Lead Concentrations In Sediments Research Articles

Ancient mining pollution in early to middle Holocene lake sediments from the Lake Superior region, USA

Determining the timing and transport mechanisms (i.e. fluvial and/or atmospheric) of pollution associated with ancient copper mining on Isle Royale in Lake Superior (United States) is important for understanding the current and future trajectory of ecosystems affected by human activity. This study reports metal concentrations in sediment from two small, closed-basin lakes located on Isle Royale (Lily Lake and Pond 2) as a measure of the extent of heavy metal emissions from Indigenous, precontact mining and annealing activities associated with one of the world’s oldest metal working industries. Lily Lake and Pond 2 are both located near known mines, but neither lake contains mines in its catchment and thus could not have received pollution via fluvial transport. Elevated concentrations of lead in sediments dating to ∼6000 years ago at both lakes provide evidence of atmospheric transport of pollution associated with mining emissions. The age of ∼6000 years before present is consistent with the timing of elevated lead concentrations in sediment from McCargoe Cove on the northern shore of Isle Royale. Collectively, the data indicate that the peak in Archaic Period mining occurred on southwestern Isle Royale ∼6000 years ago and was preceded by periods that varied in intensity and location across the area. The discovery of pollution signals in lake sediments from the Lake Superior region provides clues as to the timing, spatial patterns, and magnitude of one of the world’s earliest large-scale metal mining efforts. These findings provide a basis for determining the transport mechanisms of ancient mining pollution and are a step toward assessing the full environmental impact of mining and metal working efforts by early human civilizations. • Anthropogenic lead was detected in lakes near prehistoric mines on Isle Royale. • The presence of anthropogenic lead indicates airborne pollution transport • The peak of mining and associated pollution occurred ∼6000 years ago. • Findings are consistent with regional sediment records and copper artifact dates.

Lead concentrations in sediments and mollusc gastropod from Vridi Canal, Côte d’Ivoire

Lead (Pb) is one of the most frequent and toxic contaminant in the environment. It can be bioaccumulated by marine organisms through contaminated sediments as well as their food chains. The current study aimed at investigating Pb occurrence in the sediments and gastropod P. haemastostoma from Vridi Canal. Sediment samples were taken using a Van Veen steel grab of 0.02 m2 area, sealed in plastic bags and transported to the laboratory at 4 °C. Gastropod P. haemastostoma species were collected manually using gloves, and then placed in polyethylene plastic bags. The different concentrations were determined using atomic absorption spectrometer Varian AA 20. The results showed seasonal variability of Pb concentrations in sediments and P. haemastostoma. In the both matrices, Pb exhibited the same trend in the distribution between the seasons. This study also mentioned that sediments were highly contaminated by Pb (54.27-134.71 mg/kg). Vridi Canal was found to be one of the most contaminated seaport area. Pb levels (49.55-104.19 mg/kg) in P. haemastostoma exceeding the maximum permitted levels according to the United Nations Food and Agriculture Organization (FAO). This research demonstrated that sediments having lower ecological risk may be resulting in lower tissue Pb of P. haemastostoma.
 Keywords: Metal Pb, sediment, P. haemastostoma, seasonal variation

High bioaccumulation of cadmium and other metals in Patagonian edible gastropods

ABSTRACTHigh concentrations of metals are accumulated by edible marine resources, affecting human health. Marine gastropods have been commercially captured and consumed in Argentina for decades without official regulations or studies to guarantee their safety. In this study, metals (cadmium, aluminium, iron, zinc, copper and lead) were analysed for the first time in the edible marine gastropods Buccinanops globulosus, Adelomelon ancilla and Trophon geversianus and their surrounding sediments. Taking into account the maximum levels recommended by national and international regulations for food safety, we recommend consuming only the foot of these gastropod species. We recommend not consuming these gastropods from harbour areas due to concentrations of lead in sediments and tissues. Though the target hazard quotient (THQ) of cadmium was not high for the local community, it could be higher for other populations who consume molluscs more frequently, indicating a potential health risk of chronic exposure. Monitoring of these and other contaminants should be performed in order to ensure food safety of these marine resources.

Composition of Juvenile Corals on Different Morphotypes of Substrate at Karimunjawa Archipelago, Indonesia

Rapid developments of industry and population growth have lead to ecological pressures on coastal areas. Semarang as capital of Central Java and port city, has an environment sensitivity which is important to be investigated. Sediment is an important part in aquatic environment because acts as sink or source of pollutant and could be used to assess coastal environment health. Three locations had been studied, i.e. Tanjung Mas Port, estuaries of Banjirkanal Barat and Banjirkanal Timur. These locations were compared to assess their health of sediment through elutriate sediment toxicity test. Eighteen grams of sediment from each locations were weighed and placed in 1 L Beaker glass. Eggs and sperm are taken from spawning of adult green mussel in laboratory. Thirty mL of sperm was added to the eggs and fertilized eggs were observed microscopically. Fertilized eggs were exposure to elutriate water-sediment from each location for 48 hour. Statistical analysis showed that there are significantly different abnormalities larvae percentage of sites 5, 8 and 13. The highest percentage of abnormality larvae occurred in Port Tanjung Mas, followed by Banjirkanal Timur and Banjirkanal Barat. Lead concentrations in sediments of coastal Semarang was ranged from 10.9 to 15.62 mg.kg -1 , with an average of 13.69 mg.kg -1 . Lead concentration was decreased form Port, Banjirkanal Timur and Banjirkanal, respectively. The abnormalities of green mussel larva may related to lead contamination. It could be concluded that sediment quality in Port area was very poor compare than other site. Keywords: bioassay , green mussel larvae, sediment, Semarang coastal area

Lead concentration and the content of selected macroelements in lake sediments in Poland

Lead has been used extensively for thousands of years. Once introduced into the environment, like any other heavy metal, lead accumulates in soil and sediments. High lead concentrations in river and lake sediments can be harmful to aquatic organisms. At present, uncontaminated water sediments in the northern and central parts of Poland contain below 9 mg of lead per kg. The lakes located within the following lake districts: Greater Poland, Pomeranian and Masurian, provided 409 samples of surface sediments from deep spots (the profundal zone). All the samples were tested for the content of Pb and other selected macroelements. The content of Ca, Mg, Fe, K, Mn, Na, P, Pb and S was determined by ICP-OES and the total organic carbon (TOC) was evaluated by the coulometric titration method. The observed range of lead concentration was from below 3 to 222 mg kg-1. The average content was 37 mg kg-1, the geometric mean 30 mg kg-1, and the median 33 mg kg-1. In the majority of samples, the lead concentration was higher than the geochemical background. Only in 5.77% of the samples, the lead content was lower than 10 mg kg-1. The lead concentration in the sediments was relatively well correlated with the total organic carbon (r = 0.59), aluminium (r = 0.45) and sulphur (r = 0.47), moderately correlated with iron (r = 0.26) and potassium (r = 0.28), very weakly correlated with phosphorus (r = 0.12) and negatively correlated with the calcium concentration (r = -0.28). No correlation was observed for manganese (r = -0.05), magnesium (r = 0.07) and sodium (r = -0.07). Factor analysis revealed the presence of two factors that together accounted for nearly 45% of variation. The first factor included aluminium, potassium and magnesium, and the second one sulprof. dr hab. Izabela Bojakowska, Polish Geological Institute National Research Institute, 4 Rakowiecka Street, 00-975 Warsaw, Poland, e-mail: izabela.bojakowska@pgi.gov.pl

Determination of Lead in fish, water and sediment

The objective of the study is to determine the concentration of Lead in water, sediment and the marine species, Indo-Pacific king mackerel popularly known as Spotted Seer fish (Scomberomorus Guttus) collected near seashore of Bay of Bengal from 5 locations (Pulicat, Ennore, Marina, Mahabalipuram and Kalpakkam) in North Chennai in 4 different seasons (Summer, Monsoon, Post-Monsoon, and Winter). The concentrations of Lead in each sample were determined using AAS method. Maximum concentrations of Lead in fish samples collected from different locations were 0.563 mg/kg (Pulicat Summer), 0.722 mg/kg (Ennore Summer), 0.616 mg/kg (Marina Monsoon), 0.363 mg/kg (Mahabalipuram Summer) and 0.673 mg/kg (Kalpakkam Post-Monsoon). Maximum concentration of Lead in water samples collected from different locations were 0.016 mg/l (PulicatSummer), 0.015 mg/l (EnnoreMonsoon), 0.012 mg/l (MarinaMonsoon and winter),0.014 mg/l (MahabalipuramMonsoon) and 0.016 mg/l (KalpakkamMonsoon). The maximum concentrations of Lead in sediments collected from different locations were 1.083 mg/kg (PulicatPostmonsoon), 1.481 mg/kg (EnnoreMonsoon), 0.848 mg/kg (MarinaSummer), 1.004 mg/kg (MahabalipuramSummer) and 0.904 mg/kg (KalpakkamPost-monsoon).

Lead from hunting activities and its potential environmental threat to wildlife in a protected wetland in Yucatan, Mexico

This study provides insights into the status of lead in the protected wetland of El Palmar, located on the northwestern littoral of the Yucatan Peninsula. This reserve is ecologically and economically important because it provides feeding and breeding habitats for many species, as well as being an ecotourism destination (especially for bird watching). Although it is a protected area, duck species are heavily hunted within the reserve during the winter. As a result, animals feeding or living in sediments could be exposed to anthropogenic lead. Total lead and its geochemical fractionated forms were measured in sediment cores from six selected sites in “El Palmar” wetland, during pre- and post-hunting seasons, to approximate the potential environmental threat (especially for benthonic living/feeding organisms). Anthropogenic lead concentrations detected in soil cores ranged from below the minimum infaunal community effect level (30.24μgg−1) during the pre-hunting season, to bordering the probable infaunal community effect level (112.18μgg−1) during the post-hunting season, according to SquiiRTs NOAA guidelines. Yet, these results were lower than expected based on the intensity of hunting. Consequently, this article explores the possibility that the lower than expected lead concentration in sediments results from (1) degradation of shot and transformation to soluble or particulate forms; or (2) ingestion of lead shot by benthic and other lacustrine species living in the protected area. Geochemical fractionation of lead demonstrated that in the top 6cm of the soil column at heavily active hunting sites (EP5 and EP6), lead was associated with the lithogenic fraction (average 45 percent) and with the organic fraction (average 20 percent). Bioavailable lead (sum of lead adsorbed to the carbonates, Fe/Mn oxyhydroxides and organic fractions) in sediments was lower than 50 percent for the heavily active hunting areas and higher for the rest of the sites. Multivariate analysis showed that the environmental chemistry, the physicochemical characteristics of the water, and the geochemical qualities of the sediments do not favor the release of lead into the water column. Thus, the direct consumption of lead shot by organisms feeding in sea grass or in the top 10cm of sediment is perhaps the major process preventing lead from being deposited in sediments, and, as such, these species (e.g., flamingos and/or ducks) could be threatened by anthropogenic lead pollution.

Arsenic Cadmium and Lead Concentrations in Sediment and Biota from Songkhla Lake: A Review

This article reviews the existing data on trace elements (Arsenic (As), Cadmium (Cd) and Lead (Pb)) in sediments and biota from Songkhla Lake, a shallow coastal lagoon in Southern of Thailand between 1998 and 2012. At present, the situation of those trace elements in sediments show moderate concentration levels for Cadmium and Lead. High levels for Arsenic have been found in the Outer Section of Songkhla Lake especially at the mouths of Samrong, U-Taphao and Phawong canals. The accumulation of trace elements in fish muscle tissue was well within limits for human consumption.

Geochemical and isotopic characteristics of karstic springs in coastal mountains (Southern Croatia)

Seventeen gravity springs from the slopes of the Biokovo, Sutvid and Rilić Mountains at the Adriatic coast of Croatia were investigated. Five of them are included in the regional and three of them are included in the local water supply system. Other springs are used by local inhabitants and tourists for drinking. The aim of this study was to determine the underground karst connections, source and type of the groundwater defining different hydrochemical facies, the aquifer behavior and the impact of the rehabilitated landfill Donja Gora on karstic springs due to the detected anomalous concentrations of lead in sediments. Hydrochemical facies was determined using a Piper diagram. It was shown that groundwater belongs to the Ca–HCO3 type of water.Concentrations of 17 dissolved and total trace elements, organic compounds, organic carbon, nutrients and ions, phenols, PCBs and mineral oil microbiological properties, physical and chemical indicators were determined in groundwater samples. Their concentrations were extremely low, more than 3 orders of magnitude less than allowed by the Croatian regulations for the first category of groundwater and drinking water, so the quality of water is excellent. Origin of some elements is discussed and complex statistical analysis is performed, using log-probability plots and partitioning of distributions following the Sinclair graphical procedure. Majority of minor and trace element concentrations show unimodal distribution of the data. Only five elements (Al, Mn, Ni, Pb and Zn) show the combinations of 2 or 3 log-normal distributed populations, probably reflecting the presence of different sources and/or processes.For the first time, isotopic investigations were performed in any karst region of Croatia, measuring the concentration of dissolved radon in the groundwater. The measured values of radon concentrations for spring water ranged from 0.45BqL−1 to 16.53BqL−1. These results are much lower than the reference level of 100BqL−1 set by the European Commission for drinking water. The lowest radon concentration 0.44BqL−1 was measured at the surface water intake on the Cetina River.The mass fractions of 16 elements were determined in 3 representative spring sediments. Highest concentrations of some metals in total sediments (mgkg−1, d.w.) are: lead 2601, chromium 244, silver 1.11, manganese 1178, zinc 322, copper 507 and barium 461. Lead concentrations are assumed to be of natural origin.

Lead Concentrations in Sediments and Blue-Winged Teals (Anas discors) From El Palmar State Reserve, Yucatan, Mexico

Reserve regulations at El Palmar State Reserve, Yucatan, Mexico, prohibit the use of lead (Pb) shot, but hunters continue to use it, and no enforcement is implemented. Pb was quantified in sediments and in blue-winged teal Anas discors. No shot pellets were found in the sediment samples, nor were differences in sediment Pb concentrations observed within the reserve between popular hunting sites and those no longer used for hunting. However, there were differences between the hunting sites and sediments from an adjacent area where hunting is prohibited. Average Pb concentrations were highest at hunting entrances (15.69 ± 18.69 mg/kg) and lowest at decoy locations (5.24 ± 4.84 mg/kg). These averages are lower than the lowest effects level (31 mg/kg), although 10 samples exceeded this level. Pb-shot prevalence in gizzards was 4.88% (n = 41). Pb levels exceeded 5.0 mg/kg dry weight in one or more of the tested tissues (liver, gizzard, and bone) in 14 (34.14%; 7 female, 7 male; 11 adult, 3 juvenile) of the total birds. Bird weight, sex, and age had no effect on Pb concentration. Hunting using Pb shot in the reserve clearly affects Pb levels in sediments and in A. discors that winter there.

Sources and risk factors for lead exposure in indigenous children of the Peruvian Amazon, disentangling connections with oil activity

In the Corrientes river basin, Peruvian Amazon, lead exposure among indigenous communities was first reported in 2006. To address controversy regarding the main source of exposure, this study aimed to identify the sources and risk factors for lead exposure among children from the communities in question, and to clarify the potential relationship with oil activity. This cross-sectional study was conducted in six communities. Participants were children aged 0-17 years and their mothers. Data collection included blood lead levels (BLLs) and hemoglobin determination, a questionnaire on risk factors and environmental sampling. We used age-stratified multivariate regression models, with generalized estimating equation to account for correlation within households. Twenty-seven percent of the children had BLLs ≥10 μg/dl. Mother's BLLs ≥10 μg/dl, playing and chewing lead scraps, fishing ≥three times/week, and living in highly oil-exposed communities increased the risk of having BLLs ≥10 μg/dl. Lead concentrations in sediment, soil, dust, and fish samples were below reference values. Mother's BLLs ≥10 μg/dl, playing and chewing lead scraps to manufacture fishing sinkers were the most important risk factors for children's BLLs ≥10 μg/dl. The connection with oil activity appears to be through access to metal lead from the industry's wastes.

Exposure–dose–response of Anadara trapezia to metal contaminated estuarine sediments. 2. Lead spiked sediments

The composition of near shore marine environments is increasingly being altered by contaminants from human activities. The ability of lead, which has no known biological function, to mimic biologically essential metals makes it one of the most toxic to marine biota. The relationship between lead exposure, dose and response was investigated in Anadara trapezia exposed for 56 days to lead spiked sediment (100 and 300μg/g dry mass). Lead tissue concentrations of the 300μg/g exposed A. trapezia doubled in the last 2 weeks of exposure with final lead tissue concentrations of exposed organisms of 1 and 12μg/g, respectively. Tissue lead accumulation of exposed organisms followed the pattern haemolymph>gill>hepatopancreas during much of the 56 day exposure. Between 30 and 69% of accumulated lead in the gill and hepatopancreas was detoxified and fairly evenly distributed between the metal rich granule and the metallothionein like protein fractions. Approximately half of the biologically active lead in both tissues was in the mitochondrial fraction which showed increased cytochrome c oxidase activity in lead exposed organisms. There was a reduction in GPx activity, an associated increase in total glutathione concentrations and reduced GSH:GSSG ratios due to a build up of oxidised glutathione. These changes in the glutathione pathway were reflected in the total antioxidant capacity of lead exposed A. trapezia which were significantly reduced compared to control organisms. Increased lead exposure significantly increased lipid peroxidation, lysosomal destabilisation and frequency of micronuclei. A significant exposure–dose–response relationship for A. trapezia exposed to lead enriched sediments indicates that elevated sediment lead concentrations have the potential to increase biologically active lead burdens and impair the antioxidant reduction capacity leading to a series of associated effects from lipid peroxidation to cellular perturbation and genotoxic damage.

Modelling suspended sediment lead concentrations in contaminated peatland catchments using digital terrain analysis

Upland peat soils in close proximity to urban and industrial areas can be contaminated with high concentrations of atmospherically deposited lead. The peat soils of the Peak District (UK) are characterised by extensive eroding gullies. Fine-resolution digital topographic data were used to map the extent and depth of these gullies. Peat samples from eroding gully walls and suspended sediments were collected and analysed for lead content. Variability in lead concentrations of gully wall material and suspended sediments can be explained by differences in mean upslope gully depth. The lead content of suspended sediment exported from catchments characterised by shallow peat gullies is higher than that exported from catchments with deep peat gullies. The empirical relationship between sediment-associated lead concentration and mean upslope gully depth was combined with the gully depth mapping to produce a predictive spatial model of suspended sediment lead concentrations across the Peak District. This model may be particularly useful for catchment managers who are currently involved in the restoration of eroding peat soils in the Peak District uplands.

Long‐term sediment bioassay of lead toxicity in two generations of the marine amphipod Elasmopus laevis, S.I. Smith, 1873

Sediments are evaluated for toxicity by measuring mortality in a single cohort of amphipods in either acute (10-d) or chronic (28-d) bioassays. This investigation differed from conventional bioassays in four ways: Sublethal effects (fecundity) were estimated; the testing period was 60+ d; two successive generations were examined; and Elasmopus laevis Smith, 1873, amphipods were employed. Four test sediments were created between 58 and 424 microg/g of lead using the 30-microg/g whole-sediment as the control. Bioaccumulated lead at 60 d varied as a linear function of lead concentration in the sediments. Fecundity, as estimated by offspring-per-chamber and/or percent reproductive success, was reduced as sediment lead concentrations increased and reproduction was delayed compared with the control. The reduction in offspring production per test chamber varied significantly as an inverse function of lead sediment concentration, best described by a curvilinear exponential equation. It was concluded that E. laevis exposed to 118 microg/g and higher could not maintain a population as large as that in the control. Although the current sediment quality guideline for lead stipulates that adverse biological effects likely will occur above 218 microg/g, this study revealed a statistically significant negative reproductive response at 118 microg/g lead, and suggests that the current regulatory guideline for lead, based on lethality, should be reconsidered.

Sediment and Suspended Matter Lead Contamination in the Gulf of Kavala, Greece

Sediment and suspended particulate matter samples from 24 stations in the Gulf of Kavala have been examined for lead contamination. Grain size analysis and organic matter content were also performed. Total -- anthropogenic sediment lead concentrations and enrichment factors at stations close to harbors and chemical industries were found higher (up to 209-135 micro g/g and 4.12 respectively), in relation to concentrations from the rest of the coastal zone. In the above areas, increased suspended particulate lead in the bottom of the water column was also recorded (up to 109 micro g/g). Total sediment lead concentrations composed of high natural Pb background increased with decreasing grain size, suggesting their association with the fine fractions of the sediments (31.1-66.0% mud presence) and the organic matter content (6-9% higher values). Overall, higher total lead concentrations in the sediments, determined by this work, appear to be significantly different from those reported for the Gulf of Kavala in previous studies and similar to those detected in other highly contaminated eastern Mediterranean coastal areas.

Lead pollution in a large, prairie-pothole lake (Rush Lake, WI, USA): Effects on abundance and community structure of indigenous sediment bacteria

Rush Lake (WI, USA), the largest prairie-pothole lake east of the Mississippi River, has been contaminated with lead pollution as a result of over 140years of waterfowl hunting. We examined: (1) the extent of lead pollution in Rush Lake sediments and (2) whether lead pollution in Rush Lake is affecting the abundance and community structure of indigenous sediment bacteria. Sediment lead concentrations did not exceed 59mg Pb kg−1 dry sediment. No relationship was observed between sediment lead concentration and the abundance of aerobic (P=0.498) or anaerobic (P=0.416) heterotrophic bacteria. Similarly, lead did not appear to affect bacterial community structure when considering both culturable and nonculturable community members. In contrast, the culturable fraction of sediment bacteria in samples containing 59mg Pb kg−1 exhibited a unique community structure. While factors other than lead content likely play roles in determining bacterial community structure in the sediments of Rush Lake, these data suggest that the culturable fraction of sediment bacterial communities is affected by elevated lead levels.

Concentrations of heavy metals in sediment and organisms during a harmful algal bloom (HAB) at Kun Kaak Bay, Sonora, Mexico

In early April 2003, fishermen from Kino Bay Sonora alerted us about a massive die-off of fish and mollusks occurring at Kun Kaak Bay. Phytoplankton samples taken on 17 May 2003 reported the presence of a harmful algal bloom composed of Chatonella marina, Chatonella cf. ovata, Gymnodinium catenatum and Gymnodinium sanguineum. On 22 of May, we collected samples of water, sediment and organisms at the affected area. Physicochemical parameters and nutrients were measured in water samples from different depths. Sediment and benthic organisms were analyzed for Cd, Cu, Zn, Pb and Hg. We found concentrations of heavy metals higher than background levels for this area. Cadmium and Lead concentrations in sediment from the HAB area were up to 6× greater than background levels and Cd in mollusks was 8× greater than regulations allow. A relationship between elevated Cd and Pb concentrations in sediment and the survival of toxic dinoflagellates is suspected.

Lead pollution and its sources along the Turkish coast of the Black Sea

Lead pollution and its sources have been investigated in the south-eastern and south-western Black Sea. Surficial sediments and mussels were collected in different seasons of the year from the south-eastern and south-western Black Sea and analysed for their lead contents.In the south-eastern Black Sea sediments from the easternmost and from the central stations contained the highest lead concentrations. Sediments contained 8 to 10 times the lead concentrations of sediments from the south-west. Samples taken from rivers, streams and effluents had especially high lead concentrations. The highest lead concentrations were found in sediments collected in October and December.Lead concentrations in mussels from the south-eastern coast were comparatively lower compared to those from the south-western coast. The highest average values occurred in December and in October.In the south-western Black Sea, the highest lead concentrations in sediments were obtained in those from Inebolu, followed by those from around Zonguldak. The concentrations increased from the middle to the west of the southern Black Sea coast, possibly due to the effect of the Danube River. Sediments taken in September had the highest lead concentrations, followed by samples taken in December.Very high lead concentrations (> 10 μ g g-1) were observed in mussels from those stations where the sediments also contained high concentrations. Mussels had their highest lead concentrations in January and April.

Oceanography. Patterns of Arctic circulation.

Pollutants such as lead are transported even to remote regions of the world, where they are deposited in sediments. In his Perspective, Mysak highlights the report by Gobeil et al. , who have studied lead concentration in sediments in the Arctic Ocean. These sediments accumulated over a period of several decades when the high-latitude atmospheric circulation was in a very stable (negative) state and the Atlantic inflow probably did not penetrate very far into the Arctic Basin. The atmospheric circulation has now entered a positive state, in which pollutants entering the ocean from Western Europe are likely to penetrate farther into the Arctic and might even reach the Canadian Basin.

Relation of Waterfowl Poisoning to Sediment Lead Concentrations in the Coeur d'Alene River Basin

For many years, waterfowl have been poisoned by lead after ingesting contaminated sediment in the Coeur d'Alene River Basin, in Idaho. Results of studies on waterfowl experimentally fed this sediment were combined with results from field studies conducted in the Basin to relate sediment lead concentration to injury to waterfowl. The first step in the model estimated exposure as the relation of sediment lead concentration to blood lead concentration in mute swans (Cygnus olor), ingesting 22% sediment in a rice diet. That rate corresponded to the 90th percentile of sediment ingestion estimated from analyses of feces of tundra swans (Olor columbianus) in the Basin. Then, with additional laboratory studies on Canada geese (Branta canadensis) and mallards (Anas platyrhynchos) fed the sediment, we developed the general relation of blood lead to injury in waterfowl. Injury was quantified by blood lead concentrations, ALAD (δ-aminolevulinic acid dehydratase) activity, protoporphyrin concentrations, hemoglobin concentrations, hepatic lead concentrations, and the prevalence of renal nuclear inclusion bodies. Putting the exposure and injury relations together provided a powerful tool for assessing hazards to wildlife in the Basin. The no effect concentration of sediment lead was estimated as 24 mg/kg and the lowest effect level as 530 mg/kg. By combining our exposure equation with data on blood lead concentrations measured in moribund tundra swans in the Basin, we estimated that some mortality would occur at a sediment lead concentration as low as 1800 mg/kg.