Dynamics of pesticides in the waters of the Descoberto region: Development of methods and analysis.
pesticides, water, Descoberto Basin, Federal District
The main source of water supply in the Federal District is the Descoberto reservoir, responsible for more than 50% of the supply. This reservoir is at risk of contamination by pesticides through surface runoff from fruit and vegetable crops in Brazlândia, a region that has shown significant growth in agricultural productivity in the Federal District. This project aims to validate analytical methods and collect samples for pesticide analysis at 46 points in the Descoberto Lake watershed, including tributaries of the lake, surface and groundwater intakes, and points in the distribution network. The study period extends from February 2026 to January 2027. Analytes were prioritized based on the main crops in the region and characteristics such as toxicity, mobility, and persistence. Analytical methods were developed and validated for these analytes, observing the presence of the pesticides acephate, carbendazim, atrazine and their degradation products during the rainy season and acephate, atrazine and their degradation products during the dry season. The pesticides acephate and carbendazim are possibly removed by water treatment, but atrazine is persistent. It was preliminarily considered that agricultural activity in Brazlândia impacts the runoff of pesticides into the water production system in the Descoberto region, considering the different types of intake evaluated, but does not represent a significant risk to human health.