posted on 2020-03-30, 21:03authored byNicole
E. Olson, Madeline E. Cooke, Jia H. Shi, Johnna A. Birbeck, Judy A. Westrick, Andrew P. Ault
Harmful
algal blooms (HABs) caused by cyanobacteria in freshwater
environments produce toxins (e.g., microcystin) that are harmful to
human and animal health. HAB frequency and intensity are increasing
with greater nutrient runoff and a warming climate. Lake spray aerosol
(LSA) released from freshwater lakes has been identified on lakeshores
and after transport inland, including from lakes with HABs, but little
is known about the potential for HAB toxins to be incorporated into
LSA. In this study, freshwater samples were collected from two lakes
in Michigan: Mona Lake during a severe HAB with microcystin concentrations
(>200 μg/L) well above the Environmental Protection Agency
(EPA)
recommended “do not drink” level (1.6 μg/L) and
Muskegon Lake without a HAB (<1 μg/L microcystin). Microcystin
toxins were identified in freshwater, as well as aerosol particles
generated in the laboratory from Mona Lake water by liquid chromatography–tandem
mass spectrometry (LC–MS/MS) at atmospheric concentrations
up to 50 ± 20 ng/m3. Enrichment of hydrophobic microcystin
congeners (e.g., microcystin-LR) was observed in aerosol particles
relative to bulk freshwater, while enrichment of hydrophilic microcystin
(e.g., microcystin-RR) was lower. As HABs increase in a warming climate,
understanding and quantifying the emissions of toxins into the atmosphere
is crucial for evaluating the health consequences of HABs.