Monitoring of Atrazine Pollution and its Spatial-Seasonal Variation on Surface Water Sources of an Agricultural River Basin.

Surface water sources are greatly impacted in areas with major agricultural land use. The atrazine quantification in surface waters as well as the spatial-temporal patterns of this herbicide was studied to detect pollution hotspots and to understand the putative factors responsible of its occurrence at the Ctalamochita river basin. The samples were collected on the aeolian fluvial plain of the river basin during five consecutive years. The results showed the high ubiquity of this compound and several sites with hazardous concentration (exceeding 0.1 µg/L international guidelines). The frequencies of quantification range from 67 to 100% in spring and 33%-67% in autumn. The atrazine content in surface water increased during the warm-rainy season, as consequence of atrazine application events (coinciding to the prevalent crop type). Overall, the study highlights the factors that could have favored atrazine pollution in the river basin such as land use, transport by runoff processes and atmospheric deposition.