SHORT-TERM OXIDATIVE STRESS RESPONSES IN CYPHODERUS JAVANUS BORNER (COLLEMBOLA), AS BIOMARKERS OF HEAVY METAL POLLUTION IN LATERITIC SOILATREYEE SAHANA, SOUMIK AGARWAL, SHELLEY BHATTACHARYA AND JOY VADAKEPURAM CHACKOAbstract The scope of ecotoxicological evaluation of heavy metal pollution in soil was tested from the oxidative stress responses in a detritivore microarthropod species Cyphoderus javanus Borner (Collembola: Insecta) exposed to sub-lethal levels of cadmium and lead treated lateritic soil in microcosms. Chronic toxicity of cadmium was higher than lead on life history parameters of 10- day-old stock of C. javanus (mortality increased by 62% and 27%, moulting declined by 69% and 45%, and fecundity decreased by 97% and 41%, respectively, over the controls, at 200 mg cadmium sulphate / lead acetate kg-1 soil, in 16 days). In contrast, oxidative stress effects were evident within 7 days for both metals at 200 mg kg-1 lateritic soil or river sand. Levels of thio-barbituric acid reactive substances and hydrogen peroxide increased in whole body homogenate, but glutathione content and glutathione-S-transferase activity decreased. Similar trends of stress in soil and sand suggested that toxicity was produced by the exposed metal content in the matrix. Therefore, shortterm oxidative stress responses in C. javanus are potential biomarkers, and a new approach for monitoring heavy metal pollution in soil.
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