T7 PM Metals and Bioaccumulation
Tuesday, 15 November 2005: 1:50 PM - 5:30 PM in 327-329

(VOI-1117-198945) Metal uptake by earthworms in different soils.

Voigt, A¹, Lanno, R¹, ¹ The Ohio State University, Department of Entomology, Columbus, OH, USA

ABSTRACT- Soil characteristics, such as pH and organic matter content, can influence environmental metal availability, and hence metal bioavailability to terrestrial organisms. Earthworms are important indicator organisms for assessing metal bioavailability in soil systems. Bioaccumulation studies were designed to study metal uptake and depuration kinetics in earthworms (Eisenia andrei) as influenced by soil characteristics. Five soils differing in pH, texture and organic matter content were spiked with As, Cd, Pb, or Zn. Earthworms were exposed to metal spiked soils for 2, 4, 8, 16, 32 or 64 days. To examine the depuration kinetics some earthworms were transferred on day 32 into unspiked soil, and these worms were sampled on day 2, 4, 8, 16, or 32 after the transfer. Estimates for environmental metal availability were based upon metal levels dissolved in different weak salt soil extracts or estimated free metal activities in soil solution. The fractionation procedure of Lanno et al. (2002) was applied to examine the uptake and depuration kinetics of the benign and toxicologically bioavailable metal fractions in earthworms. Total metal body burdens and metal levels in various fractions were determined by ICP-OES. The effects of soil physical and chemical properties on metal bioaccumulation kinetics will be discussed.

Key words: metal, bioaccumulation, earthworm, soil