This is the first report about the presence of pesticide residues in water and sediments from Chacahua-Pastoria Lagoon System in the Oaxaca Coast, Mexico. Organochlorine and organophosphate pesticides were analyzed in water and sediment samples collected during rainy and dry seasons in 2018. The pesticides extraction was carried out by 525.2 EPA and QuEChERS methods for water and sediments samples, respectively. The quantification was done by gas chromatography coupled to electron microcapture (μECD) and flame photometric (FPD) detectors. Univariate and multivariate analysis were carried out to evaluate the distribution patterns, comparing between lagoons, seasons and matrices. The spatial distribution of malathion and organochlorines in water showed the highest values near to adjacent land with some patterns differences. DDT was the most frequent in water and sediments samples, showed the highest concentrations in the Pastoria Lagoon. These results indicate the need to establish a permanent monitoring programs to implement mitigation measures.

这是关于墨西哥瓦哈卡海岸查卡瓦-帕斯托里亚泻湖系统的水和沉积物中存在农药残留的第一份报告。对 2018 年雨季和旱季采集的水样和沉积物样品中的有机氯和有机磷农药进行了分析。农药提取分别采用 525.2 EPA 和 QuEChERS 方法对水和沉积物样品进行。通过与电子微捕获 (μECD) 和火焰光度 (FPD) 检测器耦合的气相色谱法进行量化。进行单变量和多变量分析以评估分布模式，比较泻湖、季节和矩阵。水体中马拉硫磷和有机氯的空间分布在邻近土地附近表现出最高值，但存在一定的格局差异。DDT 是水和沉积物样品中最常见的，在 Pastoria 泻湖中浓度最高。这些结果表明需要建立一个永久性的监测计划来实施缓解措施。