The removal of microcystins in drinking water by clay minerals

Korean Yellow Clay (Whangto) can be used to efficiently remove the cyanobacterial toxin microcystin-LR when present in water. This removal technique can be employed by rural and remote communities when surface water is contaminated with a toxic Microcystis sp. bloom. In most cases two sequential applications of clay can bring the dissolved microcystin toxin content below WHO guidelines for drinking water (1 ug/L) (WHO, 1998). The removal process is characterised by adsorption to the clay particle, with the Langmuir isotherm fitting the results marginally better than the Freundlich isotherm.