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

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

Workshop; 8° Latin American Pesticide Residues Worshop; 2021

Latin American Pesticide Residues

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 effectof oxidative stress in O. jenynsii, a fish species representative of this ecosystem. Twosamplings were carried out during one year; one in spring (2019), when the applicationof agrochemicals has just started, and another in summer (2020), during the maximumapplication of chemical compounds. Twenty fish and surface water samples (n=3) weretaken in each sampling. The fish were measured and weighted, also, the liver of eachorganism was weighed, in order to obtain the condition index (K) and the hepatosomaticindex (HIS). The activities of the enzymes Catalase (CAT) and Glutathione Stransferase (GST) were measured, as well as the levels of Malondialdehyde (MDA) inliver, gill and brain, all spectrophotometrically. Water samples were analyzed by UPLCMS/MS (Waters Xevo TQS-microTM) to quantify current use pesticides. The resultsshowed that levels of Glyphosate and Chlorpyrifos remained constant in these twosampling periods. AMPA and Imidacloprid were only found in summer. Both, the K andHIS indices were lower in summer than in spring. An increase of 581% in CAT activityfrom 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 weredetected between both seasons. These results show the role of antioxidant enzymes infish, since oxidative stress damage was not observed in terms of lipid peroxidation, maybe due to the increase of the antioxidant enzyme activities. The results found for theliver and gills are consistent, since liver is the main detoxifying organ and gills are theorgan with the highest exposure to agrochemicals1. In this way, biomarkers of oxidativestress in target organs are able to show the effects of some of the most used pesticidesin the region.