Element content in tissues of four rodent species sampled in the Geysers geothermal steamfield

Liver and kidney tissue samples from four rodent species collected in the Geysers geothermal steamfield of northern California were analyzed for content of 28 elements. Element concentrations in samples from the developed region of the Geysers were compared with samples from undeveloped reference regions to determine the influence of geothermal power development on element content in small mammal tissues. Eight elements (B, Ca, Cu, Mg, Mn, P, Sr, Ti) were enriched in samples from the Geysers, 12 (Ag, Al, Co, Cr, Fe, K, Mo, Na, Ni, Pb, Si, Zn) were decreased within the Geysers, Ba and Li were inconclusive, and six (As, Be, Cd, Hg, Sn, V) were below the minimum analytical limits. The longest-lived species (Neotoma fuscipes) had the greatest occurrence of statistically significant differences in element content. Sites in grassland habitat produced more significant differences in element content than either chaparral or streamside habitats for samples from Peromyscus maniculatus. Peromyscus boylii and P. truei provided additional data, but no distinct advantages for element monitoring. The data indicate regional influences from geothermal power development on element levels in rodent tissues.