[Eco-toxicity diagnosis on sediments of petroleum wastewater irrigation channel]

Sediment samples were collected from several sites in the upper, mid and lower reaches of the petroleum wastewater irrigation channel in eastern Shenyang of China, and the concentrations of their Cu, Zn, Pb, Cd and mineral oil were analyzed. The results showed that the pollutants were accumulated in all of sediment samples, with 408-118,300 mg x kg(-1) mineral oil, 17.83-78.53 mg x kg(-1) Cu, 35.76-155.16 mg x kg(-1) Zn, 8.50-31.03 mg x kg(-1) Pb and 0.1-1.0 mg x kg(-1) Cd. The sediments showed an inhibition or stimulation effect on plant root elongation and a lethal and sub-lethal effect on earthworm. The inhibition rate of root elongation based on germination test was -29.81 to 93.8%. During 14 d exposure, the maximum mortality rate of earworm was 100%, and during 14d and 28d exposure, the inhibition rate of its body weight growth was -36.6%-(-)6.08% and -40.4%-6.1%, respectively. The study indicated that a long-term irrigation with petroleum wastewater resulted in the accumulation of pollutants in channel sediments and enhanced eco-toxicity.