水体BTEX污染对大型溞和霍普水丝蚓的毒性效应及水环境安全评价

以大型溞(daphnia magna)和霍普水丝蚓(Limnodrilus hoffmeisteri)为受试生物,研究了甲苯、乙苯和二甲苯等苯系物(BTEX)的水生生态毒性效应.结果表明,3种污染物对大型溞和霍普水丝蚓毒性影响呈明显的剂量-效应关系,且毒性作用随暴露时间延长而增加.水体中甲苯、乙苯和二甲苯污染对大型溞的24h EC50分别是172.1、50.1和63.6 mg·L-1,48h EC50分别是136.9、42.9和50.3 mg·L-1;对霍普水丝蚓的24hLC50分别是194.8、71.9和88.0 mg·L-1;48h LC50分别是185.2、46.8和75.6 mg·L-1;96h LC50分别是170.4、38.8和71.9 mg·L-1.根据3种污染物对2种受试生物的毒性试验结果,预测水体中甲苯、乙苯和二甲苯的安全浓度sc分别为13.7、3.9和5.0 mg·L-1,最大允许浓度MPC分别为1.4、0.4和0.5 mg·L-1.

Toxic effects of BTEX in water on Daphnia magna and Limnodrilus hoffmeisteri and safety assessment of the aquatic environment

Aquatic ecotoxicological effects of toluene, ethylbenzene and xylene were investigated using Daphnia magna and Limnodrilus hoffmeisteri as test living organisms. The results indicated that there were significantly positive correlations between the inhibitory or lethal effects on Daphnia magna and Limnodrilus hoffmeister and the concentrations of the three chemicals in aquatic environment. The toxic action was increased with prolongation of the exposure time. The 24 h EC50 values of toluene, ethylbenzene and xylene to Daphnia magna were 172.1, 50.1 and 63.6 mg·L-1, and the 48 h EC50 values were 136.9, 42.9 and 50.3 mg·L-1, respectively. The 24 h LC50 values of toluene, ethylbenzene and xylene to Limnodrilus hoffmeisteri were 194.8, 71.9 and 88.0 mg·L-1, the 48 h LC50 values were 185.2, 46.8 and 75.6 mg·L-1, and the 96 h LC50 values were 170.4, 38.8 and 71.9 mg·L-1, respectively. According to the results of the acute toxicity tests on Daphnia magna and Limnodrilus hoffmeister, the predicted safe concentrations (SC) of toluene, ethylbenzene and xylene in the aquatic environment were 13.7, 3.9 and 5.0 mg·L-1, and their maximum permissible concentrations (MPC) were 1.4, 0.4 and 0.5 mg·L-1, respectively.