Heavy metal and arsenic bioaccumulation in small mammals inhabiting the Anaconda Smelter Superfund Site, Montana

A key component in accurately assessing bioavailability of environmental metals at large National Priority List (NPL) sites is a reduction of uncertainty within exposure estimates. This reduction in uncertainty can be facilitated by collecting empirical data from individual animals inhabiting hazardous waste sites. Site-specific metal bioavailability data are also useful in supporting decisions regarding clean up and demediation, and regulators and scientists also support the use of these data in their exposure assessment models. However, rarely are data available to confirm modeled results. The primary objective of this study was quantifying the site-specific bioavailability and accumulation of heavy metals and arsenic in small mammals inhabiting a metals-contaminated NPL hazardous waste site in southwest Montana

Deer mice (Peromyscus maniculatus) and northern pocket gophers (Thomomys talpoides) inhabiting areas contaminated with a gradient of heavy metals and arsenic were collected from the Anaconda Smelter SuperfUnd Site, Montana, USA. A total of 299 deer mice were collected in 1999 and 2000. Arsenic (As), cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) were determined in blood, kidney, liver, mammary tissue, carcass, and stomach contents and compared to metal levels in the soils across six respective trapping grids established on spontaneously revegetated areas of the site. Among deer mouse stomach contents and tissues, only Zn and Cu were detected with regularity in all tissues. Lead and As were detected primarily in carcass samples, and Cd was detected most frequently in liver and kidney samples. Among all tissues analyzed, there were no differences (p > 0.05) between male and female mice for any of the metals except for Pb. When all mice were grouped by sex, there was a larger (p = 0.0380) proportion of female liver samples with detectable concentrations of Pb compared to males. Differences between adult and nonadult mice were mostly observed for Pb, Cd and As concentrations in kidney, liver and carcass samples.