Original Research ARTICLE
Occurrence of harmful cyanobacteria in drinking water from a severely drought-impacted semi-arid region
- 1Biology, Universidade Federal do Rio de Janeiro, Brazil
- 2Immunoregulation Unit, Instituto Butantan, Brazil
- 3Instituto de Pesquisa Professor Joaquim Amorim Neto, IPESQ, Brazil
- 4Secretaria de Saúde de Campina Grande, Brazil
- 5State University of Norte Fluminense, Brazil
- 6Universidade Federal do Rio de Janeiro, Brazil
Harmful cyanobacterial blooms have become increasingly common in freshwater ecosystems in recent decades, mainly due to eutrophication and climate change. Water becomes unreliable for human consumption. Here we report a comprehensive study carried out to investigate the water quality of several Campina Grande reservoirs. Our approach included metagenomics, microbial abundance quantification, ELISA test for three cyanotoxins (microcystin, nodularins and cylindrospermosin), and in vivo ecotoxicological tests with zebrafish embryos. Cytometry analysis showed high cyanobacterial abundance, while metagenomics identified an average of 10.6% of cyanobacterial sequences, and demonstrated the presence of Microcystis, Cylindrospermopsis and toxin coding genes in all ponds. Zebrafish embryos reared with pond water had high mortality and diverse malformations. Among the ponds analyzed, Araçagi showed the highest lethality (an average of 62.9% ± 0.8), followed by Boqueirão (lethality average of 62.5% ± 0.8). Here, we demonstrate that water from ponds undergoing extremely drought conditions have an abundance of potentially harmful cyanobacteria and their toxins. Our findings are consistent with a scenario in which polluted drinking water poses a great risk to human health.
Keywords: Cyanotoxins, Zebrafish, Metagenomics, Public Health, Eutrophication
Received: 10 Oct 2017;
Accepted: 25 Jan 2018.
Edited by:Sandra M. Azevedo, Universidade Federal do Rio de Janeiro, Brazil
Reviewed by:Richard A. White III (Rick White), UBC, Canada
Anna Barra Caracciolo, Consiglio Nazionale Delle Ricerche (CNR), Italy
Copyright: © 2018 Walter, Lopes, Lopes-Ferreira, Vidal, Leomil, Melo, Azevedo, Oliveira, Medeiros, Melo, De Rezende, Tanuri and Thompson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Fabiano L. Thompson, FT., Universidade Federal do Rio de Janeiro, Biology, Rio de Janeiro, Brazil, email@example.com