RESUMO
The objective of this study was to evaluate the occurrence of pesticides in surface and groundwater of agricultural areas of the Pampas region of Argentina and to develop an ecological risk assessment (ERA) of pesticides in freshwater ecosystems. Eight agricultural sites from south Santa Fe province, in the north of the Pampas region, were sampled seven times between 2016 and 2018. Pesticides were analysed by gas chromatography-mass spectrometry (GC/MS) and liquid chromatography-mass spectrometry (UPLC-LC/MS). Twenty compounds among herbicides, insecticides and fungicides in 84% and 79% of groundwater and surface water samples, respectively, were detected. Atrazine was the most ubiquitous pesticide, following by metolachlor, acetochlor and glyphosate, with maximum concentrations of 28, 24, 77 and 111 µg/L, respectively. An ERA was performed by employing the risk quotient (RQ) method. Atrazine, azoxystrobin, pirimiphos-methyl, acetochlor and epoxiconazole posed a high and very high risk for aquatic organisms (RQ > 1) and glyphosate, metolachlor and 2,4-D exhibited negligible to medium risk. The herbicides were the major contributors to risk. This study is the first contribution on the presence and concentration of pesticides in surface and groundwater from agricultural areas of south Santa Fe province, north Pampas region, Argentina, and a starting point for pesticide ecological risk assessment.
Assuntos
Água Subterrânea , Praguicidas , Poluentes Químicos da Água , Argentina , Ecossistema , Monitoramento Ambiental , Praguicidas/análise , Medição de Risco , Poluentes Químicos da Água/análiseRESUMO
The aim of this study was to characterize the level and nature of the pesticide contamination received by one-sided livebearer fish (Jenynsia multidentata) from a watercourse situated within the main agricultural region of Argentina, and to assess the effects of this contamination on fish health. Juvenile one-sided livebearer fish (Jenynsia multidentata) were collected in December 2011 and March 2012 from three sites along the Pergamino River. Pesticide contamination was characterized by extracting whole fish and analytically determining thirty different pesticide molecules. The biomarkers catalase, glutathione-S-transferase, and cholinesterases were assessed. Body condition was calculated as an estimate of the amount of energy reserves possessed by the fish. Seventeen different pesticides were detected in fish tissues with 81% of captured animals containing at least one pesticide molecule. The pyrethroid insecticides fenvalerate and bifenthrin were most frequently detected, being respectively found in 41.8 and 36.4% of samples tested. Highly toxic dichlorvos and pirimiphos-methyl were detected. Differential levels of contamination could not be established amongst sites but were observed within sites amongst the two sampling dates. The months when pesticide residues were most abundant from in Site A and B corresponded to the months when body condition was at its lowest in the two sites. The inhibition of Che activity in March when body condition was reduced also points to a role of insecticide contamination in the reduction of body condition. These findings provide strong new evidence that current-used agricultural pesticides can accumulate in wild fish and impact their health and energetics.