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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 6090

Wei-chun Ma; Sublethal Toxic Effects of Copper on Growth, Reproduction and Litter Breakdown Activity in the Earthworm Lumbricus rubellus, with Observations on the Influence of Temperature and Soil pH. Environ.Pollut.A 33:207-219, 1984

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The sublethal effects of copper on Lumbricus rubellus Hoffm. have been investigated with respect to growth, cocoon production and litter breakdown activity. The concentrations of Cu in the soil ranged from 13 to 370 mg kg-1. Copper additions to soil caused the greatest decreasing effect on cocoon production. Significant decreases in cocoon production at 2 to 6 weeks (15 degrees C) were found at concentrations in the range of 100 to 150 mgCu kg-1, applied either to a sandy soil or to a sandy loam. Litter breakdown activity responded less sensitively with significant decreases occurring at 150 to 300 mgCu kg-1. Body weight was least affected; significant reduction of body weight gain occurred at concentrations greater than 300 mgCu kg-1, together with the first occurrence of mortality. The copper toxicity observed in the acid sandy soil decreased as the soil pH was adjusted from 4.8 to 7.1. Cocoon production increased and body growth decreased as the temperature increased from 12 to 18 degrees C. Litter breakdown activity at 6 weeks showed an optimum at 15 degrees C. The temperature response remained largely unaltered in Cu-amended soil. The relative effect of copper was generally greater as the temperature decreased. These studies show that copper may seriously affect earthworm populations. They also demonstrate the potential usefulness of L. rubellus as a test species in ecotoxicological evaluation of environmental pollutants in soil.