Cyanobacteria and Fish: A Toxic Health Threat to Tribal Communities?

Noxious cyanobacteria (blue green algae) blooms have become a serious environmental problem worldwide.  Currently, there is indication that the prevalence and toxicity of cyanobacteria is intensifying throughout the United States due to increases in aquatic pollution.  Direct exposure or consumption of water with cyanotoxins is a known health hazard, but there is a fundamental gap in understanding trophic transfers and potential accumulation in aquatic animals such as fish.  For individuals in tribal and other communities that depend on local fish sources as a substantial part of their diet, toxin accumulation in fish may be of particular concern.  Our study addresses the most common cyanotoxin, the hepatotoxin microcystin, known to cause fatalities in humans, fish and domestic livestock.  We collected brook trout (Salvelinus Fontinalis) and rainbow trout (Oncorhynchus Mykiss) muscle tissue from four lakes on the Confederated Tribes of the Colville Reservation in northeastern Washington, where recent increase in cyanobacteria blooms have been noted.  Based on sound analytical procedures, preliminary studies have shown some accumulation of microcystin in trout muscle and that common cooking methods may enhance biological availability of the toxin.