Behavior of microcystins and its decomposition product in water treatment process

Microcystins are well known as a liver tumor promotors. Recently, we identified (2S, 3S, 8S)-3-amino-2,6,8-trimethyl-10-phenyldeca-4E, 6E-dienoic acid (DmADDA) as the decomposition product of microcystins by iron(III) chloride in vitro. Therefore, we measured the level of microcystins and DmADDA in the water purification facility for a year. DmADDA was not only detected in the surface water without toxic blue-green algae, but was also detected in the landing water and purified water. The levels of DmADDA were from ND to 1.82 μg/ml in the surface water, those in the landing water were from ND to 0.64 μg/ml, and those in the purified water were from ND to 0.42 μg/ml. The levels of microcystins (the value converted to microcystin LR) were from ND to 0.16 μg/ml in the surface water. Those in the landing water were from ND to 0.29 μg/ml and microcystins were not detected in the purified water during the year.