土壤辛硫磷污染对蚯蚓的生态毒理效应研究

Ecotoxicological effect of phoxim pollution in soil on earthworms

采用经济合作与发展组织(OECD)标准法配置的人工土壤研究了不同初始质量浓度(25、50、100 mg/kg)辛硫磷对蚯蚓的生态毒理效应,测定了不同老化时间(7、14、21、28 d)下蚯蚓体内及土壤中辛硫磷含量及各项生态毒理指标。结果表明:28 d内辛硫磷在蚯蚓体内及土壤中的含量持续降低;蚯蚓体内蛋白质随老化时间的延长逐渐降低;超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性随辛硫磷初始浓度增加总体呈先升后降的趋势,随老化时间的延长,SOD活性总体降低,而CAT活性先降后升;28 d时丙二醛(MDA)含量达到最高,且随辛硫磷初始浓度增加而总体显著提高(P<0.05);土壤酸性磷酸酶(ACP)活性随辛硫磷初始浓度增加而总体提高,而土壤脲酶(UE)活性随老化时间的延长总体增加。综合而言,SOD活性、CAT活性、MDA含量及土壤ACP活性可作为评价辛硫磷生态毒理效应的生物标志物,在有机磷农药的环境安全性评价过程中应给予考虑。

The subacute toxicity of the phoxim at different concentrations( 25,50,100 mg/kg) to earthworm was studied by OECD artificial soil method. The phoxim concentrations in the soil and earthworms and ecotoxicological indexes were measured at the 7^(th),14^(th),21^(st) and 28^(th) aging day,respectively. Results were as follows: the phoxim concentrations in earthworms and soil kept decreasing within 28 days. The protein concentrations in earthworms decreased with time prolonged. Superoxide dismutase( SOD),catalase( CAT) activity in earthworms increased first and then decreased with initial concentrations of phoxim increasing. With the aging time increasing,the former activity kept decreasing,while the later tended to decrease first and then rise again. Malondialdehyde( MDA) concentration in earthworms reached the maximum on the 28^(th) day,which increased significantly with initial phoxim concentration increasing in soil( P<0.05). The activity of alkaline phosphatase( ACP) in soil increased with initial phoxim concentration increasing,while that of urease( UE) rose with aging time. In conclusion,SOD activity,CAT activity,MDA concentration and soil ACP activity could be used as biomarkers for evaluation of ecotoxicological effect of phoxim,which should be considered in the environmental security assessment of organophosphorus pesticide.