ALTERATION OF PESTICIDE CONTENT IN THE SOIL SOLUTION COLLECTED BY A POROUS CUP

Investigations were conducted to test the suitability of porous cups f or sampling soil water to determine pesticides. Pesticide contents wer e controlled over a sampling period in an aqueous medium containing so luble organic matter and in a soil medium treated with atrazine or iso proturon both C-14-labelled. The tests proved that the disturbance of pesticide concentration in the extracted water concerned only the firs t volume extracted (fifty milliliters). Thus, the resulting 500 ml sam ple had a herbicide content close to that of the corresponding leachat e. The system still worked well after a dessication period or a simula ted rainfall. These results confirmed clearly the usefulness of porous cups for pesticide monitoring campaigns provided the samples volume i s superior to 50 ml.