Integrating multiple lines of evidence to assess freshwater ecosystem health in a tropical river basin. (15th November 2021)

• Record Type: Journal Article
• Authors: Chancay, Juseth E.; Lucas-Solis, Oscar; Alvear-S, Daniela; Martínez-R, Dayana; Mena, Gisella; Zurita, Bryan; Carrasco-S, Luis; Carrillo, Henry; Segarra, Víctor; Naranjo, Elizabeth; Coronel, Brian; Espinosa, Rodrigo; Cabrera, Marcela; Capparelli, Mariana V.; Celi, Jorge E.
• Is Part Of: Environmental pollution. Volume 289(2021)
• Publication Date: 2021-11-15
• Subjects: Ion pollution -- Organophosphate pesticides -- Phytotoxicity -- Agricultural impacts -- IFEQ index; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2021.117796
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Degradation of freshwater ecosystems by uncontrolled human activities is a growing concern in the tropics. In this regard, we aimed at testing an integrative framework based on the IFEQ index to assess freshwater ecosystem health of river basins impacted by intense livestock and agricultural activities, using the Muchacho River Basin (MRB) as a case study. The IFEQ combine multiple lines of evidence such as riverine hydromorphological analysis (LOE 1), physicochemical characterization using ions and pesticides (LOE 2), aquatic macroinvertebrate monitoring (LOE 3), and phytotoxicological essays with L. sativa (LOE 4). Overall, results showed an important reduction in streamflow and an elevated increase in ion concentrations along the MRB caused by deforestation and erosion linked to agricultural and livestock activities. Impacts of the high ion concentrations were evidenced in macroinvertebrate communities as pollution-tolerant families, associated with high conductivity levels, represented 92 % of the total abundance. Pollution produced by organophosphate pesticides (OPPs) was critical in the whole MRB, showing levels that exceeded 270-fold maximum threshold for malathion and 30-fold for parathion, the latter banned in Ecuador. OPPs concentrations were related to low germination percentages of Lactuca sativa in sediment phytotoxicity tests. The IEFQ index ranged from 44.4 to 25.6, indicating that freshwater ecosystem conditions were "bad" at the headwaters of the MRB and "critical" along the lowest reaches. Our results show strong evidence that intense agricultural and livestock activities generated significant impacts on the aquatic ecosystem of the MRB. This integrative approach better explains the cumulative effects of human impacts, and should be replicated in other basins with similar conditions to help decision-makers and concerned inhabitants generate adequate policies and strategies to mitigate the degradation of freshwater ecosystems. Graphical abstract: Image 1 Highlights: Hydromorphological conditions and streamflow greatly decrease downstream. High Li+, Br-, and F- concentrations attributed to diffuse agricultural sources. Malathion concentration exceeded 270-fold the maximum threshold. Elevated phytotoxicity levels were associated to critical pesticide pollution. The integrative framework better captured cumulative effects of anthropic impacts.