摘要:
为对比微宇宙方法和物种敏感度分布曲线法在铜离子生态危害评估中的差异,构建了包括浮游藻类、轮虫和大型溞的微宇宙系统,持续监测了铜离子浓度、物种丰度和系统理化性质的变化,推导出铜离子对微宇宙系统的63 d无显著效应浓度(63 d-NOEC);同时,将铜离子对鱼类、甲壳类、昆虫类、藻类及软体动物等对铜离子的长期毒性数据通过物种敏感度分布曲线法进行拟合,推导出对生态系统中95%物种无显著危害的作用浓度(HC5)。测试结果表明,大型溞种群在铜离子110.80μg·L-1作用下暂时消失,导致了系统中轮虫和藻类数量的增长,试验后期铜离子浓度降低,大型溞种群呈现恢复的趋势;在212.06及420.26μg·L-1铜离子作用下,藻类和轮虫的存活受到严重抑制,在试验后期也没有恢复。与物种敏感度分布曲线法推导得出的HC5值相比,通过微宇宙系统得出的NOEC值较高,这可能是微宇宙系统中铜离子生物可利用性在各相介质间的差异及种间反馈调节造成的。
Abstract:
To compare the differences between microcosm study and species sensitivity distribution approach in ecological hazard assessment of copper ion,a microcosm system contained planktonic algae,rotifers and daphnia was built and the dynamics of copper ion concentration,species abundances and physicochemical properties of the system were monitored for 63 d. And on this basis the 63 d-NOEC(no observed effect concentration) of copper ion forthe microcosm system was calculated. In the meantime,species sensitivity distribution curves were constructed with chronic toxicity data for fish,crustacean,insects,algae and mollusk,which gave a no obvious hazard concentration for 95% species in the ecosystem(HC5). According to test results,Daphnia magna had disappeared for a short time at 110.80 μg·L-1 treatment,which led to the increase of rotifers and algae abundances. However,in the later period of the test the recovery of Daphnia magna was observed at 110.80 μg·L-1 treatment due to the decrease of the measured copper ion concentration. While for 212.06 and 420.26 μg·L-1 treatments,the survival of rotifers and algae were strongly inhibited and no recovery had been observed till the end of test. Compared to HC5 value calculated by the species sensitivity distribution approach,the 63 d-NOEC derived from microcosm study was much higher than HC5. Possible causes might be the different bio-availability of copper ion in different phases of medium and the interspecies feedback included in the microcosm.
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