摘要:
为评估湘江水体中铜的生物有效性,通过铜对青鳉的急性毒性实验确定铜对青鳉的半致死浓度(LC50),然后利用生物配体模型(Biotic Ligand Model,BLM)确定青鳉的累积半致死浓度(LA50)。同时对湘江水样的预测结果表明,铜对青鳉的LA50为12.43 nmol·gw-1;BLM预测的与实验观测的LC50差异倍数小于2,表明BLM预测结果比较准确。在此基础上预测铜对青鳉LC50预测范围为344.70~761.96 μg·L-1。湘江各点水质最终急性值(FAV)相差不大(11.04~14.25 μg·L-1),但水中溶解态铜含量相差较大(0.29~10.48 μg·L-1),同时毒性单位值(TU)相差较大(0.06~1.48 μg·L-1),其中最小值在舂陵水入湘江下游采样断面,最大值在株洲断面。在全部调查断面中,只有株洲断面TU大于1(1.48),说明株洲断面水中铜含量超过了该断面水中BLM确定的水质基准的1.48倍。
Abstract:
To evaluate copper bioavailability in Xiangjiang River, acute toxicity tests of copper to medaka were performed and the lethal concentration 50 (LC50) was obtained. Then, the lethal accumulation 50 (LA50) of copper to medaka was calculated by Biotic Ligand Model (BLM). The predicted values by BLM showed that LA50 of copper to medaka was 12.43 nmol·gw-1. The ratio of LC50obtained from the predicted value and actual test value was no more than 2, indicating that the LC50 evaluated by BLM was reasonable. Thus, LC50 of medaka to copper predicted by BLM ranged from 344.70 to 761.96 μg·L-1. In addition, final acute value (FAV) of samples from Xiangjiang River ranged from 11.04 to 14.25 μg·L-1, while the contents of dissolved Cu ranged from 0.29 to 10.48 μg·L-1. Moreover, the ratios of actual concentrations and criterion maximum concentration ranged from 0.06 to 1.48 μg·L-1and only the ratio in Zhuzhou site was more than 1 (1.48), implying that the contents of dissolved Cu was 1.48-fold of the water quality criteria predicted by BLM.
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