Dissipation of 14c‐p,p'‐DDT in two Panamanian soils
Abstract Dissipation of 14C‐p,p'‐DDT in two Panamanian soils was studied up to two years under field conditions. The highland soil from Cerro Punta had an organic matter content of 7.1% and pH 6.1, while the lowland soil from El Coco had an organic matter content of 1.9% and pH 5.5. The time required for the initial dissipation of 50% of 14C was 135 and 365 days for Cerro Punta and El Coco soils respectively. After 2 years, extractable 14C was 16% and 28% for Cerro Punto and El Coco soils respectively. As the climatic conditions were the same, these differences in dissipation rates must relate to the soil properties. While the organic content and microbiological complexes may differ, it is also likely that the soil pH can play a role, where the higher acidity may retain the insecticide and its products for longer periods. Binding to soil amounted to approximately 9% after 2 years in both soils. It is concluded that p,p'‐DDT dissipates from Panamanian tropical soils at rates higher than those reported for ...