Effects of low dosage pyrene pollution on biochemical characters of earthworm (Eisenia fetida) in soil

By the method of artificial soil pollution, an exposure experiment with different concentrations of pyrene (0, 60, 120, 240, 480, 960 microg x kg(-1)) was conducted to determine the cytochrome P450 and MDA contents and the glutathione-S-transferase (GST), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities in earthworm gut after exposure for 1, 3, 7 and 14 days. The results indicated that within the range of test pyrene concentrations, all the biochemical indices tested differed in their sensitivity to pyrene toxicity, among which, P450 content and GST and SOD activities were most sensitive, followed by POD and CAT activities, while MDA content did not show any obvious response. Exposure duration had stronger effects than exposure dosage. In diagnosing the ecotoxicity of soil pollutant, it could be necessary to use a combined multi-time and multi-index diagnostic method to enhance the sensitivity and effectiveness of the indices adopted.