Student Research Publications
Intestinal solubilization of particle-associated organic and inorganic mercury as a measure of bioavailability to benthic organisms
Environmental Science & Technology 33:1871-1876
The bioavailability of particle-associated inorganic mercury (Hg-I) and monomethylmercury (MMHg) was evaluated in vitro using digestive fluid of the deposit feeding lugworm, Arenicola marina. Digestive fluid, removed from the midgut of the polychaete, was incubated with contaminated sediment, and the proportion of Hg-I or MMHg solubilized by the digestive fluid was determined. Digestive fluid was found to be a more effective solvent than seawater in solubilizing particle-associated Hg-I and MMHg. A greater percentage of MMHg than Hg-I was solubilized from most sediments, suggesting that sediment-associated MMHg is generally more readily available from sediment for biological uptake. The proportion of MMHg released from the sediment was inversely correlated with sediment organic matter content, decreasing exponentially with increasing organic matter content of the sediment. The results for Hg-I were equivocal. MMHg bioaccumulation factors (BAFs) from previous studies showed a similar trend with organic content of sediment, suggesting that solubilization may be the process limiting the bioaccumulation of particle-bound MMHg. It is concluded that in vitro extraction with a deposit feeder's digestive fluid provides a potential tool to study the process of Hg bioaccumulation via ingestion routes, although its application to various sediments and organisms needs further investigation.