Uso de pesticidas: uma ameaça aos peixes do Rio Poti no semiárido cearense

Abstract

The increasing use of pesticides in agriculture, especially triazines and organophosphates, is a warning regarding their effects on aquatic ecosystems, particularly in the semiarid region of Ceará, which is affected by climate change. This study aims to evaluate the presence and effects of these contaminants on the health of fish in the Poti River (CE), in and around the Boqueirão Environmental Protection Area (APA). Samples were collected in the districts of Ibiapaba and Oiticica. The methodology consisted of studying the presence and concentration of contaminants belonging to the triazine and organophosphate classes using gas chromatography and calculating fish health indices: Hepatosomatic Index (HIS), Gonadosomatic Index (GSI), Gastrosomatic Index (GII), and Condition Factor (CF). The results of the chromatographic analyses revealed the presence of atraton, symmetryn, malathion, and chlorpyrifos, which are compatible with pesticides. Health index values revealed that pesticide contamination can be exacerbated by rising temperatures and rainfall shortages, affecting the locomotor system, nutritional status, and body condition, as well as the reproductive capacity of some of the fish studied. Histological analysis of the liver revealed alterations such as melanomacrophages, vacuolization, and necrosis in individuals from both locations, the latter being the most severe and generally irreversible. Statistical, chromatographic, and histological studies, both inside and outside the APA, revealed that the distribution of contamination among the species is similar, demonstrating the persistence of the pollutants. Finally, it can be concluded that the chronic effects of pesticide exposure, combined with the effects of climate change, can compromise fish health and endanger the local aquatic biodiversity.