Integrating water, sediments, and land use analysis for pollution assessment in a countryside urban-farming watershed landscape in southern Brazil

Abstract

ABSTRACT Integrating water and sediment analysis with land use brings significant results in understanding the transformations in the watershed and assessing anthropic actions. We assess water and sediment samples collected in four sites in a countryside urban-farming watershed landscape in Southern Brazil. We performed the land-use, physical–chemical, microbiological, potentially toxic element (Pb, Cd, Zn, Cu, Ni, and Cr), atrazine, 2.4-D, microbiological contamination analysis, and total organic carbon, nutrients, and granulometry. We also calculate the Water quality index, geoaccumulation index, enrichment factor, and ecological risk potential, with SQGs (TEL and PEL). Our results demonstrate that all the water samples of this study were contaminated with faecal and total coliforms, alerting the effectiveness of treatment at these plants. We found no significant concentrations of pesticides in the water. The concentration of metals in the sediment was in the order of Cu > Zn > Cr > Ni > Pb > Cd, with Igeo = 0–3 for Cu, Zn, and EF < 3 for Cu. The Cu concentration was eight times higher than TEL, Cr, and Cu above TEL at all sites. We found a strong positive correlation between atrazine, 2.4-D, Pb, and nutrients from agricultural activities and higher concentrations at the one site. The Zn, Cu, Ni, Cd, and Cr sources were plantations, forests, and domestic sewage discharges. The results corroborate with the proposition that complete assessments of watersheds including analyses of water, sediment, and land uses are necessary to understand the real effects of anthropic action on this ecosystem and diversity of this environmental.