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Environmentally relevant concentrations of organotin compounds (OTs) may trigger sex changes in marine invertebrates and pose a threat to the marine ecosystem. In this study, we investigated organotin levels and the biological responses of wild veined rapa whelk (Rapana venosa) from Lüjuhe district (LJH), Dashentang district (DST), and Nanpaihe district (NPH) in Bohai Bay, China. We found that 11.11 and 22.95 % of the veined rapa whelks from DST and NPH exhibited imposex characteristics with a relative penis size index (RPSI) of 12.50 and 12.31, respectively. The RNA/DNA ratio was significantly lower in females from DST than those from LJH (p < 0.05), and a slight increase in DNA damage was observed in females and imposex individuals compared to males. Moreover, less genetic distance occurred between LJH and NPH (0.016) than between LJH and DST (0.028), although they belonged to the same regional population. OTs analysis showed that triphenyltin chloride concentrations (41.45 ng/g dried weight) were significantly higher than tributyltin concentrations (9.51 ng/g dried weight) in tissues (p < 0.05), but no significant differences were observed in sediments (p > 0.05). In conclusion, the occurrence of imposex individuals and biological responses of the wild veined rapa whelk from Bohai Bay suggest that the marine ecosystem might be at risk.

The present study evaluated the potential ecological risk of organotin compounds (OTs) to wild veined rapa whelk (Rapana Venosa) population in Bohai Bay. The results showed that the imposex rate was 12.5% and 6.48% in Dashentang and Nanpaihe coastal areas, with relative penis size index of 9.61 and 12.45, respectively. The concentrations of butyltin compounds and phenyltin compounds were 39.04 ng x g(-1) dw and 46.48 ng x g(-1) dw in muscle tissues, and 32.09 ng x g(-1) dw and 109.03 ng x g(-1) dw in digest gland, respectively. Based on TBT levels in the muscles of all samples, a risk quotient of 0.024 was derived, indicating certain risk of OTs at current levels to wild veined rapa whelk populations in Bohai Bay.

In order to explore the potential ecological risk of heavy metals in Three Gorges Reservoir areas, the present study analyzed the heavy metals in sediments and wild crucain carp from Daning River and Modaoxi River which are two typical tributaries, and then the potential risk was evaluated using potential ecological risk index for sediments and comprehensive pollution index for fish, respectively. The results showed that concentrations of Zn and Cr were higher (Daning River: 78.31 and 83.98 mg x kg(-1); Modaoxi River: 99.03 and 94.20 mg x kg(-1)), while Cd was the lowest (Daning River: 0.62 mg x kg(-1); Modaoxi River: 0.75 mg x kg(-1)). Moreover, an obvious increasing trend of these elements was observed in these tributaries from upstream to downstream. For the wild crucain carp, the lowest concentrations of these elements were detected in muscles, and the highest concentrations were in the intestinal. However, no obvious increasing trend of these elements was observed from upstream to downstream. The potential ecological risk in sediments showed a high risk, while no risk was observed in fish.