汞及甲基汞在栉孔扇贝全组织内的积累与净化

Accumulation and depuration of mercury and MeHg in the tissue of Chlamys farreri

以栉孔扇贝Chlamys farreri为研究对象,暴露于不同浓度HgCl2溶液35d后,转入自然海水中净化30d,检测不同时间点栉孔扇贝全组织中总汞与甲基汞含量,研究二者在栉孔扇贝组织中积累与净化情况。实验采用Kahle的双箱模型,数据处理采用两组不同动力学参数的双曲线毒性动力学模型。拟合发现,总汞和甲基汞在栉孔扇贝组织内的积累与净化规律符合双箱动力学模型;浓度低于2μg/L的汞溶液对栉孔扇贝的慢性毒性较小;各实验组暴露35d后栉孔扇贝组织中的总汞含量达到最高,暴露浓度与扇贝组织内的总汞积累量呈正比例关系。总汞在栉孔扇贝组织内的富集高峰出现在第35天,与理论点一致,而甲基汞富集高峰出现在40d后,有延迟现象;对比总汞和甲基汞在栉孔扇贝组织内的积累与净化动力学参数发现,总汞在栉孔扇贝组织内的积累因子(BCF)总体上大于甲基汞在栉孔扇贝组织内的BCF;汞与甲基汞在扇贝组织内的BCF和生物学半衰期(B1/2)与暴露液浓度均呈正相关关系;海水环境中总汞浓度低于0.064 8μg/L时,对栉孔扇贝的食品安全性无影响(以甲基汞为限量)。

Chlamys farreri was cultured in HgCl2 solution at different concentrations for 35 days,then transferred to natural sea water and was purified for 30 days.Sampling was done at different time to detect total mercury and MeHg content in the tissue.Accumulation and purification of mercury and MeHg in the tissue was studied.The mercury solution was not toxic to the scallops when the concentration was lower than 2μg/L.Exposure concentration and accumulation of Hg in scallops showed a direct relationship.Kahle double-box model was used in the experiment design,and data was processed by hyperbolic toxicity kinetic model.The results showed that the accumulation and depuration of mercury and MeHg in the tissue of C.farreri was in line with the law of two-compartment kinetic model; total mercury accumulation in C.farreri showed the highest value at 35d,while the MeHg accumulation in C.farreri was delayed,and the highest peak was found at 40d.Comparing the biphasic kinetics parameters of mercury and MeHg accumulation and depuration in the tissue of C.farreri,it was found that the BCF of total mercury in the tissue of C.farreri was generally greater than the BCF of MeHg.The BCF and biological half-life of Hg ang MeHg in C.farreri correlated with exposure concentration.