Uptake dynamics of inorganic mercury and methylmercury by the earthworm Pheretima guillemi.
Mercury uptake dynamics in the earthworm Pheretima guillemi, including the dissolved uptake rate constant (ku) from pore-water and assimilation efficiencies (AEs) from mercury-contaminated soil, was quantified in this study. Dissolved uptake rate constants were 0.087 and 0.553 L g(-1) d(-1) for inorganic mercury (IHg) and methylmercury (MeHg), respectively. Assimilation efficiency of IHg in field-contaminated soil was 7.2%, lower than 15.4% of spiked soil. In contrast, MeHg exhibited comparable AEs for both field-contaminated and spiked soil (82.4-87.2%). Within the framework of biodynamic model, we further modelled the exposure pathways (dissolved exposure vs soil ingestion) to source the accumulated mercury in Pheretima guillemi. The model showed that the relative importance of soil ingestion to mercury bioaccumulation depended largely on mercury partitioning coefficients (K(d)), and was also influenced by soil ingestion rate of earthworms. In the examined field-contaminated soil, almost (>99%) accumulated IHg and MeHg was predicted to derive from soil ingestion. Therefore, soil ingestion should be carefully considered when assessing mercury exposure risk to earthworms.
['Dang|Fei|F|', 'Zhao|Jie|J|', 'Zhou|Dongmei|D|']
D000818:Animals D007700:Kinetics D008628:Mercury D008767:Methylmercury Compounds D008954:Models, Biological D008962:Models, Theoretical D009835:Oligochaeta D018570:Risk Assessment D012989:Soil Pollutants
Dynamics Mercury Soil ingestion Organisms Uptake pathways