OCCURRENCE, SPATIAL DISTRIBUTION AND ECOLOGICAL RISK ASSESSMENT OF PHTHALATE EASTER PLASTICIZERS IN SEDIMENTS OF MOBILE BAY, UNITED STATES

Phthalate esters (PAEs) are an important additive in many plastics and have a broad range of industrial and domestic applications. Their accumulation in the coastal environment has a toxic impact on marine organisms that can be passed on to human beings. Here, we reported the first set of PAE data in the sediments of Mobile Bay, a large ecologically and economically important estuary. We investigated the pollution characteristics, spatial variation, and potential ecological risk of PAEs. Ten PAE compounds were detected. Dimethyl phthalate (DMP) and di-butyl phthalate (DBP) were predominant, accounting for >50% of total PAE concentrations. The preliminary data show that total PAE concentrations varied from 0.08 µg/g to 1.55 µg/g (average = 0.51±0.42 µg/g). PAE concentrations did not differ significantly between the western and eastern estuary (Mann-Whitney U test P=0.343), suggesting that the wastewater and sewage discharges more concentrated in the west were likely not the source for PAEs. However, the total PAE concentrations exhibited a significant negative correlation with salinity (Spearman’s ρ=−0.733, P=0.007), indicating that riverine runoff acted as an important pathway transporting PAEs from the Mobile River catchments to the estuary. None of the samples analyzed so far showed DMP or DBP concentrations above the environmental risk limits, and the risk quotient values of DMP and DBP were all <1. These preliminary results suggest an insignificant environmental risk of PAEs posed to algae, crustaceans, and fish. Our study provides the first dataset of plasticizer compounds in Mobile Bay, and the associated information will benefit environmental management practices.