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The efficiency of combined coagulant and ballast to remove harmful cyanobacterial blooms in a tropical shallow system.

  • Miranda, Marcela1
  • Noyma, Natália2
  • Pacheco, Felipe S3
  • de Magalhães, Leonardo2
  • Pinto, Ernani4
  • Santos, Suzan2
  • Soares, Maria Fernanda A5
  • Huszar, Vera L6
  • Lürling, Miquel7
  • Marinho, Marcelo M2
  • 1 Post-Graduate Program in Ecology, Federal University of Juiz de Fora, R. José Lourenço Kelmer, Juiz de Fora, MG 36036-330, Brazil. Electronic address: [email protected] , (Brazil)
  • 2 Laboratory of Ecology and Physiology of Phytoplankton, Department of Plant Biology, University of Rio de Janeiro State, Rua São Francisco Xavier 524 - PHLC Sala 511a, 20550-900 Rio de Janeiro, Brazil. , (Brazil)
  • 3 Earth System Science Center (CCST), National Institute for Space Research (INPE), Av. dos Astronautas, 1.758 - Jardim da Granja, 12227-010 São José dos Campos, SP, Brazil. , (Brazil)
  • 4 Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 580 - Bl 17, 05508-900 São Paulo, SP, Brazil. , (Brazil)
  • 5 Post-Graduate Program in Ecology, Federal University of Juiz de Fora, R. José Lourenço Kelmer, Juiz de Fora, MG 36036-330, Brazil. , (Brazil)
  • 6 Laboratory of Phycology, National Museum, Federal University of Rio de Janeiro 20940-040, Rio de Janeiro, Brazil. , (Brazil)
  • 7 Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands. , (Netherlands)
Published Article
Harmful algae
Publication Date
May 01, 2017
DOI: 10.1016/j.hal.2017.04.007
PMID: 28526117


We tested the hypothesis that a combination of coagulant and ballast could be efficient for removal of positively buoyant harmful cyanobacteria in shallow tropical waterbodies, and will not promote the release of cyanotoxins. This laboratory study examined the efficacy of coagulants [polyaluminium chloride (PAC) and chitosan (made of shrimp shells)] alone, and combined with ballast (lanthanum modified bentonite, red soil or gravel) to remove the natural populations of cyanobacteria collected from a shallow eutrophic urban reservoir with alternating blooms of Cylindrospermopsis and Microcystis. PAC combined with ballast was effective in settling blooms dominated by Microcystis or Cylindrospermopsis. Contrary to our expectation, chitosan combined with ballast was only effective in settling Cylindrospermopsis-dominated blooms at low pH, whereas at pH≥8 no effective flocculation and settling could be evoked. Chitosan also had a detrimental effect on Cylindrospermopsis causing the release of saxitoxins. In contrast, no detrimental effect on Microcystis was observed and all coagulant-ballast treatments were effective in not only settling the Microcystis dominated bloom, but also lowering dissolved microcystin concentrations. Our data show that the best procedure for biomass reduction also depends on the dominant species. Copyright © 2017 Elsevier B.V. All rights reserved.

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