LEACHING OF TERBUTHYLAZINE AND ATRAZINE THROUGH LABORATORY SOIL COLUMNS

The leaching of terbuthylazine and atrazine was studied through labora tory soil columns using little to moderately carbonated soils and with fine texture. Mobility in the three soils was greater for atrazine th an terbuthylazine. This might be related to the higher water solubilit y of atrazine, 30 mg L-1 versus 8.5 mg L-1 for terbuthylazine, and to the smaller Freundlich adsorbtion coefficient of atrazine, from 0.96 t o 1.22 depending on the soil, compared with 1.88 to 2.33 for terbuthyl azine. No significant difference in mobility was observed between the three soils.