Dissolved microcystins in surface and ground waters in regions with high cancer incidence in the Huai River Basin of China

Microcystins (MCs) are potent hepatotoxins and have also implicated in liver tumor promotion. The present study investigates the temporal and spatial variations of MCs in different water bodies in the Huai River Basin in China. Water samples including rivers, ponds and wells were collected every quarter during December 2008 and December 2009. MCs were determined by high pressure liquid chromatography after solid phase extraction. MCs concentrations in river samples were 0.741 ± 0.623 μg L−1 with maximum of 1.846 μg L−1. MCs in pond were 0.597 ± 0.960 μg L−1 with maximum of 2.298 μg L−1. MCs were also detected in 51.7% of the groundwater samples, MCs in groundwater were 0.060 ± 0.085 μg L−1 with maximum of 0.446 μg L−1. MCs concentrations in groundwater did not differ significantly among different depths or towns (Wilcoxon test, p > 0.05). The average MCs in groundwater in each sampling period were 0.068 μg L−1, 0.118 μg L−1, 0.052 μg L−1, 0.059 μg L−1 and 0.020 μg L−1. Through multi linear regression, the best fit model was built on MCs in groundwater with River B (R2 = 0.13, p < 0.05), rather than with pond water. The results suggested that MCs contamination in groundwater originated from rivers, causing potential health risk on population who drink groundwater directly.

► The first study on microcystins pollution in groundwater in Huai River Basin.
► Quantify linear relation of microcystins between rivers and groundwater.
► Providing the evidence that MCs in groundwater from the river replenishment.
► Microcystin-RR as the most dominant toxin in groundwater.