Objective To quantify microcystins (MCs:MC-LR, MC-RR, MC-YR) in urban drinking water of a city along the south of Yangtze River and to conduct a preliminary health risk assessment.
Methods From June 2010 to May 2011, the drinking water was monthly sampled in each district of the selected city. After the water samples were cleaned and enriched by solid phase extraction (SPE) using C18, the three typical MCs, MC-LR, MC-RR, and MC-YR, were quantified by ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS).
Results MCs were detected in the whole year (MC-LR was the main component), and the content ranged from ND to 16.3 ng/L with the highest concentration found in the August sample. The concentrations of MC-LR were over 10.0 ng/L in several months for some districts. Due to the diversity of water supply, MCs concentrations varied significantly. The minimum and maximum valuesof average MCs concentrations in the whole year were 0.2 and 6.7 ng/L respectively. The levels of individual health risk of drinking water ranged from (0.15& #215;10-6 to 5.62& #215;10-6)/a in the selected area. In most districts, the health risk values contributed by MCs were lower than the maximum allowance level recommended by ICRP (5& #215;10-5)/a and by US EPA (1& #215;10-4)/a.
Conclusion The diversity of water supply has generated differences in the contents of MCs in the districts investigated. Drinking water in most selected districts present certain health risks.
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