Anabaena sp. bloom and the occurrence of microcystin- LR from a eutrophic pond in Bangladesh

Abstract

A bloom of Anabaena sp. occurred in a freshwater pond in Brahmanbaria. Bloom sample was collected and filtered through a glass fiber filter. Methanol-water extract of filtered cells were analyzed by high performance liquid chromatography (HPLC) with UV, MS and MS-MS detection detected three variants of microcystins viz, [D-Asp 3 , Dha 7 ] Microcystin-LR, [Dha 7 ] Microcystin-LR and Microcystin-LR. The total concentration of microcystins was 4.0 μg l -1 , well above the WHO provisional guideline value for drinking water. So, the cyanotoxin risk assessment has become important to protect public health in Bangladesh where surface water is used as drinking-water source.