Fig. 1

source to tap. Natural toxin () production by cyanobacteria and plants (cropland, forests, pasture, gardens), release and transfer to lake water and soils, transport via soils to groundwater and surface water reservoirs from which drinking water is abstracted. Molecular structures of ptaquiloside (left), senecionine (middle) and microcystin LR (right) illustrating the polar nature of natural toxins (cf Table 1)