Bioaccumulation of Total Mercury and Monomethylmercury in the Earthworm Eisenia fetida
Abstract
Bioaccumulation factors (BAFs) for inorganic mercury in earthworms are usually <1; however, factors up to approximately 10 have been reported. Little information is available concerning the bioaccumulation of organic mercury in earthworms from actual contaminated soils and thus there has been uncertainty in the risk characterization phase of ecological risk assessments of mercury-contaminated sites. This study was initiated to determine the rate of uptake and bioaccumulation of total mercury (T-Hg) and monomethylmercury (MMHg) in Eisenia fetida from soils which have been contaminated with mercury for approximately 30 years. The study consisted of a 28-day uptake phase in three mercury-contaminated soils and one soil with background concentrations of mercury followed by a 14-day depuration phase in background soil only. Total mercury concentrations in the study soils ranged from 85 to 11,542 micrograms per kg dry weight soil; MMHg concentrations ranted from 1.12 to 7.35 micrograms per kg dry weight soil. Time to 90% steady states for T-Hg ranged from 36 to 42 days. A steady state did not occur for any of the MMHg exposures during the 42-day study; estimated time to 90% steady state varied from 97 to 192 days. BAFs for T-Hg ranged from 0.6 to 3.3. BAFs for MMHg ranged from 175 to 249. The BAFs for T-Hg and MMHg were larger in earthworms exposed to the lower contaminated soils and smaller in the higher mercury-contaminated soils. The absolute concentrations of T-Hg and MMHg bioaccumulated in E. fetida, however, were higher in the earthworms exposed to the higher mercury soils and lower in the less mercury-contaminated soils.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2006
- Accession Number
- ADA454699
Entities
People
- Daniel J. Fisher
- Dennis T. Burton
- Donald J. Green
- Steven D. Turley
- Tommy R. Shedd