Concentrations of arsenic, cadmium, copper, lead, and nickel were measured in soils, house mice (Mus musculus), and the main food items of this omnivorous mouse to examine the occurrence of these metals in selected components of a seasonal wetland. Soil concentrations of copper, lead, and (in some areas) nickel were elevated, but extractable soil concentrations indicated low bioavailability of metals. Levels of most metals in mice and composited arthropods were consistent with reference site concentrations from other studies. However, copper was found to be particularly mobile within the local ecosystem and accumulated in house mouse carcasses and composited arthropods at substantial levels. Metal residues in Scirpus robustus (alkali bulrush) roots exceeded those in seeds, consistent with patterns of bioaccumulation commonly observed in plants. Uptake and bioaccumulation factors for S. robustus seeds and roots, arthropods, and mouse carcasses and livers are reported. Concentrations of lead and nickel in S. robustus roots exhibited significant linear relationships with levels in soils. Copper levels in S. robustus seeds varied significantly with those in house mouse livers, suggesting that trophic transfer of copper from this food source to mice occurred. However, other spatial patterns of bioaccumulation in S. robustus and house mice relative to soil/seed concentrations were absent. Metal levels in house mice bore no relation to body weight or estimated age.

Estimates of chemical accumulation in prey organisms can contribute considerable uncertainty to predictive ecological risk assessments. Comparing body burdens calculated in food web models with measured tissue concentrations provides essential information about the expected accuracy of risk indices. Estimates of arsenic, cadmium, copper, lead, and nickel body burdens in house mice (Mus musculus) inhabiting a seasonal wetland were generated with two small mammal bioaccumulation models. Published soil-to-small mammal bioaccumulation regression models produced accurate estimates of arsenic and lead body burdens but failed to adequately predict copper and nickel levels in mice. Incorporating conservative prediction intervals in the regression models shows potential for successful applications in screening-level risk assessments. A simple mechanistic cumulative ingestion bioaccumulation model overpredicted lead levels in mice generally by less than one order of magnitude but greatly overpredicted concentrations of arsenic, copper, and nickel. Better estimates of absorption and elimination of ingested metals and knowledge of specific arthropod taxa in house mouse diets are likely to improve the accuracy of the cumulative ingestion model. Applying Monte Carlo simulations to the soil-small mammal regression models generated probabilistic estimates of body burdens that were consistent with deterministic results. However, deterministic minimum and maximum predictions of the ingestion model were excessively conservative (widely spaced) relative to lower and upper probabilistic percentiles. Metal levels predicted in individual mice on the basis of mouse-specific parameter values and exposures were not significantly more accurate than bioaccumulation predictions for the sitewide population.

Concentrations of arsenic, cadmium, copper, lead, and nickel were measured in soils, house mice (Mus musculus), and the main food items of this omnivorous mouse to examine the occurrence of these metals in selected components of a seasonal wetland. Soil concentrations of copper, lead, and (in some areas) nickel were elevated, but extractable soil concentrations indicated low bioavailability of metals. Levels of most metals in mice and composited arthropods were consistent with reference site concentrations from other studies. However, copper was found to be particularly mobile within the local ecosystem and accumulated in house mouse carcasses and composited arthropods at substantial levels. Metal residues in Scirpus robustus (alkali bulrush) roots exceeded those in seeds, consistent with patterns of bioaccumulation commonly observed in plants. Uptake and bioaccumulation factors for S. robustus seeds and roots, arthropods, and mouse carcasses and livers are reported. Concentrations of lead and nickel in S. robustus roots exhibited significant linear relationships with levels in soils. Copper levels in S. robustus seeds varied significantly with those in house mouse livers, suggesting that trophic transfer of copper from this food source to mice occurred. However, other spatial patterns of bioaccumulation in S. robustus and house mice relative to soil/seed concentrations were absent. Metal levels in house mice bore no relation to body weight or estimated age.

Estimates of chemical accumulation in prey organisms can contribute considerable uncertainty to predictive ecological risk assessments. Comparing body burdens calculated in food web models with measured tissue concentrations provides essential information about the expected accuracy of risk indices. Estimates of arsenic, cadmium, copper, lead, and nickel body burdens in house mice (Mus musculus) inhabiting a seasonal wetland were generated with two small mammal bioaccumulation models. Published soil-to-small mammal bioaccumulation regression models produced accurate estimates of arsenic and lead body burdens but failed to adequately predict copper and nickel levels in mice. Incorporating conservative prediction intervals in the regression models shows potential for successful applications in screening-level risk assessments. A simple mechanistic cumulative ingestion bioaccumulation model overpredicted lead levels in mice generally by less than one order of magnitude but greatly overpredicted concentrations of arsenic, copper, and nickel. Better estimates of absorption and elimination of ingested metals and knowledge of specific arthropod taxa in house mouse diets are likely to improve the accuracy of the cumulative ingestion model. Applying Monte Carlo simulations to the soil-small mammal regression models generated probabilistic estimates of body burdens that were consistent with deterministic results. However, deterministic minimum and maximum predictions of the ingestion model were excessively conservative (widely spaced) relative to lower and upper probabilistic percentiles. Metal levels predicted in individual mice on the basis of mouse-specific parameter values and exposures were not significantly more accurate than bioaccumulation predictions for the sitewide population.