| Various studies have demonstrated the presence at high levels of pesticides and nitrate in soil, surface, and groundwater. Prior studies have identified a watershed area in Brazil with a high risk of soil, surface, and groundwater contamination by pesticides at the region of Riberao Preto, SP. Surface and groundwater were collected at the area during the period of October 1995 to November 1998. By means of gas chromatography-mass spectrometry (GC-MS) technique the herbicides tebuthiuron, diuron, simazine, atrazine, and ametryne, and nitrate were analyzed according to the protocols established in literature. The recovery obtained in the extraction procedure was higher than 95% for all herbicides except simazine for which the recovery was 85,6%. Due to the... |
