基于本土物种的3种典型化合物急性生态效应阈值研究

预测无效应浓度(PNEC)是进行风险污染物水生态安全管理的重要依据。本研究进行了3种典型化合物五氯酚、硝基苯和氯化镉对10种我国不同营养级水生生物的24 h、48 h和96 h的急性毒性测试,根据实验结果计算了相应的急性PNEC,同时与根据美国环境保护局毒性数据库里的毒性数据计算获得的急性PNEC值,以及综合本实验结果与毒性数据库里的数据计算得到的急性PNEC值进行对比,发现通过3种数据来源获得的急性PNEC值中,硝基苯的PNEC值差异较大,由本次实验结果获得的急性PNEC值最小;其他2种化合物差异较小。这可能是由于本次实验所选的本土生物中华田螺和麦穗鱼对硝基苯比较敏感,并且数据库中硝基苯的急性致死数据较少、毒性值较大且变化范围较窄,而其他2种化合物数据量较为丰富,变化范围较宽,包括了较敏感物种的毒性数据。这表明为给我国水生生物提供一个安全可靠的保护,对于数据量较为丰富并且毒性值变化较宽的化合物(如五氯酚和氯化镉)可以直接根据数据库里的毒性数据进行PNEC值的计算;而对于毒性数据量较少、毒性值偏大且变化较窄的化合物(如硝基苯)需要进行本土敏感物种的毒性测试。

The Study of Acute Ecological Threshold (PNECs) of Three Typical Compounds Based on the Acute Toxicity of Native Aquatic Species

Prediction of no effect concentration (PNEC) is an important basis for the ecological risk management of pollutants. The acute toxicities of three typical pollutants (pentachlorophenol, nitrobenzene, cadmium chloride) to 10 aquatic organisms were tested, and their acute PNECs were calculated based on the toxicity data obtained from the toxicity test results in this study. At the same time, the acute PNEC values were also calculated based on the toxicity data collected from ECOTOX database and combined toxicity data from ECOTOX database and the toxicity test results in this study. The comparison of acute PNECs obtained by three toxicity data sources was performed and it is found that acute PNECs of nitrobenzene based on the toxicity data tested in this study are the lowest. While acute PNECs of pentachlorophenol and cadmium chloride based on three toxicity data sources are very similar. The possible reasons are that the aquatic organisms such as Cipangopaludina chinensis and Pseudorasbora parva are very sensitive to nitrobenzene in this study, and the acute lethal data size of nitrobenzene in ECOTOX database are very small and the values of acute toxicity data are higher than those of the sensitive species in this study. With respect to nitrobenzene, the toxicity data of pentachlorophenol and cadmium chloride are very abundant in ECOTOX database and include different sensitive species. It is indicated that for compounds such as pentachlorophenol and cadmium chloride with large toxicity data size and including toxicity data of sensitive species, a reliable PNECs could be calculated directly based on the toxicity data in ECOTOX database, while for the compounds such as nitrobenzene with small toxicity data size in ECOTOX database, toxicity test should be carried out to local sensitive species to calculate a reliable PNECs.