Heavy Metal Accumulation in Small Mammals following Sewage Sludge Application to Forests
- Linda J. Hegstrom * and
- Stephen D. West
The application of sewage sludge to forested land as a fertilizer may result in the transfer of heavy metals from sludge to wildlife. Levels of four heavy metals (Cd, Pb, Zn, and Cu) were measured in livers and kidneys of insectivorous Trowbridge's shrews (Sorex trowbridgii) and shrew-moles (Neurotrichus gibbsii), and granivorous deer mice (Peromyscus maniculatus) from sludge-treated and untreated sites at Charles Lathrop Pack Forest, located near Eatonville, WA. Heavy metal levels were higher in the organs of Trowbridge's shrews from sledge-treated areas than in those from untreated areas. Only Cd was elevated in both organs of the deer mouse. Shrew-moles from sludge-treated sites had higher levels of Cd and Pb, but not Zn or Cu, than those from untreated sites. In general, heavy metal levels in the three species from control sites at Pack Forest were similar to levels found in animals from five other control sites in western Washington. Samples of liver and kidney tissue from Trowbridge's shrews were examined for evidence of heavy metal-induced lesions. Despite the high levels of heavy metals found in Trowbridge's shrews, no lesions were found in their organs.
Copyright © . .