实测/预测辽河铬(Ⅵ)水生生物基准与风险评估

Measured and Predicted Aquatic Life Criteria and Risk Assessment of Chromium( Ⅵ) in Liaohe River

该研究对辽河流域重金属铬(Ⅵ)的水生生物毒性数据进行搜集与筛选,推导辽河流域铬(Ⅵ)的水生生物基准值,并对辽河流域25个采样点位采集水样,测定铬(Ⅵ)的环境暴露浓度,最后对辽河流域水生生物铬(Ⅵ)暴露的潜在风险进行评估.此外,采用美国环境保护署(US EPA)物种种间关系估算模型(ICE)对辽河流域物种毒性值进行预测,并对基于预测毒性值的水生生物基准进行推导.结果表明,辽河流域基于实测毒性数据的水生生物急性基准值(CMC)为17.73μg·L-1,慢性基准值(CCC)为12.15μg·L-1;ICE模型预测的辽河流域生物毒性值推导的CMC值为13.97μg·L-1,实测CMC值与预测值比较接近,表明ICE模型可应用于水生生物基准值的预测.铬(Ⅵ)的水质分析结果表明25个采样点位水体铬(Ⅵ)浓度较低,均达到GB 3838-2002地表水质标准中铬(Ⅵ)的Ⅰ类或Ⅱ类标准,水质状况良好;然而,在对水生生物的潜在风险方面,通过生态风险评估得出7月辽河流域25个点位中环境暴露值超过慢性基准CCC值的有7个,12月超过慢性基准CCC值的有6个,表明辽河流域个别点位铬(Ⅵ)暴露可能会对水生生物产生不可接受的风险.

In this study,toxicity data of aquatic species in Liaohe River for heavy metal chromium( Ⅵ) was collected and selected.The aquatic life criteria for chromium( Ⅵ) in Liaohe River was derived based on these toxicity data.Moreover,water samples of 25 sites in Liaohe River were collected,and the concentrations of chromium( Ⅵ) in these samples were analyzed.Finally,ecological risk assessment of chromium( Ⅵ) in Liaohe River was performed.Moreover,interspecies correlation estimation method( ICE) established by US EPA was used to predict the acute toxicity of species in Liaohe River,and aquatic life criteria based on predicted toxicity data was derived.The results showed that: the measured CMC( criteria maximum concentration),measured CCC( criteria continuous concentration) and the predicted CMC were 17.73,12.15 and 13.97 μg·L- 1,respectively.Therefore,the ICE method could be used to predict the aquatic life criteria,because the predicted criteria value was very similar to the measured criteria value.Analysis of chromium( Ⅵ) showed that the chromium( Ⅵ) concentrations of the 25 sites in Liaohe River were all below Class I or Class Ⅱ water quality standards( GB 3838-2002),and the water quality was in good condition.However,for the potential risk of chromium( Ⅵ)exposure to the aquatic life of Liaohe River,the result of ecological risk assessment showed that chromium( Ⅵ) concentrations in 7sites exceeded the CCC in July, and chromium( Ⅵ) concentrations in 6 sites exceeded the CCC in December.Therefore,unacceptable effect on aquatic species caused by chromium( Ⅵ) exposure might have occurred in some sites of Liaohe River.