Environmental fragility as an indicator of the risk of contamination by human action in watersheds used for public supply in western Paraná, Brazil

Abstract

Applying environmental fragility in studies evaluating watershed can guide policy decisions on monitoring and management regarding soil use planning, improving water quality for public supply. The objective of this study is to characterize the environmental fragility as well as to relate it to water quality factors of catchment rivers for public supply in western Paraná, Brazil, in order to evaluate the in uence of anthropic actions on catchment sources. Water quality data such as temperature (Temp; C), electrical conductivity (Ec; mS/cm −1 ), dissolved oxygen (DO; mg L −1 ), turbidity (Turb; NTU) and pH were measured on site by the multi-parameter probe HORIBA brand, model U-5000. Slope data were obtained from the site of the National Institute of Space Research (INPE). Soil use and occupation was performed in the QGis software, with image obtained from the Sentinel 2A Satelite. Köppen-Geiger classi cation was used for the climate type. For the environmental fragility maps, the variables slope, climate, soil use and occupation were analyzed using the QGis raster software calculator. The intermediate fragility class predominates in the nine municipalities studied, making it necessary to manage them aimed at restoration and conservation, and the municipalities that are the largest areas of high fragility class are: Guaraniaçu, Catanduvas and Cascavel, demanding greater attention. The variation in fragility mainly responded to the pH, E. coli and DQO temperature values, which can be strongly associated with the difference in soil use and slope of the areas evaluated.

Main predictors of phytoplankton occurrence in lotic ecosystems

“…Studies conducted in the same watershed consolidated the effects of urbanization and agriculture on limnological variables (Medeiros et al, 2020). When assessing environmental fragility (calculation performed using slope, soil type, and landscape) Peres et al (2022) found that the watershed of the Cascavel River presents a high environmental fragility, being one of the most impacted in the western region of the state of Paraná, Brazil.…”

Taxonomic study and local environmental conditions of occurrence of Chlorophyceae (Chlorophyta) from subtropical lotic environments, Paraná, Brazil

“…Increasingly, lotic environments are degraded due to urbanization and intense anthropic activities (Li et al 2022). In this context the water for public supply is deteriorated, besides all aquatic biota that suffer the consequences of inadequate management of these environments (Peres et al 2022). In this sense the taxonomic composition of the Class Chlorophyceae is an important tool to assist in environmental diagnosis, since the species are often associated with environments with organic pollution and potential eutrophication (Wijeyaratne & Nanayakkara 2020).…”