Impact of triphenyltin acetate in microcosms simulating floodplain lakes. II. Comparison of species sensitivity distributions between laboratory and semi-field

The study objectives were to shed light on the types of freshwater organism that are sensitive to triphenyltin acetate (TPT) and to compare the laboratory and microcosm sensitivities of the invertebrate community. The responses of a wide array of freshwater taxa (including invertebrates, phytoplankton and macrophytes) from acute laboratory Single Species Tests (SST) were compared with the concentration–response relationships of aquatic populations in two types of freshwater microcosms. Representatives of several taxonomic groups of invertebrates, and several phytoplankton and vascular plant species proved to be sensitive to TPT, illustrating its diverse modes of toxic action. Statistically calculated ecological risk thresholds (HC₅ values) based on 96 h laboratory EC₅₀ values for invertebrates were 1.3 μg/l, while these values on the basis of microcosm-Species Sensitivity Distributions (SSD) for invertebrates in sampling weeks 2–8 after TPT treatment ranged from 0.2 to 0.6 μg/l based on nominal peak concentrations. Responses observed in the microcosms did not differ between system types and sampling dates, indicating that ecological threshold levels are not affected by different community structures including taxa sensitive to TPT. The laboratory-derived invertebrate SSD curve was less sensitive than the curves from the microcosms. Possible explanations for the more sensitive field response are delayed effects and/or additional chronic exposure via the food chain in the microcosms.     

Assessment of Sediment Ecotoxicity and Genotoxicity in Freshwater Laboratory Microcosms

One possible fate of dredged sediments is disposal in a submerged gravel pit, but this practice may be a source of contamination of the aquatic environment. In an attempt to assess the risks for the aquatic ecosystem, a microcosm test was conducted in the laboratory on three sediments of channel sections to be dredged. After a 3-day period of stabilization, pelagic organisms (microalgae, daphnids, duckweeds, pond snails) and benthic organisms (amphipods, chironomids) were introduced into microcosms. Survival and growth of organisms were monitored during 28 days. Genetic damage was measured weekly in pond snail hemocytes through the comet assay. The sediments contained high levels of metals (up to 740 mg copper/kg and 1220 mg zinc/kg), but were moderately contaminated by PAHs (total PAH content < 10 mg/kg) and PCBs (total PCB content < 0.6 mg/kg). Only moderate effects on the biota were observed, except for genetic damage on pond snail hemocytes which was significant in all microcosms. The absence of pronounced toxic effects on organisms was not expected since concentrations of some sediment toxicants were above threshold values reported in the literature, especially for metals in two sediments, and for PAHs in the three sediments. Speciation, influence of organic matter and presence of sulfides might explain the low toxicity observed. By contrast, assessment of DNA damage revealed to be more sensitive and enabled a ranking of sediments coherent with their toxic load. In the present work, the microcosm protocol previously set up with a formulated sediment appears to be fitted to natural sediments.     

Structure and function of copper-stressed aquatic microcosms

Laboratory aquatic microcosms were established using natural pond sediment and the organisms contained therein. After a 30-day development time, microcosms were exposed on a flow-through basis to six concentrations of copper with six replicates of each concentration. Measures of energy fixation, material cycling, and biological structure were measured periodically over a 32-wk period.Exposure to copper at 9.3 μg/l and higher resulted in a change in the structure and function of the test systems while 4.0 μg/l did not cause an effect relative to controls. Systems at 9.3 μg/l were structurally similar to controls but at reduced levels of primary production, dissolved organic carbon production, and macroalgal growth. Substantial structural changes occurred at ≥ 30 μg/l as these systems increasingly shifted from autotrophic to heterotrophic systems. Little evidence of adaptation to the copper stress occurred during the test period.     

Response of laboratory ecosystems to environmental stress: Effect of phenol

Ecologically realistic laboratory and field simulated ecosystems (microcosms and mesocosms) are playing increasing roles in fate and effect testing of chemicals and mixtures. Controlled ecosystems allow evaluation of toxicant effects on collective and emergent ecosystem properties. Information is needed to evaluate the validity of test system responses, interpretability of results, and cost effectiveness of simulated ecosystem tests. We developed replicate microcosms using periphyton on polyurethane artificial substrates. Source communities were obtained from two ecosystems—a reservoir in Kentucky and a softwater pond in Virginia—and tested for effects of continuous inputs of phenol (up to 30 mg/L) over 21 days. System responses measured included several biomass estimators, net oxygen production, and protozoan species richness. Communities were generally insensitive to phenol input. Primary production in microcosms from both ecosystems was inhibited at phenol concentrations >10 mg/L and chlorophyll a concentrations were also depressed. Other biomass estimators (protein, hexosamine) were not affected or were stimulated at lower (?10 mg/L) phenol concentrations. Protozoan species numbers were not affected. Functional shifts in the communities preceded adverse structural effects. Effect levels were similar for both communities, although the more complex community with greater biomass (Kentucky) showed more significant responses than the simpler community (Virginia). Systems showed resistance to phenol levels that were actually toxic in standard single-species tests, suggesting that ecosystems may differ in magnitude and rate of response to some nonpersistent toxicants.     

Predicting toxicity in marine sediment in Taranto Gulf (Ionian Sea,Southern Italy) using Sediment Quality Guidelines and a battery bioassay

The goal of this study was to assess coastal marine pollution in the Mar Piccolo and Taranto Gulf (Ionian Sea, Southern Italy) by combining chemical and toxicological data in order to compare and integrate both approaches. Pollutants levels, traditionally, have limited ability to predict adverse effects on living resources. Moreover, in order to provide information on the ecological impact of sediment contamination on aquatic biota Numerical Sediment Quality Guidelines (SQGs) and sediment toxicity bioassays were carefully recommended. In this study ERL (effect range low)/ERM (effect range medium value) and TEL (threshold effect level)/PEL (probable effect level) guidelines have been used. Bioassays were performed with two species of amphipods Gammarus aequicauda and Corophium insidiosum, one species of isopod Idotea baltica and bivalve Mytilus galloprovincialis larvae. The TEL/PEL analysis suggested that, especially for stations 1 and 2, sediments in Mar Piccolo should contain acutely toxic concentrations of metals. In particular Hg content, in station 1, was about 17 times PEL value. 96 h LC₅₀ and 48 h EC₅₀ values were estimated for cadmium, copper and mercury in these species using the static acute toxicity test. M. galloprovincialis larvae was more sensitive than other species to all the reference toxicants tested (EC₅₀ determined for cadmium copper and mercury were of 0.59, 0.11 and 0.01 mg/l respectively). Significant differences in sensitivity of species tested to all reference toxicants (ANOVA p < 0.001) were recorded. Bioassays with these species allowed to estimated sediment toxicity from the different studied sites. On the basis of results obtained a good agreement was reported between chemical data and response of the biological endpoints tested.     

Responses of benthic fish exposed to contaminants in outdoor microcosms--examining the ecological relevance of previous laboratory toxicity tests

Previous laboratory studies indicate that coal combustion wastes (a mixture composed of fly ash and other lower volume wastes such as bottom ash; hereafter collectively referred to as ash) adversely affect the health of benthic fish (Erimyzon sucetta; lake chubsucker), but fish in these studies were provided with ample uncontaminated food resources. Because aquatic disposal of ash can also adversely affect food resources for benthic fish, we hypothesized that changes in resources might exacerbate the effects of ash on fish observed in laboratory studies. We exposed juvenile E. sucetta in outdoor microcosms to water, sediment, and benthic resources from an ash-contaminated site or a reference site for 45 days and compared our findings to previous laboratory studies. Benthic invertebrate biomass was nearly three times greater in controls compared to ash microcosms. Total organic content of control sediment (41%) was also greater than in ash sediments (17%), suggesting that additional benthic resources may have also been limited in ash microcosms. Benthic invertebrates isolated from the ash microcosms had trace element concentrations (As, Cd, Co, Cr, Cs, Se, Sr, and V) up to 18 times higher than in weathered ash used in laboratory studies. The concentrations of trace elements accumulated by fish reflected the high dietary concentrations encountered in the ash microcosms and were associated with reduced growth (final mass = 0.07 g) and survival (25%) compared to controls (0.37 g and 67%, respectively). Accumulation of trace elements, as well as reductions in growth and survival, were more pronounced than in previous laboratory studies, suggesting that resource conditions may be important in mediating ash toxicity. Taken together, our studies suggest that ash discharge into aquatic systems is a more serious threat to the health of benthic fish than previously predicted based upon laboratory toxicity tests.     

Biological effects of marine contaminated sediments on Sparus aurata juveniles

Chemical analysis of the compounds present in sediment, although informative, often is not indicative of the downstream biological effects that these contaminants exert on resident aquatic organisms. More direct molecular methods are needed to determine if marine life is affected by exposure to sediments. In this study, we used an aquatic multi-species microarray and q-PCR to investigate the effects on gene expression in juvenile sea bream (Sparus aurata) of two contaminated sediments defined as sediment 1 and 2, respectively, from marine areas in Northern Italy. Both sediments affected gene expression as evidenced by aquatic multi-species microarray analysis and q-PCR. Exposure of S. aurata juveniles to sediment 1 and sediment 2 altered expression of genes that are biomarkers for endocrine disruption. There were differences between the effects of sediment 1 and sediment 2 on gene expression in S. aurata juveniles indicating that the chemicals in the two sediments had different physiological targets. These results suggest that the classification of sediment solely on the basis of specific chemical profiles is inadequate, and not a true indicator of its potential to cause harmful effects. Our data also indicate that integration of physiochemical analysis and bioassays for monitoring the downstream harmful effects on aquatic organisms are required to gain a complete understanding of the effects of sediment on aquatic life.     

Ecotoxicological evaluation for the screening of areas polluted by mining activities

The aim of this study was to evaluate the applicability of three bioassays representing multiple trophic levels, for the preliminary ecotoxicological screening of sediments from sites contaminated by mining activities. Of the bioassays used in this study, the ostracod test was the most responsive. Vibrio fischeri luminiscence inhibition assay was less sensitive to the toxicants in the sediments than the phytotoxicity assays. The general trend observed was an increase in toxicity values measured by the bioassays with increasing metal mobilization in sediment samples. Therefore, the test battery can be used as a rapid and sensitive tool to evaluate the heavy metal contamination in sediments.     

Pyrene toxicity is affected by the nutrient status of a marine sediment community: Implications for risk assessment

Risk assessment of toxicants often disregards that environmental conditions, like changing nutrient status, may affect ecosystem response to a toxicant even within an ecosystem. We investigated if effects of pyrene on shallow-water sediments depended on nutrient status of the sediment during 58 days of incubation. Natural undisturbed sediment cores were pre-exposed to two concentrations of inorganic nutrients (nitrogen and phosphorous) for 14 days. After terminating nutrient additions, pyrene was applied once to half the Nu_high and half the Nu_low cores in a concentration of 2 mg/kg DW, normalized to 1% TOC. Pyrene affected the sediment systems in both Nu_high and Nu_low, but effects of pyrene differed between nutrient regimes. In the Nu_low system, effects of pyrene were mainly seen on the sediment community structure, such as meiofauna community structure. On the contrary, effects of pyrene in Nu_high were mainly seen on community functions, such as changes in inorganic nutrient fluxes. Direct and indirect effects of pyrene were observed in both nutrient regimes, but they operated on different timescales depending on the variable in focus. This study shows the need to include environmental factors such as nutrient status in risk assessment of toxicants.     

Bioassay assessment of impacts of tar sands extraction operations

This report describes the application of ten bioassays (battery of tests approach) to waters and sediments collected from the tar sands area of northern Alberta, Canada. In this study there were three main goals: (1) to establish the presence and sources of toxicants in these northern waters and sediments, (2) to determine if their presence is related to sediment composition, and (3) to establish which of the various sediment extracting procedures used was most efficient in producing responses in the bioassays used. Results of these investigations indicated that there were two obvious sources of toxicants/genotoxicants, the tar sands extracting area and streams passing through tar sands or oil shales and at least two unknown sources. Based on the techniques used in this study, there does not appear to be a strong sediment structure–toxicant response relationship. Extraction procedure results were variable and are discussed in detail in the report. © by John Wiley & Sons, Inc.     

Sediment Toxicity Bioassays for Assessment of Contaminated Sites in the Nervion River (Northern Spain). 2. Tubifex tubifex Reproduction Sediment Bioassay

Toxicity assessment based on sediment chronic bioassays with the aquatic worm Tubifex tubifex was performed at ten contaminated sites in the industrial area of Bilbao (Northern Spain). One control and three reference sites were also included. Tubifex bioassay measures both survival and reproduction impairment. These endpoints have been contrasted and discussed in relation to somatic growth and both individual and total biomass of cocoons. Survival was only affected at one site which was heavily contaminated by organic compounds, mainly PAHs. A group of four severely ecotoxic sediments was characterised by a drastic reduction in number and size of cocoons, and adult somatic growth. In other group of sediments, some significant increases were found for these variables. It is suggested that these increases represent an effect of hormesis. An index of reproductive effort was used to integrate the relationship between somatic growth and reproduction. Values of reproductive effort at the test sediments were lower than those at the control sediment, suggesting a conservative strategy of oligochaete worms which consisted in an investment into somatic line (growth) at the expenses of offspring. Rates of food consumption which were estimated from egestion rates, were low at the contaminated sites. This fact could be related to the low production levels found at these sites and may reflect avoidance feeding behaviour of the oligochaete worms within the sediments. At some reference sites, high production could have resulted from high nutritional quality of sediments, or to an hormetic effect due to low concentration of some chemicals. Results are discussed in relation to toxicity data from sediment three-brood bioassay with Daphnia magna Straus performed separately on the same sediments.     

Ecotoxicity testing of heavy metals using methods of sediment microbiology

Current measures of microbe-mediated biogeochemical processes in sediments were examined for their potential use as indicators of heavy metal ecotoxicity in both river sediments and bacterial cultures. Assays were carried out with HgCl₂, CuSO₄, and 3CdSO₄ · 8H₂O added to sediment samples and bacterial cell suspensions at concentrations ranging from 0.1 to 10 mM and 0.1 μM to 1 mM, respectively. Chemoautotrophic CO₂ fixation by Elbe River sediment microbiota was most sensitive to Hg²⁺ and Cd²⁺, but not to Cu²⁺. Among the estimates of heterotrophic productivity, incorporation of leucine into cellular protein showed clearer dose responses than incorporation of thymidine into bacterial DNA. Thymidine incorporation was highly resistant to and even stimulated by metal ions, particularly in starved and anaerobic cultures of a test strain of Vibrio anguillarum. Similar metal ion induced “overshoot” responses beyond the levels of untreated controls were noted for mineralization of ¹⁴C-glucose by V. anguillarum and, in the case of Cd²⁺, also in sediment. As a less complex measure of microbial respiratory activity, succinate dehydrogenase (SDH) showed normal dose responses without stimulatory effects, as long as bacterial cell homogenates were assayed. Despite this result, it is concluded that levels of SDH in natural sediment microbiota are inevitably affected by metal-induced processes of selection and enzyme synthesis, and would thus fail to provide an appropriate measure of metal ecotoxicity. The final conclusion is that current parameters of microbial production and activity often reveal dose responses that do not fulfill basic requirements of ecotoxicity testing in metal-polluted sediments. © 1993 John Wiley & Sons, Inc.     

Integrated ecotoxicological assessment of marine sediments affected by land-based marine fish farm effluents: physicochemical, acute toxicity and benthic community analyses

An integrated ecotoxicological assessment of marine sediments affected by land-based marine fish farm effluents was developed using physicochemical and benthic community structure analyses and standardised laboratory bioassays with bacteria (Vibrio fischeri), amphipods (Ampelisca brevicornis) and sea urchin larvae (Paracentrotus lividus). Intertidal sediment samples were collected at five sites of the Rio San Pedro (RSP) creek, from the aquaculture effluent to a clean site. The effective concentration (EC₅₀) from bacterial bioluminescence and A. brevicornis survival on whole sediments and P. lividus larval developmental success on sediment elutriates were assessed. Numbers of species, abundance and Shannon diversity were the biodiversity indicators measured in benthic fauna of sediment samples. In parallel, redox potential, pH, organic matter and metal levels (Cd, Cu, Ni, Pb and Zn) in the sediment and dissolved oxygen in the interstitial water were measured in situ. Water and sediment physicochemical analysis revealed the exhibition of a spatial gradient in the RSP, evidenced by hypoxia/anoxia, reduced and acidic conditions, high organic enrichment and metal concentrations at the most contaminated sites. Whereas, the benthic fauna biodiversity decreased the bioassays depicted decreases in EC₅₀, A. brevicornis survival, P. lividus larval success at sampling sites closer to the studied fish farms. This study demonstrates that the sediments polluted by fish farm effluents may lead to alterations of the biodiversity of the exposed organisms.     

Ecotoxicity assessment of the aquatic environment around Lake Kojima,Japan

To reduce the impact of chemical substances on the aquatic ecosystem, it is essential to understand their ecotoxicological properties in the natural aquatic environment. Consequently, we conducted an ecotoxicological study on the aquatic environment around Lake Kojima, a man-made lake located in the southwest of Japan. Lake Kojima receives its chemical inputs mainly from two rivers that flow through various agricultural and industrial areas. For ecotoxicity screening, surface water and sediment samples were collected 4 times in 1993 from 16 preselected sites. Then, the solutes in the filtered surface water were concentrated by ODS resin, and the organic chemicals in the suspended solids (SS) and sediments were extracted by acetone. A battery of five ecotoxicity tests (agar plate test using bacteria and yeast, algal growth inhibition test, Daphnia magna immobilization test, and root elongation test using lettuce seeds) was used to assess these extracts. The results show that the surface water extracts had a lethal effect on D. magna, the SS extracts suppressed algal growth, and the sediment extracts were inhibitory to the growth of yeast. A significant inhibitory effect by the sediment extracts from 4 lake sites and 3 river sites was detected by these ecotoxicity tests. Attempts also were made to identify the putative ecotoxic chemicals in the collected samples. Elementary sulfur was identified as one of the major toxicants in the sediment extracts that were inhibitory to the yeast growth. Moreover, samples of surface water around Lake Kojima, collected weekly from June to September in 1994, were found to contain three pesticides and were toxic to D. magna. But the concentration of the pesticides detected was too low to cause daphnia immobilization. It is believed that the toxicity of the water extracts was mainly due to the combined toxic effect of natural and man-made components. © 1996 by John Wiley & Sons, Inc.     

Organotins in zebra mussels (Dreissena polymorpha) and sediments of the Quebec City Harbour area of the St. Lawrence River

Toxic antifouling agents such as tributyltin (TBT) and triphenyltin (TPT) have been released in aquatic ecosystems through the use of antifouling paint applied to ship hulls, pleasure crafts and fish nets and these compounds can bioaccumulate in aquatic organisms. The purpose of this study was 1) to assess the extent of the distribution of organotins from a contaminated marina to the St. Lawrence River system by measuring organotin concentrations in zebra mussels (Dreissena polymorpha) and in sediments collected from 9 sites along the St. Lawrence River near Quebec City in July 1998, and 2) to examine the histopathological condition of zebra mussel tissues from these sites. TBT concentrations in zebra mussels were between 37 and 1078 ng Sn g(-1) wet weight, with the highest value found in the Bassin Louise marina. Elevated concentrations were also found in two other marinas. The concentrations decreased sharply to background levels just outside the marinas. All butyltins were detected in all sediments analysed, with highest values found in the Bassin Louise marina. Phenyltins were detected in three of the nine sites in low concentrations (<55 ng Sn g(-1)) in zebra mussels. There was a significant correlation between TBT in sediments and mussels. Gonadal development of zebra mussels varied largely between sites, and was negatively associated to TBT levels in mussel tissue. This study shows that TBT contamination remains a problem in localised freshwater sectors of the St. Lawrence River.     

Histopathological alterations in the liver of the sharptooth catfish Clarias gariepinus from polluted aquatic systems in South Africa

There is a need for sensitive bio-monitoring tools in toxicant impact assessment to indicate the effect of toxicants on fish health in polluted aquatic ecosystems. Histopathological assessment of fish tissue allows for early warning signs of disease and detection of long-term injury in cells, tissues, or organs. The aim of this study was to assess the degree of histopathological alterations in the liver of C. gariepinus from two dams in an urban nature reserve, (Gauteng, South Africa). Two dams (Dam 1 and Dam 2) were chosen for their suspected levels of toxicants. Water and sediments were sampled for metal and potential endocrine disrupting chemical analysis. A quantitative and qualitative histology-based health assessment protocol was employed to determine the adverse health effects in fish. The analysis of blood constituents, fish necropsy, calculation of condition factors, and hepatosomatic indices were employed to support the findings of the qualitative and quantitative histological assessment of liver tissue. Assessment of the liver tissue revealed marked histopathological alterations including: structural alterations (hepatic cord disarray) affecting 27% of field specimens; plasma alterations (granular degeneration 98% and fatty degeneration 25%) of hepatocytes; an increase in melanomacrophage centers (32%); hepatocyte nuclear alterations (90%); and necrosis of liver tissue (14%). The quantitative histological assessment indicated that livers of fish collected from Dam 1 were more affected than the fish livers collected from Dam 2.     

The Importance of Lake Sediments as a Pathway for Microcystin Dynamics in Shallow Eutrophic Lakes

Microcystins are toxins produced by cyanobacteria. They occur in aquatic systems across the world and their occurrence is expected to increase in frequency and magnitude. As microcystins are hazardous to humans and animals, it is essential to understand their fate in aquatic systems in order to control health risks. While the occurrence of microcystins in sediments has been widely reported, the factors influencing their occurrence, variability, and spatial distribution are not yet well understood. Especially in shallow lakes, which often develop large cyanobacterial blooms, the spatial variability of toxins in the sediments is a complex interplay between the spatial distribution of toxin producing cyanobacteria, local biological, physical and chemical processes, and the re-distribution of toxins in sediments through wind mixing. In this study, microcystin occurrence in lake sediment, and their relationship with biological and physicochemical variables were investigated in a shallow, eutrophic lake over five months. We found no significant difference in cyanobacterial biomass, temperature, pH, and salinity between the surface water and the water directly overlying the sediment (hereafter ‘overlying water’), indicating that the water column was well mixed. Microcystins were detected in all sediment samples, with concentrations ranging from 0.06 to 0.78 µg equivalent microcystin-LR/g sediments (dry mass). Microcystin concentration and cyanobacterial biomass in the sediment was different between sites in three out of five months, indicating that the spatial distribution was a complex interaction between local and mixing processes. A combination of total microcystins in the water, depth integrated cyanobacterial biomass in the water, cyanobacterial biomass in the sediment, and pH explained only 21.1% of the spatial variability of microcystins in the sediments. A more in-depth analysis that included variables representative of processes on smaller vertical or local scales, such as cyanobacterial biomass in the different layers and the two fractions of microcystins, increased the explained variability to 51.7%. This highlights that even in a well-mixed lake, local processes are important drivers of toxin variability. The present study emphasises the role of the interaction between water and sediments in the distribution of microcystins in aquatic systems as an important pathway which deserves further consideration.     

Use of protozoan communities to assess the ecotoxicological hazard of contaminated sediments

Protozoan communities developed on artificial substrates were used in a series of in situ and laboratory tests to evaluate the toxic potential of harbor sediments contaminated with polychlorinated biphenyl (PCB). Colonization dynamics in polluted and clean harbors were compared. Laboratory tests were community bioassays using standard techniques to produce sediment elutriate. Results of the in situ colonization and the community tests measuring structural changes (e.g., “decolonization”) were similar. In general, sediments from the contaminated harbor caused significant (p ? 0.05) reductions in the number of taxa, in total protozoan abundance, and in phototroph abundance; however, the abundance of heterotrophic species increased in some in situ tests. Process-level parameters (e.g., respiration; island-epicenter colonization rates) were more sensitive than measurements of community structure. Phototrophs were more sensitive to sediment elutriate than were other trophic types. The information provided by this series of protozoan community tests is more complex than that provided by single-species bioassays. Although community tests may provide more information on the effects of sediment contamination on actual ecosystems than tests based on single species, they require careful interpretation to avoid misleading conclusions.     

Effects of lead-contaminated sediment and nutrition on mallard duckling behavior and growth

Sediment ingestion has become a recognized exposure route for toxicants in waterfowl. The effects of lead-contaminated sediment from the Coeur d'Alene River Basin (CDARB) in Idaho were evaluated on mallard (Anas platyryhnchos) duckling behavior and growth over a 5-wk period using time-activity budgets. Day-old ducklings received either a clean sediment (24%) supplemented control diet, CDARB sediment (3449 microg/g lead) supplemented diets at 12% or 24%, or a positive control diet (24% clean sediment with equivalent lead acetate to the 24% CDARB diet). Ten different behaviors were recorded for nine ducklings per treatment as time spent: resting, standing, moving, drinking, dabbling, feeding, pecking, preening, bathing, and swimming. Contaminated sediment (24% CDARB) and lead acetate significantly decreased the proportion of time spent swimming. There were also problems with balance and mobility in the 24% CDARB and the lead acetate groups. With a less optimal diet (mixture of two-thirds corn and one-third standard diet) containing 24% clean sediment, nutrient level alone affected 6 different behaviors: feeding, pecking, swimming, preening, standing, and dabbling. Nutrient level also significantly decreased the growth rate and delayed the initial time of molt. When the corn diet contained CDARB sediment, the proportion of time spent bathing in the 24% CDARB group significantly decreased. There were also instances of imbalance with 24% CDARB and corn diet, and duckling weights were significantly lower than in corn diet controls. The decreased amounts of time spent swimming or bathing, coupled with problems of balance and mobility, decreased growth, histopathological lesions, and altered brain biochemistry (reported elsewhere), illustrate a potential threat to the survival of ducklings in the wild that are exposed to lead-containing sediments within the CDARB or elsewhere.