Abstract:

Margarya melanioides〖WTBZ〗 Nevill,an important economic mollusk,is an endemic gastropod in China,and mainly distributes in plateau lakes of Yunnan Province.In order to investigate the bioaccumulation of microcystins(MCs)in various tissues of 〖WTBX〗Margarya melanioides,〖WTBZ〗the snail samples were collected monthly in January and from May to Octomber,2008.Microcystins contents in hepatopancreas,digestive tracts,gonads and muscle were measured with ELISA.During the study period,the average of the MCs contents in hepatopancreas,digestive tracts,gonad and muscle of 〖WTBX〗Margarya melanioides〖WTBZ〗 were 338±190,272±163,123±097 and 035±043 μg/g DW,respectively.MCs contents in hepatopancreas had no significant difference with MCs contents in digestive tracts.MCs contents in these two tissues were significant higher than those in gonad,and that in gonad tracts were significant higher than those in muscle.The highest microcystins levels of various tissues occurred in July,and the lowest contents occurred in May.MCs contents in hepatopancreas and in gonad had significant positive correlation with the total MCs concentrations in surrounding water columns.According WHO proposed a provisional tolerable daily intake(TDI) of 004 μg/kg bw per day for MCLR to estimate,considering an adult of 60 kg,who ingests,on the average,03 kg of snail muscle or 03 kg of snail gonad a day,the contents in edible parts of 〖WTBX〗Margarya melanioides 〖WTBZ〗were above the provisional WHO TDI level, suggesting the risk of consuming 〖WTBX〗Margarya melanioides〖WTBZ〗 in Lake Dianchi.