砷在海洋食物链中的生物放大潜力及发生机制探讨

Biomagnification Potential and the Mechanisms of Arsenic in Marine Food Chains

砷是世界范围内危害最大的环境污染物之一,也是近海区域一种常见污染物。本文综述了近年来砷在海洋生态系统中累积、转化及传递的最新研究进展。海洋生物普遍具有较高含量的砷,这些砷主要为低毒性的有机砷形态。砷在许多海洋食物链/网中被生物放大,造成高营养级生物中的砷富集,可对生物与人类健康产生潜在危害;这与砷在淡水食物链/网中普遍被生物减小的现象形成鲜明对比。海洋鱼类和贝类等生物可将吸收的无机砷通过生物转化合成砷甜菜碱等有机砷形态,而有机砷比无机砷具有更高的食物链传递能力,可导致海洋鱼类富集更高浓度的砷。因此,砷在海洋生物中的有机形态可能有助于砷沿着海洋食物链/网富集,在某些情况下被生物放大。今后应该加强对不同砷形态在海洋食物链/网中传递及相应影响因素的研究,并通过室内模拟实验与野外调查相结合进行验证,从而加深对砷的生态毒理和生物地球化学作用的科学认识,对准确评估预测砷的生态风险和保障海洋生态安全有重要意义。

Arsenic (As) is one of the most hazardous environmental pollutants and widely exists in the coastal area.This paper reviews the bioaccumulation,biotransformation and trophic transfer of As in marine ecosystems.Marine organisms usually accumulate high level of As mainly in low-toxic organic species.As could be biomagnified along some marine food chains/webs,resulting in the high bioaccumulation in higher trophic levels and potential harm to these organisms.In contrast,As is commonly biodiminished in freshwater food chains/webs.Marine fish and shellfish could biotransform inorganic As to organic species,especially to arsenobetaine,which have higher trophic transfer ability and then cause high As bioaccumulation.As biomagnification is probably related to the high content of organic As species in marine organisms.The future research should pay more attention to the biomagnification potential of specific As species by the combination of field investigation and indoor experiments.It will be helpful for the better understanding of the ecotoxicology and biogeochemistry of As,the assessment of the ecological risks of As,and the safeguard of the marine ecological safety.