Datos Ambientales y Enzimáticos - Camarones - Del Chupino: Monje

Abstract

The Pampean region is characterized by a flat land area with gentle slopes and extensive agricultural land use. Streams and rivers associated with agricultural catchments are usually affected by pesticides that are used on crops and drift into aquatic environments. These streams may exhibit different characteristics, as they flow into larger rivers, particularly regarding pesticide concentrations. Ten different sites along lowland stream were studied, from the headwaters to the mouth near the Middle Paraná River. Physicochemical parameters and pesticide concentrations in the water were measured. Additionally, Macrobrachium borellii shrimp were exposed for seven days at each site in a field cage design. After exposure, enzymatic and non-enzymatic parameters related to oxidative stress were measured in the hepatopancreas and the muscle. A control group was caged and maintained in containers used during the acclimation period. At several headwater sites, environmental conditions, including pesticide concentrations, were sufficiently stressful to cause 100% mortality for individuals. Among surviving shrimp, oxidative stress was mainly observed in the headwaters (first-order streams). Overall, positive correlations were observed between the pesticide concentrations and biomarkers, although some biomarkers showed negatively correlations. According to MANOVA, atrazine concentrations better explained Catalase and Superoxide Dismutase activities in the muscle. The integrative biomarker response showed a general increase in biomarker responses, with a 1st order stream being the most stressful site. The headwaters were the most affected and stressful aquatic environments and should be those where more conservation efforts should be made.