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Do earthworms impact metal mobility and availability in soil? - A review

Sizmur, Tom, Hodson, Mark E.
Environmental pollution 2009 v.157 no.7 pp. 1981-1989
earthworms, soil pollution, metals, bioavailability, chemical speciation, soil microorganisms, soil pH, dissolved organic carbon
The importance of earthworms to ecosystem functioning has led to many studies on the impacts of metals on earthworms. Far less attention has been paid to the impact that earthworms have on soil metals both in terms of metal mobility and availability. In this review we consider which earthworms have been used in such studies, which soil components have been investigated, which types of soil have been used and what measures of mobility and availability applied. We proceed to review proposed reasons for effects: changes in microbial populations, pH, dissolved organic carbon and metal speciation. The balance of evidence suggests that earthworms increase metal mobility and availability but more studies are required to determine the precise mechanism for this. We review the impact of earthworms on metal mobility and availability and suggest areas for further investigation.