Negro Carlos Leandro, Viozzi María Florencia, Iturburu Fernando Gastón, Mora María Celeste, Reyes Paula Sofía, Repetti María Rosa, Williner Verónica
Instituto Nacional de Limnología (CONICET-UNL), Ciudad Universitaria, Paraje El Pozo s/n, 3000, Santa Fe, Argentina; Escuela Superior de Sanidad, Facultad de Bioquímica y Ciencias Biológicas (UNL), Ciudad Universitaria, Paraje El Pozo s/n, 3000, Santa Fe, Argentina.
Instituto Nacional de Limnología (CONICET-UNL), Ciudad Universitaria, Paraje El Pozo s/n, 3000, Santa Fe, Argentina.
Environ Pollut. 2025 Sep 15;381:126584. doi: 10.1016/j.envpol.2025.126584. Epub 2025 Jun 3.
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. As streams converge into larger rivers, their water quality may undergo significant changes, particularly in terms of pesticide concentrations. Ten different sites along lowland stream were studied, from the headwaters to the mouth near the Middle Paraná river. Five physicochemical parameters and pesticide concentrations (135 compounds including glyphosate and its metabolite AMPA) in the water were measured. Additionally, Macrobrachium borellii shrimp were exposed for 7 day at each site in a field cage design. After exposure, five enzymatic and non-enzymatic parameters related to oxidative stress were measured in the hepatopancreas and seven in the muscle. At 2 first-order streams and 1 s-order stream the environmental conditions were sufficiently stressful to induce 100 % mortality in exposed individuals. Among surviving shrimp, oxidative stress biomarkers were predominantly elevated in headwaters and 1 s order stream. Significant positive correlations were detected between specific pesticide concentrations and certain biomarkers. Multivariate GLM analysis revealed that atrazine concentrations significantly explained variations in catalase and superoxide dismutase activities in muscle tissue. However, the most pronounced shifts in oxidative stress parameters occurred at sites where physicochemical variables (e.g., dissolved oxygen, pH) were stronger predictors than pesticide levels, with no clear dose-response relationship observed for pesticides alone. These findings underscore that first and second order streams related with headwaters represent the most ecologically stressful aquatic environments in the studied system, warranting targeted conservation efforts and further research to elucidate underlying mechanisms.
潘帕斯地区的特点是地势平坦，坡度平缓，农业用地广泛。与农业集水区相关的溪流和河流通常受到用于农作物的农药影响，这些农药会漂移到水生环境中。随着溪流汇聚成更大的河流，其水质可能会发生显著变化，特别是在农药浓度方面。对低地溪流沿线从源头到巴拉那河中游附近河口的10个不同地点进行了研究。测量了水中的五个理化参数和农药浓度（包括草甘膦及其代谢物AMPA在内的135种化合物）。此外，采用野外网箱设计，在每个地点将博氏沼虾暴露7天。暴露后，在肝胰腺中测量了与氧化应激相关的五个酶促和非酶促参数，在肌肉中测量了七个。在2条一级溪流和1条二级溪流中，环境条件压力足够大，导致暴露个体100%死亡。在存活的虾中，氧化应激生物标志物在源头和二级溪流中主要升高。在特定农药浓度与某些生物标志物之间检测到显著的正相关。多变量广义线性模型分析表明，阿特拉津浓度显著解释了肌肉组织中过氧化氢酶和超氧化物歧化酶活性的变化。然而，氧化应激参数最明显的变化发生在理化变量（如溶解氧、pH值）比农药水平更能预测的地点，单独的农药未观察到明确的剂量反应关系。这些发现强调，与源头相关的一级和二级溪流代表了研究系统中生态压力最大的水生环境，需要有针对性的保护措施和进一步研究以阐明潜在机制。
