Occurrence of toxic cyanobacterial blooms in Rio de la Plata Estuary,Argentina: Field study and data analysis

Water samples were collected during 3 years (20042007) at three sampling sites in the rio de la plata estuary. thirteen biological,physical,and chemical parameters were determined on the water samples. the presence of microcystin-lr in the reservoir samples,and also in domestic water samples,was confirmed and quantified. microcystin-lr concentration ranged between 0.02 and 8.6g.l -1. principal components analysis was used to identify the factors promoting cyanobacteria growth. the proliferation of cyanobacteria was accompanied by the presence of high total and fecal coliforms bacteria (1500mnp/100ml),temperature ≥25()c,and total phosphorus content ≥1.24mgl -1. the observed fluctuating patterns of microcystis aeruginosa,total coliforms,and microcystin-lr were also described by probabilistic models based on the log-normal and extreme value distributions. the sampling sites were compared in terms of the distribution parameters and the probability of observing high concentrations for microcystis aeruginosa,total coliforms,and microcystin-lr concentration. copyright © 2012 l. giannuzzi et al.