ABSTRACT
<p><b>OBJECTIVE</b>To identify and determine the congener and level of microcystins in the source water of Taihu Lake.</p><p><b>METHODS</b>Improved method of SPE combined with HPLC was employed to detect the concentration and varieties of microcystins in source water and bloom samples collected from Meiliang Bay, Taihu Lake.</p><p><b>RESULTS</b>The contents of two predominant microcystin components, MC-RR, and MC-LR, were relatively high in samples during warm months and correlated with the phase of algae growth. The maximum concentrations of MC-RR and MC-LR in water sample reached 3.09 +/- 0.53 microg/L and 2.39 +/- 0.41 microg/L during the period of water bloom in September 2004, respectively. Even without waterbloom, the concentration of MC-LR in source water sample was still higher than the guideline value.</p><p><b>CONCLUSION</b>The status of microcystin pollution in this region is serious and measures to monitor and control the growth of cyanobacteria are urgently needed.</p>