Bioaccumulation Of The Hepatotoxic Microcystins In Aquatic Animals Of Lakes Chaohu And Taihu With Potential Risk To The Safety Of Aquatic Products

The frequency and intensity of cyanobacterial blooms increase with the progress of eutrophication in fresh waters worldwide. Among cyanotoxins, the hepatotoxic microcystins (MCs) are considered to be one of the most dangerous groups, since they are potent hepatotoxin, probable tumor promoters and inhibitor of protein phosphatases-1 and -2A. Due to universality and durative, as well as stability and water-solubility in freshwaters, microcystins are receiving increasing attention around the world as a public health concern. In this paper, studies were conducted to examine the tissue distributions and seasonal dynamics of MCs in various aquatic invertebrates and fish in Lakes Chaohu and Taihu. The main results and conclusions are as follows:Tissue distributions and seasonal dynamics of MC-LR and -RR in two freshwater shrimps, Palaemon modestus and Macrobrachium nipponensis were studied monthly (during June–November, 2003) in Lake Chaohu with toxic cyanobacterial blooms. MCs were quantitatively determined by High-Performance Liquid Chromatography (HPLC) with a qualitative analysis by a Finnigan LC–MS system. The shrimps P. modestus and M. nipponensis accumulated high MCs not only in the hepatopancreas (mean 4.29 and 0.53μg g^-1 DW, respectively) but also in the gonad (mean 1.17 and 0.48μg g^-1 DW, respectively), and the crayfish Procambarus clarkii accumulated as much as 0.93μg g^-1 DW in the gonad. These results indicates that gonads of the invertebrates are the second important target organ of MCs. P. modestus apparently accumulated more MCs in their organs than M. nipponensis, which might be a reflection of their difference in trophic niche. Eggs of the shrimps...