Quantification and detection of the algal toxin microcystin in water, sediment and tissue

Microcystins are hepatotoxins produced by Microcystis spp. and some other species of cyanobacteria. The World Health Organizations has set a guideline of 1 mug/L for microcystin-LR in drinking water and cyanobacteria has been placed on the EPA's contaminant candidate list. The first portion of this research aimed to identify and quantify Microcystis and the associated toxins in source waters in Florida and Michigan. The second portion of this research evaluated existing methods and new techniques for toxin detection, including Enzyme-Linked ImmunoSorbent Assay (ELISA) and Polymerase Chain Reaction (PCR). This research also analyzed methods to effectively extract toxins from sediments and tissues. Cyanobacteria and the toxin microcystin were both present in Florida waters, with Microcystis and Anabaena as the dominant cyanobacteria. Toxin levels remained steadily low throughout the sample period, with the exception of Lake Monroe (max. concentration = 2176 ng/L). Evaluation of Michigan Lakes found approximately three times higher concentration of microcystin in lakes containing zebra mussels, than lakes without zebra mussels. Laboratory studies identified ELISA and PCR as good analytical tools for the evaluation of toxins levels and the presence of genes indicating possible toxin production. Preliminary studies of toxin extraction methods from tissue and sediments gave a basis for further evaluation of procedures to improve recovery efficiencies.