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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 5992

J.E. Morgan and A.J. Morgan; Heavy metal concentrations in the tissues, ingesta and faeces of ecophysiologically different earthworm species. Soil Biol.Biochem. 24(12):1691-1697, 1992

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Concentrations of heavy metals (Pb, Cd, Zn and Cu) were determined in five species of earthworms, representing different ecophysiological groups, sampled from soils associated with an abandoned Pb and Zn mine site. Surface soil-dwelling species (Aporrectodea caliginosa and Allolobophora chlorotica) accumulated significantly greater concentrations of Cd than deep-burrowing (Lumbricus terrestris and Aporrectodea longa) or litter-dwelling (L. rubellus) species. Aporrectodea caliginosa generally accumulated greater concentrations of Pb than other species. The greatest concentrations of Zn were generally found in the deep-burrowing species, whilst lowest concentrations were found in Allolobophora chlorotica. No consistent inter-species pattern was evident for Cu. The composition (metal and organic carbon) of the ingesta of earthworms was different to that of the soil. Concentrations of Cd in the ingesta of Aporrectodea calignosa were significantly greater than in the ingesta of Aporrectodea longa and L. terrestris; concentrations of Pb in the ingesta of Aporrectodea caliginosa and Aporrectodea longa were greater than for L. terrestris. The metal concentrations in the faeces were similar for all species. A significant correlation exists between ingesta and tissue Cd concentrations, but was not evident for Pb or Zn. This suggests that ingested total Cd concentration is a primary factor in determining tissue Cd concentrations of earthworms. For the other metals other interactive factors appear to markedly influence accumulated tissue metal concentrations.