Trace metals in sediments and aquatic plants from the Xiangjiang River, China

Purpose

The metal concentrations and Pb isotopic composition in sediments and plants from the Xiangjiang River, China, were investigated to understand the contamination and potential toxicity of metals in sediments; to determine the accumulation and distribution of metals in plant tissues; and to trace the possible pollution source of Pb in sediments and plants.

Materials and methods

Sediments and plants were collected from 43 sampling sites in the study region. After sediments were air-dried and passed through a 63-??m sieve, they were acid-digested and DTPA-extracted for determination of total and bioavailable metals. The plants were separated into roots, leaves, and stems; dried; cut into pieces; and digested with HNO₃?CH₂O₂. Metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) and Pb isotopic composition were analyzed by inductively coupled plasma-mass spectrometry.

Results and discussion

Maximum As, Cd, Cr, Cu, Ni, Pb, and Zn concentrations in sediments were 47.18, 55.81, 129.5, 161.6, 160.4, 430.7, and 1,098.8?mg?kg^?1, respectively. The bioavailable fractions of As, Cd, Cu, Pb, and Zn had significant linear relationship with their corresponding total contents in sediments while no significant relationship was observed between bioavailable and total contents of Cr and Ni. In general, plant tissues showed higher As, Cd, Cu, Pb, and Zn concentrations and lower Cr and Ni concentrations compared with sediments. The ²⁰⁶Pb/²⁰⁷Pb ratios decreased in the order of total > bioavailable > stems ?? leaves > roots. A strong linear correlation was observed between the ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁶Pb/²⁰⁷Pb ratios of the plant tissues, sediments, and the possible pollution sources of Pb in the Xiangjiang River.

Conclusions

As, Cd, Cu, Pb, and Zn demonstrated higher contamination levels in sediments and plants compared with Cr and Ni. Cd had highest potential ecological risk. The Pb from anthropogenic sources with low ²⁰⁶Pb/²⁰⁷Pb ratios was preferentially associated with the bioavailable fractions in sediments and accumulated in roots. The Pb in plant tissues is mainly derived from the Pb in sediment and is taken up through the sediment-to-root pathway.     

杭州市城市土壤中重金属、磷和其它元素的特征

Health implications of inhaling and/or ingesting dust particles with high concentrations of heavy metals from urban soils are a subject of intense concern. Understanding the geochemistry of these metals is key to their effective management. Total concentrations of heavy metals, phosphorus (P) and 8 other elements from topsoil samples collected at 82 locations in Hangzhou City were measured to: a) assess their distribution in urban environments; and b) understand their differentiation as related to land use. Metal mobility was also studied using a three-step sequential chemical fractionation procedure. About 8.5%, 1.2%, 3.6%, 11.0% and 30.3% of the soil samples had Cd, Cr, Cu, Pb, and Zn concentrations, respectively, above their allowable limits for public and private green areas and residential use. However, in commercial and industrial areas, most samples had metal concentrations below their allowable limits. Statistical analyses revealed that the 16 measured elements in urban soils could be divided into four groups based on natural or anthropic sources using a hierarchical cluster analysis. Additionally, Cu, Pb, and P showed similar spatial distributions with significant pollution in commercial zones, suggesting vehicle traffic or commercial activities as dominant pollutant sources. Also, Cd, Co, Cr, Ni, Zn, Mn and Fe had the highest concentrations in industrial locations, signifying that industrial activities were the main sources of these seven metals. Moreover, the data highlighted land-use as a major influence on heavy metal concentrations and forms found in topsoils with large proportions of soil Cd, Co, Cr, and Ni found in residual fractions and soil Cu, Pb and Zn mainly as extractable fractions.     

Long-term dispersal of heavy metals in a catchment affected by historic lead and zinc mining

Purpose

The Matylda catchment, in southern Poland, was polluted by the discharge of mine waters from a lead and zinc mine that inundated parts of a valley floor and caused the accumulation of metal-polluted sediments. After a partial reclamation of the mine site in the early 1980s, polluted sediments continue to accumulate on downstream floodplains and in fishponds. The aim of this study was to reconstruct the changes in metal dispersal during 100?years of mining and during the 40-year post-mining period and to propose a strategy for pollution mitigation in the area.

Materials and methods

Analyses of Cu, Cd, Pb, Zn, Mn, Ca, Mg and Fe concentrations, speciation of heavy metals and mineralogical analyses were undertaken on overbank sediment cores and in stream sediments. Concentrations of the same elements and macro-ions soluble in stream waters were also determined.

Results and discussion

Concentrations of Zn, Cd and Pb in the sediment profiles vary between 40,000 and 55,000, 300 and 600 and 30,000 and 50,000?mg?kg^-1, respectively. Changes of metal concentrations and the stratigraphy of sediments from the floodplains, stream channels and fishponds suggest rapid changes of metal loads migrating downstream during both the mining and post-mining periods. Since the time of mine closure, fine-grained, mine-derived sediments (ca. 12?cm thick) have been the main source of pollution of post-mining sediments and surface waters. Closure of the mine was followed by a relatively short period of rapid redistribution of sediment-associated heavy metals in the stream channel. Since the 1980s, the floodplain and fishponds have received a constant supply of metals. It contrasts with the slow sediment accretion rate and a rapid decrease of metal concentrations in floodplain pools due to dilution by decomposed leaf litter. A fivefold increase of Cd content in waters over the 4.6?km reach of the Matylda stream indicates continuous leaching of this element from the contaminated valley floor.

Conclusions

Unsuccessful mine site rehabilitation is due to leaching of mine-originated sediments dispersed over the valley bottom. However, the rate of metal remobilization over the last 40?years is low because of the small thickness and widespread anoxic conditions that prevail within both recent and mine-originated sediments and the alkaline pH of stream water, which reduces metal mobility. Distribution of the contaminated layer over a large area of the valley bottom precludes cost-efficient catchment rehabilitation.     

National parks in Great Britain and the achievement of nature conservation purposes

The ten National Park Authorities of England and Wales are concerned mainly with landscape conservation and provision for outdoor recreation. Nature conservation is not primary park purpose and only authority has its own nature reserves. Nature conservation purposes are pursued in the parks as elsewhere by the Nature Conservancy Council and by the appropriate County Conservation Trust. The achievements of these two organisations—the former national and governmental, the latter local and voluntary—are compared and contrasted.The number of national Nature Reserves established by the Nature Conservancy nationally assessed. The Conservacy appears to have treated the parks much as it has treated the rest of the country. Local Conservation Trusts have also accorded the parks no more—but also no less—attention than elsewhere. Trust reserves tend to be more or less uniformally distributed throughout the counties of England and Wales. This pattern corresponds with the distribution of Trust members and arises because membership rates tend to be highest in the more rural areas (including the National Parks) where absolute population levels are low. Finally, the National Park Authorities themselves have all but neglected nature conservation purposes in the parks. This lack of interest is consistent with the low priority afforded to nature conservation by local authorities in general and by rural authorities in particular. But whilst past achievements have been slight, future prospects are, by comparison, quite bright.     

Effects of anthropogenic silt on aquatic macroinvertebrates and abiotic variables in streams in the Brazilian Amazon

Purpose  

While environmental risks associated with petroleum extraction such as oil spills or leaks are relatively well known, little attention has been given to the impacts of silt. The increase in petroleum exploitation in Amazonia has resulted in sediment input to aquatic systems, with impacts on their biodiversity. Here we use a combination of field measurements and statistical analyses to evaluate the impacts of anthropogenic silt derived from the construction of roads, borrow pits, and wells during the terrestrial development of gas and oil, on macroinvertebrate communities in streams of the Urucu Petroleum Province in the Central Brazilian Amazon.     

A review of fertilizer, lime and organic manure use on farm crops in Great Britain from 1983 to 1987

Abstract. In 1983, an annual Survey of Fertiliser Practice in England and Wales was extended to Scotland, to provide comprehensive information on inorganic fertilizer, lime and also organic manure use in mainland Britain. It was based on an annual sample of about 1500 farms, selected from the Agricultural Census and stratified by farm type and size. Results from the first fifteen years (1983–97) show that fertilizer nitrogen (N) rates on both tillage crops and grassland peaked at 157 and 132 kg ha^–1, respectively, in the mid 1980s and subsequently decreased by c.10%. The majority of N was applied in straight form (without P or K) to tillage crops and in compound form (containing two or more nutrients e.g. NPK; NK) to grassland. Total N use on cereals showed little change but autumn‐applied N decreased on both winter cereals and winter oilseed rape. Total N rates decreased on oilseed rape and, to a smaller extent, on maincrop potatoes and sugarbeet. Between 1983–87 and 1993–97, mean phosphate (P₂O₅) rates declined by almost 10% on both tillage crops (from 58 to 53 kg ha^–1) and on grassland (from 25 to 23kg ha^–1). The corresponding mean potash (K₂O) rates decreased slightly on both tillage crops (from 64 to 62 kg ha^–1), and on grassland (from 32 to 31 kg ha^–1), although annual usage was more variable on grassland. Sulphur use increased appreciably on cereal and oilseed rape crops between 1993, when S data were first recorded in the survey, and 1997 when 13% and 30%, respectively, of these crop areas received S‐fertilizer. However, on grassland, S use remained very low. Average lime use increased on both tillage crops and grassland between the mid 1980s and mid 1990s, from 10 to 12% and 4 to 7% of the total area, respectively. The proportion of land receiving organic manures remained at c. 16% for tillage cropping but increased slightly for grassland, from a mean of 40% in 1983–87 to 44% in 1993–97. Manures were applied throughout the year but about half the applications to tillage land, and a quarter of those to grassland, were made in autumn when the risk of subsequent nitrate leaching loss is greatest.     

Prevalence of overweight and obesity among young people in Great Britain

OBJECTIVE: To determine the prevalence of overweight and obesity in British young people (4-18 years) in 1997. DESIGN: Cross-sectional analysis of the National Diet and Nutrition Survey of young people. SETTING: Great Britain. SUBJECTS: Nationally representative sample of 1836 young people (age 4-18 years). RESULTS: The prevalence of obesity based on body mass index (weight/height(2)) and the International Obesity Task Force cut-offs was 4.0%, with a further 15.4% identified as overweight. Asians were almost four times as likely to be obese as white subjects (13.6 vs. 3.5%, P<0.001). Among white subjects there was no significant difference in the prevalence of obesity between girls and boys, or with age. The risk of obesity was significantly higher in subjects from social classes IV and V than from social classes I-III (6.5 vs. 2.7%, P=0.003). Subjects living in Scotland and Wales were significantly more likely to be obese than those in England (7.6 and 6.5 vs. 2.9%, respectively, P<0.01). Multiple logistic regression showed that, among white subjects, those in social classes IV and V living in Wales and Scotland were three times more likely to be obese than the other children in the survey (odds ratio 3.3, 95% confidence interval 1.1-9.8). CONCLUSION: These data provide information on the national prevalence of overweight and obesity in Great Britain and baseline data from which to monitor future trends. This analysis provides important demographic information on those most at risk of obesity, which may be used to inform public health strategies to prevent obesity in young people.     

Empirical models for estimating the concentrations and exports of metals in rural rivers and streams

Concentrations of Al, Fe, Mn, Zn and Cu were measured monthly at 24 sites in 21 rivers in Ontario and Quebec. Relationships between metal and suspended particulate matter (SPM), turbidity, colour (g440), temperature and system hydrology were quantified, and used to derive empirical models for predicting metal concentrations. In a test of the models using an independent data set, they explained a significant proportion of the variation in Al (90%), Fe (85%), and Mn (57%), but only 37% of the variation in riverine Zn concentrations. Metals concentrations are most strongly associated with SPM concentrations. The proportion of the total metal load associated with particulates (>0.45 μm) is highly variable below 10 ppm SPM, indicating that this concentration approximates the division between systems dominated by weathered (solution) versus eroded (particulate) inputs. Annual metal exports were calculated, and empirical models for predicting catchment exports were developed using system hydrology and average SPM concentrations. These simple models can be used to estimate metals concentrations and exports from routine water quality monitoring data, without requiring chemical analyses. They also serve to distinguish background levels from those indicating metal contamination, and will, therefore, be useful for water quality evaluation.     

Spatial network analysis of surface soil pollution from heavy metals and some other elements: a case study of the Baotou region of China

Purpose

With the development of heavy industry, urban soil suffers serious pollution, which threatens the sustainable development of cities. Understanding the spatial distribution characteristics of surface soil pollution aids in pollution prevention and control and promotes sustainable development.

Materials and methods

We use China’s Baotou as an example. Based on the data of 2820 sampling points in main urban areas and some suburban areas of Baotou, we constructed a relationship network model for sampling points in surface soil by using the complex network method. We combined the network method with spatial geographic information to analyze the spatial agglomeration characteristics of the surface soil pollution in Baotou China.

Results and discussion

Sampling points at Dalahai Village (including 506D, 538B, and 538D) and Hayenaobao Village (including 509C, 541A, and 541C), Puerhantu Town within the Kundulun District have the most serious pollution problems, and they are all concentrated in the tailings dam. Sampling points 328D and 544A are scattered in the Leng Community, Kunhe Town, Kundulun District and Changhan Village, Haringer Township, Jiuyuan District, but they have a close co-anomaly relationship with the tailings dam. We suggest that these areas should be unified to give priority to pollution control. There is an obvious difference for Al₂O₃, B, Hg, and U, which are abnormal in the power plant ash storage pools, but normal at the tailings dam. Consequently, pollution control for power plant ash storage pools needs to be different from pollution control at the tailings dam. Sampling points at the Fengying Community (including 580A and 580B), Kunhe Town, Kundulun District, and Gaoyoufang Village (579D and 643B), Rare Earth Road, Qingshan District as well as other sampling points upstream of the Kundulun River have a close co-anomaly relationship with the tailings dam. It is necessary to strengthen the purification treatment of sewage upstream of the Kundulun River to reduce the spread of pollutants.

Conclusions

These results provide a theoretical basis for the government to formulate specific cross-regional collaborative governance measures.

     

Critical drainage and nitrate leaching losses from manures applied to freely draining soils in Great Britain

Abstract. Pig slurry was applied by open-slot injection to experimental plots on a sandy loam site at ADAS Gleadthorpe, Nottinghamshire. Volume and distribution of over-winter drainage were adjusted through the use of rainfall exclusion covers or irrigation. The resultant slurry N leaching over the range of drainage values tested (up to 300 mm) could be satisfactorily described by curve-fitting, using a quadratic or exponential function. Initial simulations of slurry N leaching using the manure nitrogen decision support system manner (v. 3.0) compared poorly with the experimental data, predicting both earlier and greater amounts of nitrate leaching. However, the lack of fit could be explained by consideration of the likely ammonia emissions following slurry injection, the actual volumetric soil moisture capacity at the experimental site and the likely time delay for the nitrification of slurry N following application. Good agreement between modelled and observed data was achieved when these factors were taken into account. The manner model was used to simulate nitrate leaching beyond the range of drainage treatments tested in the experiments and the anticipated sigmoidal relationship between nitrate leaching and drainage was observed. The model was then used to study the effects of manure application timing and the likely impact on nitrate leaching, across the range of rainfall conditions found in Great Britain. Simulations for a range of manure types were undertaken, with manures applied at rates up to the limit of permitted N loading on freely draining sandy loams. Rainfall inputs for these simulations were based on long-term average climatic data. Results are presented for two contrasting manure types, cattle slurry and poultry manure, both of which are subject to controls in Nitrate Vulnerable Zones (NVZs) in Great Britain.     

The effect of surface growth of blue-green algae and bryophytes on some microbiological,biochemical, and physical soil properties

Summary The influence of surface growth of inoculated cyanobacteria (blue-green algae) on subsurface properties of a brown earth, silt loam soil was studied in reconstituted flooded soil columns. One blue-green algae species, Nostoc muscorum, become dominant within the first 7 days of inoculation. In light control columns (not inoculated) a bryophyte, Barbula recurvirostra, was dominant although significant growth of indigenous blue-green algae occurred. The blue-green algae counts were in the range of 1×10⁶ g^-1 dry soil in the surface layer (0–0.7 cm) in both columns. Any effect of surface phototrophic growth on soil properties was restricted to the surface layer. In inoculated columns there was a twofold increase in microbial biomass and an eightfold increase in bacterial numbers by week 13. However, bacterial numbers declined so that there was only a 2.8-fold increase by week 21. Dehydrogenase (x2.1), urease (x2.8) and phosphatase (x3.1) activities and polysaccharides (+69%) increased by week 21 as a result of the blue-green algae inoculation along with a significant improvement in soil aggregation. However, similar increases occurred in the light control columns, indicating that given appropriate conditions of light and moisture indigenous species may be ultimately as effective as introduced species in bringing about biochemical and microbiological changes to soil.     

Distribution of some heavy metals in organisms in Hardangerfjord and Skjerstadfjord,Norway

Near Odda, in West Norway, metal-bearing waters enter the Sorfjord, a tributary of the Hardangerfjord. Unusually high concentrations of Cd, Pb, and Zn are present in marine life over a considerable length of the fjord. Marine life near Odda also contained concentrations of Hg higher than normal. At Fauske, in North Norway, marine organisms contain high concentrations of Cu, but this contamination is confined to a small area of the Skjerstadfjord system.     

The carbon content of soil and its geographical distribution in Great Britain

Abstract. England and Wales have 155 314 1 × 1 km squares, of which 140049 have more than 50% soil cover. The total soil organic carbon content, based on the dominant soil series and dominant land cover type, is estimated to be 2773 × 10⁶ t C. Scotland has 84929 1 × 1 km squares, of which 82 420 have a nominated dominant soil series. The total soil organic carbon content is estimated to be 19011 × 10⁶ t C, 6.85 times the total organic carbon content of the soil of England and Wales. The total organic carbon content of the soil of Great Britain is estimated to be 21 784 × 10⁶ t C, of which 87% is in Scottish soils and 75% is in Scottish peats. A map of the mean soil organic carbon content of 10 × 10 km squares of the National Grid using classes of equal range illustrates the narrow range of organic carbon contents of the soils of England and Wales and the dominance of organic carbon in Scottish soils. A map using the same data, but with classes of unequal ranges increasing in size with increasing carbon content, is better for showing detailed differences within England and Wales.     

Environmental impacts of surface mining on mined lands,affected streams and agricultural lands in the Dabaoshan Mine region,southern China

Impacts of surface mining on ecosystems were investigated in the Guangdong Dabaoshan Mine region, southern China. Significant soil acidification has been induced by mining activities which cause oxidation of metal sulfides contained in the mine spoils. Natural colonization of vegetation in the mine site has been impeded and this has resulted in severe soil erosion. Acid mine drainage from this mine site has caused the degradation of the downstream aquatic ecosystems. Mine water with pH< 3·5 has been continuously flowing into a first‐order tributary of the Beijiang River and has destroyed all the aquatic life to a distance of at least 25 km downstream of the discharge point, even when the pH rose to above 6 in the Hengshishui River (a third‐order tributary of the Beijiang River). Further downstream, macroinvertebrates first occurred at about 30 km from the discharge point, and only one species was found. This is in contrast to a reference site that was not affected by acid mine drainage, where 36 macroinvertebrate taxa were found. Acidic mine water also had marked impacts on the agricultural lands irrigated with it. Severe contamination of the soils by mine drainage is responsible for the extremely high concentrations of some heavy metals in the edible portions of a variety of food crops grown on the agricultural lands. Copyright © 2005 John Wiley & Sons, Ltd.     

在法国前铅和锌冶炼厂附近的城市土壤重金属的污染、分离和利用

smelters in Northern France were studied by analysing the chemical forms of these metals and evaluating their phytoavailability. These metals were determined using flame or electrothermal absorption atomic spectrometry （FAAS or ETAAS）, depending on their concentration levels. After optimisation of the ETAAS method, characteristic mass of In in water and aqua regia were 9.9 and 18 pg, respectively, showing the high sensitivity of the analytical Soil contamination by metals from anthropogenic activities （e.g., mining and smelting） is a major concern for the environment and human health. Environmental availability of cadmium （Cd）, lead （Pb）, zinc （Zn）, copper （Cu）, and indium （In） in 27 urban soils located around two former Pb and Zn smelters in Northern France were studied by analysing the chemical forms of these metals and evaluating their phytoavailability. These metals were determined using flame or electrothermal absorption atomic spectrometry （FAAS or ETAAS）, depending on their concentration levels. After optimisation of the ETAAS method, characteristic mass of In in water and aqua regia were 9.9 and 18 pg, respectively, showing the high sensitivity of the analytical procedure. Metal partitioning was conducted using a four-step sequential extraction procedure. The results showed that Cd and Zn were mainly in the acid-extractable and reducible forms in the urban soils studied. In contrast, Pb and In were largely in the reducible fraction. However, in some samples, the amount of In extracted in the residual or exchangeable fraction was higher than that in the reducible fraction. Copper was mainly found in the reducible and residual fractions. A pot experiment was conducted in a glasshouse with seven soils （six contaminated and one uncontaminated） and two plant species, ryegrass and lettuce. The results showed transfer of metals from the contaminated soils to the shoots of ryegrass and the edible part of lettuce. The metal bioconcentration factor was in the order of Cd Cu > In > Zn Pb for lettuce leaves, whereas for ryegrass shoots, three orders were found, Cd > Zn > Cu In > Pb, Cd ≥ In > Zn > Cu Pb, and Zn > Cd > Cu > In > Pb, depending on the physico-chemical properties of the soils, such as pH, cation exchange capacity, carbonates, and organic matter. It was established that the metal toxicity was related to the contamination levels and the physico-chemical properties, including pH, organic matter, and in a lesser extent, Ca, Mg, and phosphorus contents, of the soils. However, it was shown that lettuce could grow on soils having high Cd and CaCO₃ contents. Cadmium was one of the most available metals while Pb was always the least available in the soils studied.     

Mercury content of soils in Western Britain with special reference to contamination from base metal mining

Mercury was determined in 51 soil samples from historic base metal mining areas of England and Wales, together with cadmium, copper, lead, zinc, pH and organic content. Background mercury was calculated as 0.093 ppm whence 51% of the samples were judged to be contaminated. A very strong statistical correlation between mercury and lead and weaker but significant correlations between mercury and copper and zinc were found. Highest levels of mercury (maximum, 1.78 ppm Hg) and other metals occurred in soils derived from the floodplain of a river which was at one time badly polluted by mine waste. In a profile pit near a lead mine in the west of England both mercury and lead were enriched in surface horizons. It is concluded that land contaminated by heavy metals, especially lead, in the historic metal mining areas of England and Wales is also likely to be contaminated by mercury.     

Nitrogen Deposition and Strategies for the Control of Acidification and Eutrophication across Great Britain

It is now recognised that a multi-pollutant, multi-effect approach needsto be adopted to address the range of problems caused by atmosphericpollution. In this paper we use a relatively simple trajectory model (HARM)to explore the coupled behaviour of sulphur dioxide (SO₂),oxides of nitrogen (NO_x) and ammonia (NH₃) andthe possible effects of future reductions in emissions of these pollutantson depositions of S and N across Great Britain. The performance of HARM withrespect to concentrations and depositions of NO_y andNH_x is assessed by comparison with data from nationalmonitoring networks. A range of emissions scenarios are modelled and theeffects of these reductions on critical loads exceedance are explored usingthe critical loads function (CLF), which allows both the acidification andeutrophication effects of S and N deposition to be explored simultaneously.Spatial variations in the reductions of deposition of S and/or N required tomeet critical loads are described. Reductions in emissions of the precursorsof strong acids (SO₂ and NO_x) yield benefits interms of ammonium deposition as a result of their coupled chemistry. Thedevelopment of strategies to control nitrogen deposition will need to take this non-linearity in to account.     

Late Quaternary environmental change inferred from phytoliths and other soil-related proxies: Case studies from the central and southern Great Plains,USA

This study investigates stable carbon isotopes (δ¹³C), opal phytolith assemblages, burnt phytoliths, microscopic charcoal and Sporormiella spores from modern soils and paleosols in Kansas and Oklahoma. Grass and dicot phytoliths in combination with δ¹³C are used as proxies for reconstructing the structure of grasslands and woodlands. Burnt grass phytoliths and microscopic charcoal are evaluated as proxies for reconstructing paleofire incidence. Concentrations of the fungal spore Sporormiella are used as a proxy for assessing large herbivore activity. These proxies were tested on various modern grassland communities of the central and southern Great Plains, including areas with bison, cattle, and small herbivores, and areas under different fire frequencies.     

Mercury dispersal in water,sediments and aquatic biota of a gold mining tailing deposit drainage in pocone,Brazil

In the Pocone district, Brazil, Hg distribution was studied in a small watershed which drains tailings from a 10 yr old gold mining operation. Heavy regional rains are responsible for continuous weathering, thereby making it possible to transport Hg into the ecologically important Pantanal area. Mercury concentrations in creek sediments range from < 0.02 to 0.18 mg. kg^?1. The highest concentrations occur close to the tailings deposit. Mercury concentrations in the water were always below the detection limit of the analytical method used (<0.04 µg. L^?1). Suspended matter samples collected before, during and after a storm, showed a Hg peak value of 0.61 mg kg^?1. about 30 min after the event. Dissolved Hg concentration still fell below the detection limit. Among the biota, molluscs accumulated moderately high concentrations of Hg, while macrophytes and fish did not. Mercury concentrations in molluscs were dependent on size, with larger animals presenting higher Hg concentration. We conclude that Hg present in the tailings shows low mobility and that its eventual transport into the drainage system is dependent on the erosion of fine material from the wastes during rains, resulting in a restricted contamination of the area and low Hg concentration in the biota.