Status of organochlorine (DDT) pollutants and steps toward electrocatalytic reductions

The accumulation of DDT in the environment over the years is a major concern in the world today. The extent to which DDT may be absorbed and translocated from C-14-p,p'-DDT contaminated soils into cowpea plant tissues, and the variation of uptake of p,p'-DDT by the plants in relation to the dissipation of p,p'-DDT in the soils was studied using a radioisotope technique. Significant absorption and accumulation of residues was observed for the cowpeas grown in two different sites, coastal and highland regions. The degree of uptake varied with soil type and growing conditions. Further results indicated that the higher the water retention by the soil the higher the rate of evaporation of p,p'-DDT. Coastal region p,p'-DDT soil samples showed DDE to be the major metabolite. DDT residue in the plants ranged from 0.94 to 7.73 mg/kg, while that in the soils ranged from 88.9 to 32.0 mg/kg. Preliminary electrode reactions indicated lowering of overpotential for reduction of p-chlorophenol by about 1 V, using copper phthalocyanine tetrasodium tetrasulfonate as the catalyst in microemulsion. Microemulsions and appropriate catalysts are a promising system for the decomposition of DDT.