Potential Exposure to Cyanotoxins while Recreating, and Seasonally Dynamic Indicators of Microcystin Production

Abstract

Cyanobacteria form harmful algal blooms (cHABs) and certain species can produce variable cyanotoxins, specifically the most common and toxic, Microcystin (MC) and its associated congeners. Cyanotoxins and MC in cHABs often reach concentrations that are deemed unsafe for human consumption and recreation. Recreational activities during cyanobacterial blooms can expose a person to a high cyanotoxin concentrations. I hypothesized that persons engaged in motorized recreational activities during cyanobacterial blooms will be exposed to measurable cyanotoxin concentrations without full-body immersion. I constructed a device to be towed behind a motorboat, and 10 sampling events occurred at Chautauqua Lake, a eutrophic lake with reoccurring cHABs. Splash collected contained 0.02 – 4.1 µg L⁻¹ of total microcystins (MC) by LC-MS/MS and was highly correlated to the lake surface concentration (R² = 0.95, p < 0.05). Surface MC was significantly correlated to the interaction of water temperature and Microcystis aeruginosa abundance (R² = 0.92, p < 0.05), over the traditionally used indicators total cyanobacterial abundance, chlorophyll a, and warm water. These results show certain recreational activities may expose a person to unsafe MC concentrations from splash contact alone, and limnological conditions surrounding MC production can vary between systems.