Integrated ecotoxicological assessment of the complex interactions between chlorpyrifos and glyphosate on a non-target species Cnesterodon decemmaculatus (Jenyns, 1842).

BONIFACIO, ALEJO FABIAN; ZAMBRANO, MICAELA JIMENA; HUED, ANDREA CECILIA

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2020

0045-6535

Pesticide mixtures are frequent in freshwaters systems around the world, threatening the biota exposedto these conditions. The aim of this study was to determine the single and joint effect of two widely usedpesticides in southern South America on a widely distributed fish species. In a 96-h assay, individuals ofCnesterodon decemmaculatus were exposed to 0.84 nL/L and 8.4 nL/L of Clorfox and 0.2 mg/L and 2 mg/Lof Roundup Max, commercial formulations of chlorpyrifos and glyphosate, respectively. Also, there werefour mixture treatments with all the possible combinations of both pesticides. A multi-level approachwas carried out to assess their effects covering the following relevant biomarkers: behavior (immobiletime, line crossings and average speed), somatic conditions (Fulton condition factor and hepatosomaticindex), serum parameters (cortisol levels, lactate dehydrogenase (LDH), and creatine phosphokinaseactivity (CPK)), brain and muscle acetylcholinesterase and cytological characteristics (micronuclei frequencyand nuclear abnormalities in erythrocytes). Our results showed that Clorfox exposures affectbehavioral parameters, serum cortisol, and nuclear characteristics of erythrocytes. Roundup Max affectsonly the cortisol levels whereas mixture treatments have an effect on behavioral parameters, cortisollevels, LDH and CPK activities, and nuclear characteristics of erythrocytes. Potentiation was the maininteraction at the lowest concentrations of both pesticides whereas antagonism occurred at the highestconcentrations of both pesticides. These results are highly significant since they arise from an integratedecotoxicological assessment at several levels of biological organization but even more important is thatthe potentiated effects of the mixtures we registered are environmentally relevant concentrations.