Potentially Toxic Cyanobacteria and Quantification of Microcystin-LR and Cylindrospermopsine in Four Dams of Guanajuato, Mexico

The quality and availability of water are at risk due to the presence of cyanobacteria blooms capable of producing cyanotoxins. The purpose of this research was to determine their occurrence in four dams in Mexico. The most abundant cyanobacteria found were Planktothrix agardhii, Oscillatoria sp., Raphidiopsis sp., and Microcystis sp. Microcystin-LR levels presented values between 0.08-0.42 μg/L which are within the provisional guideline values (PGV) for human consumption in drinking water, but Cylindrospermopsin levels ranged from 0.02-2.05 μg/L exceed up to 3 times the PGV established by the WHO. They presented a pH of 6.1 to 8.4, an electrical conductivity of 121 to 415 μS/cm2, chlorophyll of 0.43-42.43 μg/L, NO3- 0-1.2 mg/L and PO43- 0.11 to 0.84 mg/L; considering these parameters, the dams most prone to the development of cyanobacterial blooms were the El Palote, La Purísima, and Allende dams, but not El Conejo dam. This work is relevant due to the use of these bodies of water for agriculture and human consumption in the state of Guanajuato in Mexico. The presence of toxin-producing cyanobacteria in these dams represents an environmental, ecotoxicological, and health risk so it is recommended to establish a permanent program for monitoring cyanobacteria and cyanotoxins.