Stereoselective uptake and degradation of (±)-o,p-DDD pesticide stereomers in water-sediment system.

The environmental stereoselective uptake and degradation of (±)-o,p-DDD pesticide stereomers in water-sediment system are described. The results were analyzed by artificial neural network model. The optimized experimental parameters were concentration of o,p-DDD streamers (7.0 μg L-1 ), experimental time (60 min), pH (6), dose (5.0 g L-1 ), and temperature (25°C). The maximum uptake and degradation were 87% and 85% and 33.0% and 30.5% for (-)- and (+)-stereomers of o,p-DDD in 15-day time. Both uptake and degraded phenomenon showed first-order rate reaction. Thermodynamic variables indicated exothermic nature of uptake and degradation processes. The uptake and degradation were slightly higher for (-)-stereomer than (+)-stereomer of o,p-DDD. It was assumed that both uptake and degradation processes are accountable for the removal of the streomers of o,p-DDD from earth's ecosystem, but the uptake is responsible for major contribution. The magnitudes of relative errors obtained by artificial neural network model were in the range of ±0.2 to 3.5, indicating good applicability of the experimental data. The results are very useful to control the environmental contamination due to the chiral o,p-DDD pesticide as its two enantiomers have different ecological toxicities.