Passive Biomonitoring of La Brava lagoon (Argentina) using the fish Oligosarcus jenynsii

LOMBARDERO LUCAS RODRIGO; ITURBURU FERNANDO GASTÓN; MEDICI, SANDRA; CRUPKIN ANDREA CARINA; VILLAGRAN DIANA; PÉREZ DÉBORA JESABEL; MENONE MIRTA LUJÁN

Panamá

Workshop; 8th Latin American Pesticide Residue Workshop; 2021

La Brava lagoon is a site protected by the Agency for Sustainable Development (OPDS) in Argentina. Despite of this status it is surrounded by extensive agriculture. The aim of this study was to evaluate the influence of agriculture by means of the effect of oxidative stress in O. jenynsii, a fish species representative of this ecosystem. Two samplings were carried out during one year; one in spring (2019), when the application of agrochemicals has just started, and another in summer (2020), during the maximum application of chemical compounds. Twenty fish and surface water samples (n=3) were taken in each sampling. The fish were measured and weighted, also, the liver of each organism was weighed, in order to obtain the condition index (K) and the hepatosomaticindex (HIS). The activities of the enzymes Catalase (CAT) and Glutathione S transferase (GST) were measured, as well as the levels of Malondialdehyde (MDA) in liver, gill and brain, all spectrophotometrically. Water samples were analyzed by UPLCMS/MS (Waters Xevo TQS-microTM) to quantify current use pesticides. The results showed that levels of Glyphosate and Chlorpyrifos remained constant in these two sampling periods. AMPA and Imidacloprid were only found in summer. Both, the K and HIS indices were lower in summer than in spring. An increase of 581% in CAT activity from liver and 597% from gills in summer with respect to spring time was observed.Likewise, GST increased in liver 159% and no significant changes in MDA levels were detected between both seasons. These results show the role of antioxidant enzymes in fish, since oxidative stress damage was not observed in terms of lipid peroxidation, may be due to the increase of the antioxidant enzyme activities. The results found for the liver and gills are consistent, since liver is the main detoxifying organ and gills are the organ with the highest exposure to agrochemicals1. In this way, biomarkers of oxidative stress in target organs are able to show the effects of some of the most used pesticides in the region.