ENVIRONMENTAL FATE, BEHAVIOR AND ECOTOXICITY OF CHLORPYRIFOS IN SOILS FROM NORTH PATAGONIAN REGION

AGUIAR MARÍA B.; MELIDEO CARLOS F.; LATINI LORENA A.; LOEWY RUTH M; SAVINI MÓNICA C; INDACO MARÍA M.; PAROLO MARÍA E; MONZA LILIANA B.

FOZ DO IGUAZU

Workshop; 7TH LATIN AMERICAN PESTICIDE RESIDUE WORKSHOP; 2019

UNIVERSIDAD FEDERAL DE SANTA MARIA

The intensive use of pesticides during the past decades has highlighted thepotential risk to humans and the environment, including soil biota. The presenceof pesticide residues in soil, sediment and water samples has raised public andscientific concern. Among the factors that affect the environmental distributionof pesticides are agricultural practices during and after pesticide application,climate change, new technologies used in pesticide formulation and newapplication-release strategies[l]. The study of the pesticides soil distribution andits affinity with the different soil components enable us to evaluate its ability toreach and contaminate groundwater. For this purpose, the sorptive propertiesof twelve soils, with different organic matter (OM) content (2-11 %) and pH (5.5-8.2), were analyzed determining the chlorpyrifos (CPF)adsorption coefficients(KD) in equilibrium conditions experiments. At the same time, pesticide leachingwas determined on a selected agricultural soil by field Iysimeters under realpesticide application and laboratory studies were carried out in undisturbed soilcolumns. Leaching and equilibrium solutions were extracted by LLE(Liquid-liquidextraction) and analyzed by GCINPD. KD values obtained (140-1100 L kg-1) werecorrelated with the OM content, suggesting that CPFdistributes between aqueousand solid phase as a function of the hydrophobic interactions with the soil organicmatter. The laboratory undisturbed columns results show that CPF is strongerretained in the first 5 cm of soil column and 0.31 % of CPFapplied was recoveredas leaching, which is in agreement with the value obtained at field Iysimetersexperiments. Ecotoxicological tests are useful tools to assessthe extent to whicha chemical are harmful and how and where their effects occur. In this work, theAvoidance Behavioral Test using the earthworm Eisenia foetida was performedaccording to ISO 17512-1. The soil tested was the same soil used in the columnsand the Iysim,.eters,which it was fortified at 0.48 mg/kg of CPF.The assay lasted48 h (25°C+-::20C, under light!dark cycle of 12: 12 h). No earthworm mortalitywas observed and the mean net response was 60%. This integrated approachincluding batch experiments, laboratory sorption columns, field Iysimeters andecotoxicological tests for a selected soil would allow us to infer the environmentalbehavior of CPF on different soils. This is essential to define strategies for asustainable development of groundwater resources.