OCCURRENCE AND TOXICITY OF CYANOBACTERIAL BLOOMS IN PARANÁ RIVER (ARGENTINA), DOWNSTREAM OF THE YACYRETÁ RESERVOIR

FORASTIER MARINA E.; ZALOCAR DE DOMITROVIC YOLANDA; SEDAN DANIELA; ANDRINOLO DARIO

Estambul

Conferencia; 8th International Conferene on Toxic Cyanobacteria; 2010

The Paraná river basin is the second largest catchment of South America, shared by Brazil, Bolivia, Paraguay and Argentina. The construction of Yacyretá on High Paraná, one of the largest impoundments built in Argentina, was finished in 1990-1994. To ten years of Yacyretá functioning, in summer of 2004, were registered the first bloom of Microcystis aeruginosa (Kütz.) Kütz in the river Paraná. In this work we presents a study of abundance and toxicity of  blooms of  M. aeruginosa 220 km downstream from the reservoir Yacyretá (27 º 28 ´ 16 " S; 58 º 51 ´ 07 " O) between the year 2004 and 2008. For the study of the phytoplankton, were taken monthly qualitative and quantitative samples.  To determinate toxicity, the samples were taken in summer, from the year 2005 until 2008. This samples were tested by mouse biossay and igh- performance liquid chromatografy (HPLC) whith diode-array. The major density of M. aeruginosa was in summer all years, (with 189-3x104 cél.ml-1), and with  mean volume of 5 mm3.L-1. The analyses of the samples presented higher hepatotoxicity in the tests with mice. Five variants were detected of microcystins: LR, LA, RR, YR and XR. LR was better represented every year in concentrations between 3 and 185 ppm of lyophilised cells. This is the first report of microcystins in the Paraná river (Argentina) during blooms de M. aeruginosa.