Toxicity assessment for chlorpyrifos-contaminated soil with three different earthworm test methods.
Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels (behavior, sublethal, lethal). In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints (acute, chronic, behavioral). Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects at concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.
Zhou
Shi-Ping
SP
Laboratory for Conservation and Utilization of Bio-Resource and School of Life Science, Yunnan University, Kunming 650091, China. kmzhoushiping@163.com
Duan
Chang-Qun
CQ
Fu
Hui
H
Chen
Yu-Hui
YH
Wang
Xue-Hua
XH
Yu
Ze-Fen
ZF
D000818:Animals; D001362:Avoidance Learning; D001522:Behavior, Animal / Q000187:drug effects; D004390:Chlorpyrifos / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007928:Lethal Dose 50; D009835:Oligochaeta / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D012098:Reproduction / Q000187:drug effects; D012989:Soil Pollutants / Q000633:toxicity*; D018675:Toxicity Tests / Q000379:methods
D007306:Insecticides; D012989:Soil Pollutants; D004390:Chlorpyrifos