Degradation dynamics and residues of clopyralid in surface and groundwater on fields of lower silesia.

摘要

The aim of investigations was to evaluate the influence of weather conditions and kind of water on clopyralid decomposition and herbicidal pollution in surface and groundwater on arable areas. The degradation of clopyralid was studied in laboratory experiments in three containers with water (water from well and distillated water). Water samples were collected 1, 2, 5, 9, 12, 16, 24, 30, 44, 63, 82 and 103 days after herbicide application. The monitoring were conducted in years 2001-2004. The samples were collected (from stationary points located in the South-West Poland) twice a year (in spring and autumn approximately 4-6 weeks after nominal term of herbicide application). Surface water was collected from 35 points and groundwater from 24 wells. The analyses of clopyralid residues were conducted using gas chromatography (GLC) with ECD detection. The weather conditions and kind of water influenced clopyralid half-life (12-24 days). Darkness and low temperature significantly reduced the degradation rate. The residues of clopyralid in surface and groundwater (in spring and autumn) were detected. The residues of active compounds in surface and groundwater were detected most frequently in springtime. The maximum residues detected in surface water samples did not exceed 0.00006 mg/ha. In groundwater (from wells), residues were detected sporadically and its level did not exceed 0.00002 mg/ha. Residues at concentrations exceeding the EU and Polish safety standards (0.0001 mg/ha) were not detected..