Indiscriminate use of glyphosate impregnates river epilithic biofilms in southern Brazil

FERNANDES, GRACIELI; APARICIO, VIRGINIA CAROLINA; BASTOS, MARILIA CAMOTTI; DE GERÓNIMO, EDUARDO; LABANOWSKI, JÉRÔME; PRESTES, OSMAR DAMIAN; ZANELLA, RENATO; DOS SANTOS, DANILO RHEINHEIMER

THE SCIENCE OF TOTAL ENVIRONMENT

ELSEVIER

Año: 2019 vol. 651 p. 1377 - 1387

0048-9697

Epilithic biofilms are communities of microorganisms composed mainly of microbial cells, extracellular polymericsubstances from the metabolism of microorganisms, and inorganic materials. Biofilms are a useful toolto assess the impact of anthropic action on aquatic environments including the presence of pesticide residuessuch as glyphosate. The present work seeks to monitor the occurrence of glyphosate and AMPA residues inepilithic biofilms occurring in a watershed. For this, epilithic biofilm samples were collected in the GuaporéRiver watershed in the fall and spring seasons of 2016 at eight points. Physicochemical properties of the waterand biofilms were determined. The determination of glyphosate and AMPA was performed using an ultra-highperformance liquid chromatograph coupled to a tandem mass spectrometer. The concentrations of glyphosateand AMPA detected in epilithic biofilms vary with the season (from 90 to 305 μg kg−1 for glyphosate and from50 to 240 μg kg−1 for AMPA, in fall and spring, respectively) and are strongly influenced by the amount of herbicideapplications. Protected locations and thosewith poor access not demonstrate the presence of these contaminants.In the other seven points of the Guaporé River watershed, glyphosate was detected in concentrationsranging from 10 to 305 μg kg−1, and concentrations of AMPA ranged from 50 to 670 μg kg−1. An overview ofthe contamination in the Guaporé watershed shows that the most affected areas are located in the Marau subwatershed,which are strongly influenced by the presence of the city of Marau. This confirms the indiscriminate use of glyphosate in the urban area (weed control, domestic gardens and horticulture) and constitutes a problemfor human and animal health. The results showed that biofilms can accumulate glyphosate resulting from thecontamination of water courses and are sensitive to the sources of pollution and pesticides present in rivers.