The Endocrine Disrupting Effects Of Three Bisphenol Analogues On Chironomus Tentans

On the basis of standard breeding environment conditions for chironomus tentans, the acute toxicity, the whole life circle toxicity and the endocrine disruption toxicity of bisphenol B (BPB), bisphenol AP (BPAP) and bisphenol P (BPP) to chironomus tentans are defined in this paper. The influence of different exposure modes on the whole life circle toxicity of chironomus tentans is also studied. It is preliminarily explored how BPP affects the antioxidant enzyme activity of chironomus tentans for several generations. The research results and main conclusions are shown as below:1) Different temperatures and light intensities lead to different developmental rates, death rates and sex ratios for chironomus tentans. Four different temperatures and two different light intensities were designed in this paper. It was found that under the condition of that the temperature was 25℃ and the light intensity was 8001ux, the sex ratio (male/female) of adult chironomus tentans was 1.07 and the death ratereached the minimum. Besides, under the condition mentioned above, the population index hits 113.95, the highest of all the experiments. So, the results showed that the suitable conditions for chironomus tentans to grow, develop and breed in the laboratory are as follows:temperature:25℃; light intensity:8001ux.2) The acute toxicities of the three kinds of phenolic chemical which were BPB, BPAP and BPP were high to larvas of chironomus tentans. The data of the acute toxicity provided the foundation for study on the whole life circle toxicity. The EC50 of BPB and BPAP for first instar chironomus tentans in 48 hours were 4.762 mg/L and 0.727 mg/L respectively. The EC50 of BPP for first instar chironomus tentans in 24 hours was 0.585mg/L. So, the toxicities of the three kinds of phenolic chemical to larvas of chironomus tentans were arranged in order of toxicity:BPP>BPAP>BPB.3) The whole life circle toxicities of BPB and BPAP to chironomus tentans were studied through standard additions method of water. The BPB’s NOEC of developing rate for P generation was 50.13 μg/L. The BPB’s LOEC of developing rate for offspring F1 was 19.09μg/L. The BPB’s LOEC value of developing rate for offspring chironomus tentans was lower than the BPB’s NOEC value of developing rate.for parent chironomus tentans, which indicated that the offspring were more severely influenced by BPB than the parent. The same result was found in BPAP, too. At the same time, BPB caused severe influence on the sex ratio of P generation with the NOEC value being 208.33 μg/L. It was not observed that the emergency rates and the fertility of P generation and F1 generation were obviously influenced by the highest concentration group of BPB, which was as high as 535.93 μg/L. It was not observed that the emergency rates, the sex ratios and the fertility of P generation and F1 generation were obviously influenced by the highest concentration group of BPAP, which was as high as 111.21 μg/L. The experiment results showed that BPB and BPAP might affect the endocrine changes in chironomus tentans at same degree. The reason might be that the estrogenic activities of BPB and BPAP made some kind of hormone in chironomus tentans change to some extent to result in the change of developmental rate.4) The whole life circle toxicities of BPAP and BPP to chironomus tentans were studied through standard additions method of sediment. The result was that P generation were notobviously influenced by BPAP and BPP. The BPAP’s NOEC of developing rate for F1 generation was 0.43μg/g and for BPP it was 0.014μg/g. Besides, the emergency rates of P generation and F1 generation were influenced by BPAP and BPP to some degree. It was not observed that the developmental rate of P generation was obviously influenced by the highest concentration group of BAPB, which was 1.47μg/g. The sex ratios and the fertility of P generation and F1 generation were not affected obviously by the highest concentration group of BAPB. It was not observed that the developmental rate of parent chironomus tentans was obviously influenced by the highest concentration group of BPB, which was 0.151 μg/g. The sex ratios and the fertility of P generation and F1 generation were not affected obviously by the highest concentration group of BPB. In the experiment of whole life circle toxicity for the three kinds of phenolic chemical, it was found that the developmental rate of chironomus tentans was obviously influenced by these chemicals. The results also showed that developmental rate was a relatively sensitive index to judge the endocrine disturbing effect of phenolic chemicals on chironomus tentans.5) Standard additions methods of BPAP sediment and water were compared about how they affected the whole life circle toxicity experiment results on chironomus tentans. BPAP influenced the developmental rate of F1 generation in both methods. The NOEC of standard additions methods of sediment was lower than that of standard additions methods of water. The explanation for it was that BPAP might have strong soil absorption capacity while larvas of chironomus tentans lived in the sediment. As a result, it was better to do the whole life circle toxicity experiment on chironomus tentans in standard additions methods of sediment.6) The antioxidant systems of P generation and F1 generation were influenced by BPP to different degrees. As the concentration rose, the CAT activity expressions of P generation and F1 generation were restrained by BPP to do their jobs. Also, the SOD activity of chironomustentans F2 was reduced remarkably.