Composition and toxic potential of cyanoprokaryota in vacha dam (bulgaria)

Abstract

Some species of Cyanoprokaryota produce toxins that affect animals and humans. Most of the freshwater basins in Bulgaria, including dams, are relatively well studied in terms of the phytoplankton composition, but the data for presence of cyanotoxins are limited. The aim of our study was to evaluate the diversity, distribution and quantitative development of the phytoplankton as well as the presence of cyanotoxins in the public reservoir Vacha. We have collected water and phytoplankton samples from Vacha reservoir at different time points. All water samples were analyzed for presence of cyanotoxins by ELISA, and tested for cytotoxicity on cell cultures in vitro. Physicochemical parameters, including water temperature, pH, total nitrogen and total phosphorus were measured. Algae, belonging to seven divisions (Cyanoprokaryota, Chlorophyta, Xantophyta, Dinophyta, Euglenophyta, Bacillariophyta and Criptophyta) were identified. A potentially toxic cyanoprokaryote Aphanizomenon flosaquae was detected in blooming concentrations in July and August 2008 as well as in July 2009 together with Microcystis aeruginosa. The water sample collected in August 2008 contained 0.25 ppb microcystins/nodularins. The total microcystins/nodularins concentration in the water samples collected in September 2009 was 0.5 ppb. The viability of HeLa cells was affected mainly after 48 h of exposure to the collected water samples. © 2010 Taylor and Francis Group, LLC.