淡水沉积物中Cd和Cu对河蚬的毒性效应研究

以淡水底栖动物河蚬(Corbicula fluminea)为受试生物,研究了淡水沉积物中重金属Cd和Cu对河蚬的12h挖洞行为和10d存活率的影响.结果表明,河蚬对加标Cd和Cu的淡水沉积物均产生了明显的规避行为.在12h挖洞行为试验中,河蚬对沉积物中Cd的污染反应比Cu更加灵敏,暴露于Cd和Cu的10mg/kg的沉积物中时,河蚬的挖洞比率分别为0.39和0.43.在10d存活率试验中,河蚬的存活率随沉积物中Cd和Cu浓度的升高而降低.在Cd加标浓度为10mg/kg的沉积物中,河蚬的存活率为93.3%,当Cd加标浓度达到300mg/kg时,河蚬存活率降为43.3%;在Cu加标浓度为10mg/kg的沉积物中,河蚬存活率为96.3%;而当Cu加标浓度达到500mg/kg时,河蚬存活率降为34.3%.加标Cd和Cu的两种淡水沉积物对河蚬的LC₅₀分别为285、690mg/kg,表明河蚬对Cd的毒性反应更加灵敏.比较河蚬的挖洞行为和存活率对重金属Cd和Cu的指示作用,挖洞行为比存活率更加快捷,对沉积物中Cd和Cu的指示作用更加明显,故在沉积物重金属污染监测中应优先考虑挖洞行为.

The toxic effects of Cd and Cu in freshwater sediments on Corbicula fluminea

To study the effects of heavy metal Cd and Cu in freshwater sediment on the freshwater benthic organism, the burrowing behavior of Corbicula fluminea within 12 hours and survival rate during 10days were analyzed. The results showed that Corbicula fluminea exhibited a significant avoidance behavior to the spiked Cd and Cu in freshwater sediment. Within 12 hours, the response of Corbicula fluminea to Cd in sediment is more sensitive than Cu. Under exposure to Cd and Cu at 10mg/kg, the burrowing rate of Corbicula fluminea were 0.39 and 0.43, respectively. In the survival test during 10 days, the survival rate of Corbicula fluminea decreased corresponding to the increase of Cd and Cu concentrations. At 10mg/kg of spiked Cd in sediments, the survival rate of Corbicula fluminea was 93.3%. However, the survival rate dropped to 43.3% at 300mg/kg. For spiked Cu in sediment, the survival rate of Corbicula fluminea was 96.3% at 10mg/kg and decreased to 34.3% at 500mg/kg. The LC₅₀ of Corbicula fluminea were 285mg/kg for spiked Cd and 690mg/kg for spiked Cu, respectively. All these data revealed that Corbicula fluminea was more sensitive to the toxicity of Cd. By comparing the indicative features of burrowing behavior and survival rate of Corbicula fluminea when exposed to heavy metal Cd and Cu, burrowing behavior was found to be more quickly and more obviously than survival rate., indicating that a high priority should be given to burrowing behavior in heavy metal contamination monitoring.