Use of protein phosphatase inhibition assay to detect microcystins in Donghu Lake and a fish pond in China

Seasonal variations in the level of total microcystins in water samples col lected from Donghu Lake and a fish pond in Wuhan, China, were studied betwe en March 1995 and February 1996 using a protein phosphatase inhibition assa y involving a radioactive P-32-labelled substrate. The assay is highly reli able and repeatable, and is probably the most sensitive assay for microcyst in detection to date. Results of the survey indicated the presence of micro cystins in the water samples, and the concentration of microcystins appeare d to be related to the degree of eutrophication and water temperature. Ther e is also a correlative relationship between the quantity of microcystins a nd the abundance of microcystin-producing cyanobacteria (Anabaena and Oscil latoria) in the water bodies over a year cycle. In the present study, the p ositive detection of microcystins in water bodies having no signs of algal bloom warns of considerable potential threat of these waters to public heal th. (C) 2000 Elsevier Science Ltd. All rights reserved.