EVALUATION OF A SAMPLING METHOD FOR THE ANALYSIS OF CHLOROPHENOXY HERBICIDES, N-CONTAINING PESTICIDES AND PAHS IN RAIN WATER

The influence of a sampling method for rain water on the quality of th e analytical results obtained for pesticides and polycyclic aromatic h ydrocarbons (PAHs) was studied. Also the possibility of applying a sin gle sampling method for the analysis of a selected group of chlorophen oxy herbicides, nitrogen containing pesticides and PAHs was evaluated. A conservation experiment was performed using 8 bottles of rain water with known amounts of the components which were sampled at regular ti me intervals (0, 4, 6 and 8 weeks). The influence of 6 discrete parame ters was investigated by varying these parameters using a two level fa ctorial experimental design. The selected parameters were the amounts of the three analysed groups of compounds, the addition of copper sulp hate (to eliminate algal growth), the type of rain gauge and the use o f open or closed conservation bottles. The samples from the conservati on bottles were analysed both on the amount of pesticides and PAHs. Us ing the present sampling technique the addition of copper sulphate app eared to have a negative influence on the stability of cyanazine and a positive effect on the stability of the chlorophenoxy herbicides. Oth er parameters which had systematic effects were the fact whether open or closed container bottles were used and the type of rain gauge.