic influence on heavy metal pollution.

     

Geochemistry of Trace Elements in the Ground Water of Cuttack City,India

The concentration of some trace metals, like Fe, Mn, Cu, Pb, Zn, Co, Cr and Ni, was measured in the potable water of Cuttack City,India during winter, summer and rain events in the course of a two year period. Apart from Fe, all other trace metals fell well within the maximum permissible limit set by WHO for drinking water. On the basis of spatial/temporal variations, weathering of rocks and anthropogenic input were found to be main sources of trace elements in the ground water. The considerable temporal changes indicate that a majority of trace metals is entering the aquifer during rain fall.Factor analysis of the trace element data suggest that Fe, Mn and Cr are interrelated with each other and derived significantly from the aquifer, whereas input of Pb and Co may be due to atmospheric deposition in the study area.     

内蒙古草原白乃庙铜矿区土壤重金属污染特征研究

对位于内蒙古荒漠草原上的白乃庙铜矿采选矿区土壤和尾矿区周围土壤重金属污染状况进行了调查研究。结果表明,矿区土壤中Cu、Cr、Ni、Fe和Mn浓度均高于内蒙古土壤平均值。单因子指数法评价结果表明,五个调查区域土壤都受到了重金属Cu、Cr、Ni、Mn、Fe的污染,其中Cu为重污染,Cr、Ni、Mn、Fe为轻污染,Pb为安全级别,Zn和As只对某些区域有轻污染。综合污染指数法评价结果表明,五个调查区域的土壤重金属污染等级均属重污染,主要贡献元素是Cu,其次是Cr、Ni、Mn、Fe,这与尾矿砂中这些重金属的浓度是相对应的。由于周边地形复杂,多为低山丘陵,所以该地区主导风向对于尾矿库区不同方向土壤重金属污染水平的影响差异并不显著。     

巢湖表层沉积物中重金属的分布及污染评价

对巢湖湖区不同位点的表层沉积物中的Fe、Cr、Pb、Cu、Co、Zn、Ni7种重金属含量进行的分析表明,湖泊沉积物中重金属含量分布呈现一定的区域特征,由于巢湖西半湖靠近合肥市区,大量的工业废水和生活污水通过河道排入巢湖,引起西半湖区中重金属含量高于东半湖区。采用富集因子法和地积累指数法对巢湖沉积物重金属污染现状进行了评价,结果表明,巢湖沉积物中存在Pb、Cu污染,个别地区已相当严重,并呈现沿湖心区至东半湖区逐渐降低趋势。研究表明,两种方法均能对人为污染行为做出较为科学的评价,且两种方法得到的评价结果基本一致。由于重金属元素有很强的毒性,并且能够在食物链中传递,有关部门应及早从流域环境综合规划入手,对重金属污染问题采取有力的控制对策,保护沿湖地区居民免受危害。此外,对巢湖表层沉积物中重金属污染物来源进行了初步分析,据分析结果判断,巢湖沉积物中重金属总量Co、Fe、Cr的来源相似,Zn和Cu的来源相似。     

滇池内湖滨带重金属污染及其生态风险评价

水体沉积物是重金属元素的重要载体,其含量高低能反映水环境质量现状。采集滇池内湖滨带沉积物样品,分析了滇池内湖滨带表层沉积物中Pb、Cd、Cu、Zn、Cr、Ni、Fe、Mn 8种重金属元素含量特征,并用Hakanson潜在生态危害指数法评价其生态危害,旨在为合理预防和治理滇池内湖滨带的重金属污染以及内湖滨带生态系统的修复提供基础资料。结果表明,与“全国土壤环境质量标准”对比,表层沉积物中主要是Cd、Cu、Zn超标,重金属污染强度总体上是草海＞外海。不同重金属间的相关性分析结果表明,Cu-Cd之间呈极显著相关,说明这两种元素污染源可能相同,几种污染重金属与胶体矿物元素Fe、Mn间的相关性不大,说明在所调查沉积物中,Fe/Mn氧化物或氢氧化物共沉淀或吸附Pb、Cd、Cu、Zn、Cr、Ni元素量较少。由潜在生态风险评价结果可知,滇池内湖滨带表层沉积物已具极强生态危害,各重金属对滇池内湖滨带生态风险影响程度由高到低依次为：Cd〉Cu〉Pb〉Ni〉Zn≈Cr。