Epilithic biofilms, POCIS, and water samples as complementary sources of information for a more comprehensive view of aquatic contamination by pesticides and pharmaceuticals in southern Brazil

Abstract

Spatial-temporal monitoring of the presence of pesticides and pharmaceuticals in water requires rigor in the choice of matrix to be analyzed. The use of matrices, isolated or combined, may better represent the real state of contamination. In this sense, the present work contrasted the effectiveness of using epilithic biofilms with active water sampling and with a passive sampler—POCIS. A watershed representative of South American agriculture was monitored. Nine sites with different rural anthropic pressures (natural forest, intensive use of pesticides, and animal waste), and urban areas without sewage treatment, were monitored. Water and epilithic biofilms were collected during periods of intensive pesticide and animal waste application. After the harvest of the spring/summer crop, a period of low agrochemical input, the presence of pesticides and pharmaceuticals was monitored using the POCIS and epilithic biofilms. The spot water sampling leads to underestimation of the level of contamination of water resources as it does not allow discrimination of different anthropic pressures in rural areas. The use of endogenous epilithic biofilms as a matrix for the analysis of pesticides and pharmaceuticals is a viable and highly recommended alternative to diagnose the health of water sources, especially if associated with the use of POCIS.

Keywords:

• Catchment
• erosion
• runoff
• subtropical agriculture
• water quality

Disclosure statement

All participants declare that they have contributed substantially to research design, the acquisition, analysis, interpretation of data, drafting the paper, revising it critically, and have approved the submitted and final versions. All listed authors meet these criteria and nobody who qualifies for authorship has been excluded. We declare that the submitted work has not been published previously in full and is not being considered for publication elsewhere.

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Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

This study was supported by CAPES‐COFECUB (Project 3504-11-5, 761/12), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Finep/FEPAGRO (Project MAIS AGUA), Europen Communities (FEDER), and Région Nouvelle Aquitaine.