RADIOLYTIC TREATMENT OF DIOXIN CONTAMINATED SOILS

Recent work in our laboratory has demonstrated that gamma-radiolysis i s a feasible method by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD ) can be converted to products of negligible toxicity. In the presence of 25% water, 2.5% non-ionic surfactant and at a dose of 800 kGy grea ter than 98% destruction was achieved in a standard soil artificially contaminated with 100 ppb TCDD. By-product analysis has illustrated th at the destruction occurs via step-wise reductive dechlorination produ cing a suite of lesser chlorinated dioxins. These results in combinati on with scavenger studies, target theory calculations and yields indic ate that direct radiation effects account for the major route of destr uction. Radiolysis has also been conducted on a real soil contaminated with TCDD and other chlorinated aromatic compounds verifying the resu lts of model studies. Based on the data of these experiments some desi gns of batch gamma systems are considered and a discussion of estimate d capital and operating costs associated with gamma-radiolysis is pres ented. Given the high costs of the alternatives (i.e. incineration), r adiolysis appears to be not only technically feasible, but it may also be economically competitive.