Comparison of subcellular partitioning, distribution, and internal speciation of Cu between Cu-tolerant and naïve populations of Dendrodrilus rubidus Savigny.
When considering contaminated site ecology and ecological risk assessment a key question is whether organisms that appear unaffected by accumulation of contaminants are tolerant or resistant to those contaminants. A population of Dendrodrilus rubidus Savigny earthworms from the Coniston Copper Mines, an area of former Cu mining, exhibit increased tolerance and accumulation of Cu relative to a nearby non-Cu exposed population. Distribution of total Cu between different body parts (posterior, anterior, body wall) of the two populations was determined after a 14 day exposure to 250 mg Cu kg(-1) in Cu-amended soil. Cu concentrations were greater in Coniston earthworms but relative proportions of Cu in different body parts were the same between populations. Cu speciation was determined using extended X-ray absorption fine structure spectroscopy (EXAFS). Cu was coordinated to O atoms in the exposure soil but to S atoms in the earthworms. There was no difference in this speciation between the different earthworm populations. In another experiment earthworms were exposed to a range of Cu concentrations (200-700 mg Cu kg(-1)). Subcellular partitioning of accumulated Cu was determined. Coniston earthworms accumulated more Cu but relative proportions of Cu in the different fractions (cytosol > granular > tissue fragments, cell membranes, and intact cells) were the same between populations. Results suggest that Coniston D. rubidus are able to survive in the Cu-rich Coniston Copper Mines soil through enlargement of the same Cu storage reservoirs that exist in a nearby non-Cu exposed population.
Arnold
Becky E
BE
Department of Soil Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire RG6 6DW, UK.
Hodson
Mark E
ME
Charnock
A John
AJ
Peijnenburg
Willie J G M
WJ
D000818:Animals; D000845:Annelida / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism*
D003300:Copper