Cyanotoxins in the Environment
Harmful algae blooms and their associated cyanotoxins are an increasing global issue that poses an environmental and human health hazard. Cyanobacteria (blue-green algae) are a diverse assemblage of aquatic bacteria that can occur in blooms large enough to produce harmful quantities of cyanotoxins, which can be moderately to severely toxic to humans. With increasing populations and agriculture, more water used for drinking and irrigation could come from cyanotoxin-infected sources. A local example is Utah Lake, whose distributary river, the Jordan River, is used by farmers and residents for crop irrigation. Several globally common cyanotoxin compounds have been measured in Utah Lake in recent years, including hepatoxic microcystin and nodularin, and neurotoxic B-methylamino-L-alanine (BMAA), which is ubiquitous to cyanobacteria and can bio-magnify up to 100-fold. The presence of these toxins in water bodies like Utah Lake and the Jordan River may pose a threat to humans who use the contaminated water for crop and garden irrigation. We lack experimental data on the fate of these toxins in the environment, and particularly on the capacity for food crops to bioaccumulate cyanotoxins. Studies to date are short (<10 days), have studied microcystin exclusively, and have relied on spray irrigation. Although this work has shown that toxins accumulate on crop surfaces, a more compelling question is whether plants, and different plant parts, can take up and store toxins within their tissues. Information on cyanotoxins other than microcystin is lacking, as are standardized methods to extract and quantify these toxins in environmental samples. Moreover, basic partition coefficients have not yet been derived. I plan to fill these significant knowledge gaps by 1) determining an efficient procedure for extracting and analyzing cyanotoxins from vegetables and soils, 2) calculating soil organic carbon to water partition coefficients, and 3) quantifying cyanotoxin uptake in common vegetables grown in cyanotoxin-laced water.