Institute of Hydrobiology, Jinan University, 510632, Guangzhou, PR China.
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, 430072, Wuhan, PR China.
Ecotoxicology. 2020 Aug;29(6):790-800. doi: 10.1007/s10646-020-02231-2. Epub 2020 May 19.
Bioaccumulation of microcystins (MCs) has been widely observed in aquatic vertebrates and invertebrates, but its seasonal and specific variations remain unclear. In the present study, dissolved MCs in water, algal cell-bound MCs and muscle tissue MCs of nine fish species were investigated monthly in two of the largest shallow lakes in China: Lake Taihu and Lake Chaohu. The fish species were grouped as carnivorous, planktivorous, and omnivorous fish. Seasonal variations in dissolved and algal cell-bound MCs in water and MCs contents of fish hepatopancreas and muscle were investigated in the two lakes from 2009 to 2010. Dissolved MCs in water ranged from 0.35 to 2.56 µg l in Lake Taihu and 0.16 to 2.45 µg l in Lake Chaohu, and showed seasonally a unimodal distribution. Algal cell-bound MCs also showed a similar seasonal variation in both lakes, but dissolved MCs in water peaked about one month later than algal cell-bound MCs. The MCs content in the Fish muscle was higher MCs from October to December than in the other months. For most of the fish species, it exceeded the tolerable daily intake value established by the WHO. The averaged MCs content in the muscle of carnivorous, planktivorous, omnivorous fish was 48.2, 28.7 and 37.8 μg kg in Lake Taihu, respectively, and 27.8, 18.6 and 20.4 μg kg in Lake Chaohu. It was significantly higher in carnivorous fish than in planktivorous and omnivorous fish, indicating that carnivorous fish has a higher exposure risk to the local people when consuming the harvested fish. The average ratio of hepatopancreas to muscle MCs contents was 13.0, 25.2, 13.8 for carnivorous, planktivorous, omnivorous fishes in Lake Taihu, respectively, and 18.0, 24.9, 14.8 in Lake Chaohu. These ratio for planktivorous fish almost doubled that for carnivorous and omnivorous fish. High correlation of MC content in carnivorous, omnivorous and planktivorous fish indicates that MCs can be delivered along trophic levels in the food chains.
微囊藻毒素（MCs）在水生脊椎动物和无脊椎动物中已被广泛观察到，但它的季节性和特定变化仍不清楚。本研究于 2009 年至 2010 年期间，每月调查了中国两个最大的浅水湖泊（太湖和巢湖）的 9 种鱼类的水中溶解态 MCs、藻类细胞结合态 MCs 和肌肉组织 MCs，并将鱼类分为肉食性、浮游生物食性和杂食性鱼类。调查了这两个湖泊中鱼类肝胰腺和肌肉中溶解态和藻类细胞结合态 MCs 以及 MCs 含量的季节性变化。太湖水中的溶解态 MCs 范围为 0.35 至 2.56μg/l，巢湖为 0.16 至 2.45μg/l，呈单峰分布。两个湖泊中的藻类细胞结合态 MCs 也呈现出相似的季节性变化，但水中的溶解态 MCs 比藻类细胞结合态 MCs 晚一个月达到峰值。鱼类肌肉中的 MCs 含量从 10 月到 12 月高于其他月份。对于大多数鱼类物种，其含量超过了世界卫生组织（WHO）制定的可耐受日摄入量值。太湖肉食性、浮游生物食性、杂食性鱼类肌肉中的 MCs 含量平均值分别为 48.2、28.7 和 37.8μg/kg，巢湖分别为 27.8、18.6 和 20.4μg/kg。肉食性鱼类的 MCs 含量明显高于浮游生物食性和杂食性鱼类，这表明当当地居民食用收获的鱼类时，肉食性鱼类面临更高的暴露风险。太湖肉食性、浮游生物食性、杂食性鱼类肝胰腺与肌肉 MCs 含量的平均比值分别为 13.0、25.2、13.8，巢湖分别为 18.0、24.9、14.8。浮游生物食性鱼类的比值几乎是肉食性和杂食性鱼类的两倍。肉食性、杂食性和浮游生物食性鱼类的 MC 含量呈高度相关，表明 MCs 可以沿食物链在营养级间传递。
