Testing of metal bioaccumulation models with measured body burdens in mice

Abstract

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.

Cadmium accumulation in herbivorous and carnivorous small mammals: Meta‐analysis of field data and validation of the bioaccumulation model optimal modeling for ecotoxicological applications

“…Soil-dwelling organisms inhabiting these areas are known to accumulate metals [1,2], and dietary transfer to predators such as shrews and moles has been observed [3,4]. Bioaccumulation studies have demonstrated that metal accumulation in small mammals can vary between the extremes of bioreduction and biomagnification [3][4][5][6][7][8][9], which complicates interpretation of field data and environmental risk assessment of metals.…”

Assessment of mercury concentrations in small mammals collected near Las Vegas, Nevada, USA

“…A literature review located several studies reporting mercury concentrations in liver (Clark et al, 1992;Fortin et al, 2001;Lord et al, 2002;Porcella et al, 2004). Several other metal concentration studies also reported values for the liver (Neithammer et al, 1985;Hegstrom and West, 1989;Ma et al, 1991;Pascoe et al, 1994a;Laurinolli and Bendell-Young, 1996;Peles and Barrett, 1997;Nyangababo, 2001;Torres and Johnson, 2001b;Smith et al, 2002). Desert mammals have developed adaptations for survival in the desert, responding to extreme high and low temperatures, rapid evaporative water loss, and scarcity of water (Al-kahtani et al, 2004).…”