Avaliação da qualidade de nascentes de água no refúgio da vida silvestre dos campos de Palmas

Abstract

Conservation Units play a strategic role in maintaining biodiversity and protecting water resources, ensuring essential ecosystem services for society. In this context, this study investigated the water and sediment quality of springs located in the Campos de Palmas Wildlife Refuge (RVS-CP), Paraná, considering the environmental impacts resulting from agricultural activities in the Southwest Mesoregion of Paraná. Samples were collected during a single campaign in May 2024 from springs N1, N2, and N3, totaling three water samples and three sediment samples. The analyses included physicochemical parameters (dissolved oxygen, pH, turbidity, total solids, BOD₅, nitrogen, and phosphorus), microbiological parameters (thermotolerant coliforms), macroscopic assessment (observation of color, odor, residues, and riparian vegetation), determination of the Water Quality Index (WQI), quantification of heavy metals (Al, Zn, Pb, Cu, Ni, among others), detection of pesticide residues, and ecotoxicological tests with the bioindicators A. cepa and E. fetida. The results indicated that springs N1 and N2 exhibited relatively preserved environmental conditions, with water quality indices classified as “excellent,” absence of thermotolerant coliforms, and low macroscopic degradation. In contrast, spring N3 showed significant environmental degradation, characterized by high turbidity, odor, and dark coloration of the water, in addition to the presence of solid waste and pesticide packaging. This spring presented a WQI classified as “good,” though at the lower threshold, reflecting greater anthropogenic pressure from intensive agricultural use, contributing to its poor state of conservation. Chemical analyses revealed elevated concentrations of aluminum and zinc in the water, suggesting influence from both natural soil characteristics and agricultural practices. In sediments, metals remained below legal limits, indicating lower accumulation in this matrix. However, pesticide residues were detected in both water and sediments from spring N3, with azoxystrobin and trifloxystrobin fungicides and thiamethoxam insecticide identified in the water, as well as carbendazim (a substance banned in Brazil by ANVISA), difenoconazole, tebuconazole, and trifloxystrobin in sediments. The cytotoxicity test with Allium cepa revealed significant changes in the mitotic index in water and sediment samples, especially from N3, suggesting effects related to the presence of metals and pesticides. The bioassay with Eisenia fetida indicated toxicity in specific sediments, evidencing soil sensitivity to contaminants. This study highlights the urgent need for interventions to restore spring N3 and to adopt conservation practices in the surroundings of the RVS-CP, including fencing, erosion control, riparian vegetation restoration, and restrictions on pesticide use in areas near springs. The results reinforce the importance of continuous water quality monitoring and the integration between environmental conservation and sustainable development, as advocated by the Sustainable Development Goals (SDG 6 – Clean water and sanitation; SDG 12 – Responsible consumption and production; SDG 14 – Life below water; SDG 15 – Life on land).