Leaching of Pesticides from Fields with Recorded Pesticide Applications

During two winter seasons, 1998/99 and 1999/2000, drainage water was sampled each fortnight from four fields with recorded pesticide application. Water was analysed for a range of pesticides used on the fields. Two of the four fields were equipped with three vertical stainless steel tubes with screens at 1-1.3 m depths. Two other fields were equipped with traditional tile drains, which solely drained the specific fields. Isoproturon, which was banned from use after 1999, was the most frequently found pesticide in the drainage water. Pendimethalin was another compound frequently found, however in low concentrations. In drainage water from a field at Silstrup the active ingredients bentazone and propyzamide appeared in the drainage water at the first sampling following treatment and during the following months. The highest concentration levels were 1.3 and 2.8 µg/L, respectively. Phenoxyacid herbicides, which had been detected at concentration levels up to 0.34 µg/L in an earlier study 10 years ago, no longer appeared in the drainage water.

Keywords:

• Pesticides
• Leaching
• Drainage Water
• Liquid Chromatography Mass Spectrometry