First Report of Microcystins and Anatoxin-a Co-occurrence in San Roque Reservoir (Córdoba-Argentina).

RUIZ SMANIA, M.; GALANTI, L.N.; RUIBAL, A.L.; RODRIGUEZ, M.I.; WUNDERLIN D.A.; AMÉ, M. V.

WATER AIR AND SOIL POLLUTION

SPRINGER

Lugar: Berlin; Año: 2013 vol. 224 p. 1 - 17

0049-6979

Abstract The aim of this study was to evaluate the presence of microcystin-LR, microcystin-RR, microcystin-YR, and the neurotoxin anatoxin-a in water samples collected monthly during 1 year in San Roque reservoir (Córdoba, Argentina) to iden¬tify the environmental factors that could promote the presence of these cyanotoxins. The HPLC-UV and MS/MS analysis showed the presence of microcystin in most of the sampling times, even when Cyanobacteria were subdominant. Microcystin concentrations varied from not detectable levels to 119.0 (o.g L ´. Thus, they frequently surpassed the guidelines suggested by WHO for drinking water (1 (o.g L x) and recreational exposure (20 ig L 1). To the extent of our knowledge, this is the first report of anatoxin-a in freshwaters in South America. Anatoxin-a concentrations varied from not detectable levels to 6.6 ng L 1, a thousand times below the provisional guideline adopted by New Zealand for drinking water. Microcystin showed significant correlation with Microcystis and Pseudoanabaena while anatoxin-a cor¬related with Oscillatoria and Anabaena counts. Linear discriminant analysis showed that higher pH levels and more variable chlorophyll-a concentrations were mea¬sured in San Roque reservoir when cyanotoxins were present. Lower inorganic nitrogen concentrations were observed in autumn, when the prevalence of Anabaena became significant in Cyanobacteria composition and highest anatoxin-a levels were measured. The observed dynamic of phytoplankton going together with the cyanotoxins occurrence could be explained by the hy¬pothesis of cyanotoxins acting as allelopathic com¬pounds. The microcystin levels measured plus the presence of anatoxin-a show the need of stronger man¬agement efforts to preserve human and wildlife health.