Environmental Behaviors Of Phthalic Acid Esters In Haihe Estuary

Based on the pollution condition of nutrients and phthalic acid esters (PAEs), the fate of dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP), listed as priority pollutants by US EPA and suspected to be environmental hormone, in Haihe estuary was carried out. Three approaches were used: monitoring in the field environment, simulating laboratory experiments and mathematics model.The results of field investigation showed that pollution of nutrients and phthalic acid esters was serious. Concentrations of DEHP in water samples were a little higher than those of DBP, and concentrations of DEHP in sediment samples were obviously higher than those of DBP. Partition coefficient of DEHP between water and sediment was higher than that of DBP.Effects of nutrients and light on DBP and DEHP biodegradation in water samples of Haihe estuary were investigated. The results showed that biodegradation of DBP and DEHP in the water samples followed first-order kinetics, and the transformation is primarily biotic. First-order biodegradation rate constant of DBP and DEHP was higher under high nutrient condition than low nutrient condition. Biodegradation of DBP and DEHP was retarded in the presence of illumination. Under the same condition, DBP was easy to be biodegraded by compared with DEHP.The experimental results in a microcosm showed that biodegradation of DBP and DEHP in water samples followed first-order kinetics. Biodegradation rate constants of DBP and DEHP were higher under high nutrient condition than low nutrient condition. Biodegradation rate of DBP in the water sample was higher than that of DEHP. Accumulation of DEHP in sediment was higher than that of DBP.Levelâ…£multimedia fugacity model was applied to the microcosm. The results showed that biodegradation of DBP in water phase and sediment phase was the most improtant processes. DBP concentrations in sediment were influenced by the fagucity difference of DBP between water and sediment and biodegradation of DBP in sediment. The sediment, which accounts for small part of the system by mass, played an important role in removal of DBP. 90% of DBP, transferred from water phase to sediment phase, was by suspended particle deposition.