Occurrence of microcystins in lakes in the contiguous US 48 states
United States occurrence of microcystins in lakes in the contiguous 48 U.S. states categorized by World Health Organization relative probable health risk. WHO low, moderate, and high refer to the relative human recreational health thresholds for microcystin exposure. Map not shown to scale. Modified from figure 2 from Loftin and others, 2016.