根据SSD推导PFOS沉积物质量基准及其在生态风险评估中的应用

沉积物中蓄积的PFOS（perfluorooctane sulfonate，全氟辛烷磺酸）对水体生态环境具有潜在的危害.为了合理评估沉积物中PFOS的危害，探究了沉积物中PFOS对摇蚊（Chironomus kiiensis）、钩虾（Hyalella azteca）、霍甫水丝蚓（Limnodrilus hoffmeisteri）等底栖生物的毒性效应；同时，以毒性试验结果和搜集的PFOS相关毒性数据为基础，利用SSD（species sensitivity distributions，物种敏感度分布法）推导PFOS沉积物质量基准；最后，将基准值与从文献中搜集得到的我国七大水系沉积物中w（PFOS）进行比较，以评估PFOS风险.结果表明:①沉积物中PFOS对摇蚊的毒性效应最为显著，其96 h、10 d、21 d毒性试验中LC₅₀分别为0.894、0.770和0.536 μg/g（以干质量计，下同）；10 d毒性试验中w（PFOS）最高值为156.5 μg/g时，钩虾未出现显著死亡，21 d毒性试验中LC₅₀为70.5 μg/g；在w（PFOS）最高值分别为112.4和76.4 μg/g的10和21 d毒性试验中，霍甫水丝蚓均未出现显著死亡.②沉积物中PFOS的CMC_sed（急性基准值）为28.6 μg/g，CCC_sed（慢性基准值）为0.060 μg/g.③我国七大水系96.0%的沉积物中w（PFOS）低于CCC_sed；其余的沉积物中w（PFOS）高于CCC_sed但低于CMC_sed，这些采样点主要分布在黄河中下游和长江下游.研究显示，我国七大水系沉积物中PFOS总体风险较低，但黄河中下游和长江下游沉积物中蓄积的PFOS可能具有潜在的风险，需要给予更多的关注. 

Derivation of Sediment Quality Criteria of PFOS based on SSD and Its Application in Ecological Risk Assessment

The accumulation of PFOS (perfluorooctane sulfonate) in sediments has a potential hazard to the aquatic ecosystem. In order to evaluate the adverse effects of PFOS in sediments, the toxic effects of PFOS in sediments on benthic organisms, including Chironomus kiiensis, Hyalella azteca and Limnodrilus hoffmeisteri, were investigated using mortality and growth-inhibition as toxic endpoints. Based on the results of toxicity experiments and collected toxicity data from the references, the sediment quality criteria (SQC) of PFOS was derived by species sensitivity distributions (SSD). Based on the obtained SQCs of PFOS, the ecological risk of PFOS in the sediments of seven major river systems in China was evaluated. The results showed that:(1) The toxic effect of PFOS on Chironomus kiiensis was the most significant, and the LC₅₀ values were 0.894, 0.770 and 0.536 μg/g for the 96 h, 10 d and 21 d toxicity tests, respectively. No death was observed in the 10 d toxicity test (maximum concentration 156.5 μg/g) of the Hyalella azteca, while the LC₅₀ was 70.5 μg/g in the 21 d toxicity test. As Limnodrilus hoffmeisteri was used, no significant death occurred in the 10 d toxicity test (maximum concentration 112.4 μg/g) and 21 d toxicity test (maximum concentration 76.4 μg/g). (2) The CMC_sed was 28.6 μg/g and the CCC_sed was 0.060 μg/g. (3) The w(PFOS) was lower than CCC_sed in the sediments of 96% of China's seven major river systems, while the w(PFOS) was higher than CCC_sed but lower than CMC_sed in other sediments, which was mainly distributed in the middle and lower reaches of the Yellow River and the lower reaches of the Yangtze River. In conclusion, the overall risk of PFOS in the sediments of the seven major river systems in China is relatively low, but the PFOS in the sediments of the middle and lower reaches of the Yellow River and the lower reaches of the Yangtze River may have potential risks and need more attention.