THE FIRST REPORT OF A MICROCYSTIN-PRODUCING CYANOBACTERIA BLOOM IN PARANOÁ LAKE, BRASÍLIA, BRAZIL

SILVA V. M. A. (1), SCHWARTZ C. A.(1), OLIVEIRA, N.B.(1),  MACHADO M. G.(2), MELO J. A. T. (3), BLOCH JR C.(3), PIRES JÚNIOR O.R.(1).

(1) Laboratório de Toxinologia, Departamento de Ciências Fisiológicas, IB-UnB; (2) Laboratório de Ficologia-Herbário, Departamento de Botânica, IB-UnB; (3) Laboratório de Espectrometria de Massa, EMBRAPA-CENARGEN.

Cyanobacteria blooms occurring all around the world to increase the concern about the water quality used for consumption and recreation. Studies in Brazil reveal cases of cyanotoxins contamination in reservoirs, from the south to the northeast, evidencing the amplitude of occurrence of cyanobacteria. No study of cyanobacteria related to toxicity has already been carried out at Paranoá Lake, a reservoir destined to recreation and power production. Preliminary analyses demonstrated the occurrence of a cyanobacteria bloom , beginning in September and occurring until March of 2005 in the region of the Bananal branch. The toxin was identified by comparison with MCYST-LR, based on retention times, PDA-UV and MS spectral data. Using this approach it was possible to show that the cyanobacterial cells collected from the Paranoá Lake contained the most toxic microcystin-LR.

KEY WORDS: cyanotoxins, microcystin, Microcystis, Paranoá Lake.

FINANCIAL SUPPORT: CNPq.

CORRESPONDENCE TO: CARLOS ALBERTO SCHWARTZ, Laboratório de Toxinologia, Instituto de Biologia, Universidade de Brasília. Phone: 61 3307 2160. Fax:  61 3274 1251. Email: schwartz@unb.br