Journal of Applied Phycology

, Volume 22, Issue 3, pp 235–241

Occurrence of anatoxin-a(s) during a bloom of Anabaena crassa in a water-supply reservoir in southern Brazil

  • Vanessa Becker
  • Priscila Ihara
  • João Sarkis Yunes
  • Vera Lúcia M. Huszar
Article

DOI: 10.1007/s10811-009-9451-8

Cite this article as:
Becker, V., Ihara, P., Yunes, J.S. et al. J Appl Phycol (2010) 22: 235. doi:10.1007/s10811-009-9451-8

Abstract

Cyanobacterial blooms and the accompanying production of cyanotoxins are a serious global problem. Toxic blooms of Anabaena species are common in lagoons and reservoirs of southern Brazil. Worldwide, species of the genus Anabaena produce the majority of the known hepatotoxins (microcystins) and neurotoxins [anatoxin-a, anatoxin-a(s), and saxitoxins]. This report links a bloom of Anabaena crassa in the Faxinal Reservoir, the main water supply for the city of Caxias do Sul (400,000 inhabitants) in southern Brazil, to the occurrence of anatoxin-a(s) in the water. During the bloom period, the reservoir was strongly stratified, with higher temperatures and a deep anoxic hypolimnion. Two methods for sample concentration (direct and complete extraction) were tested, and direct extraction of samples proved to be more efficient. Water samples collected during the bloom showed 9% acetylcholinesterase inhibition at 50 mg mL−1, corresponding to 0.61 μg of anatoxin-a(s) per gram of lyophilized powder. At these concentrations, symptoms of neurotoxicity and mortality were not observed in tests with Swiss albino mice. Although the concentrations of anatoxin-a(s) in the Faxinal Reservoir were low, these results are important because this is the first record of the toxin for A. crassa. Furthermore, this cyanotoxin is not yet included in Brazilian legislation for drinking-water monitoring, because of the lack of information about toxicity levels and risk calculation for oral doses. The data presented here contribute to the basis for the future inclusion of this toxin in Brazilian legislation for drinking-water quality control, and for the development of analytical methods for this toxin.

Keywords

Acetylcholinesterase Cyanobacteria Cyanotoxin Subtropical 

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  • Vanessa Becker
    • 1
    • 3
  • Priscila Ihara
    • 2
  • João Sarkis Yunes
    • 2
  • Vera Lúcia M. Huszar
    • 1
  1. 1.Laboratory of Phycology, Museu Nacional do Rio de JaneiroUniversidade Federal do Rio de JaneiroSão CristovãoBrazil
  2. 2.Unidade de Pesquisa em Cianobactérias, Prédio da Hidroquímica—Instituto de OceanografiaUniversidade Federal do Rio GrandeRio GrandeBrazil
  3. 3.Water Resources and Sanitary Engineering Post Graduate Program, Instituto de Pesquisas HidráulicasUniversidade Federal do Rio Grande do SulPorto AlegreBrazil

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