Occurrence, spatial distribution, historical trend and ecological risk of phthalate esters in the Jiulong River, Southeast China

The occurrence and spatial distribution of phthalate esters (PAEs) in the Jiulong River of southeast China were investigated in water and sediment samples collected from 35 stations along the river in Mar. 2014. The historical trend of the past 26 years was reconstructed with a sediment core collected in Dec. 2012 via a 210Pb dating technique. The potential ecological risk of PAEs was assessed using the risk quotient (RQ) method. Of the 16 PAE congeners analyzed, only 6 PAEs, including dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP), were identified and quantified; the remaining 10 PAEs were below their respective limits of quantification (LOQs) for the analytical methods used here. The cumulative concentration of 6 PAEs (∑6PAEs) found in the samples spanned a range of 3.48–17.7 μg/L in water and 0.046–1.65 mg/kg in sediment. The most abundant PAEs in the water-phase were DEHP and DIBP, together accounting for 84.9% of ∑6PAEs in the North River, 82.8% of ∑6PAEs in the West River and 91.6% of ∑6PAEs in the estuary. DEHP and DINP were the richest congeners in the sediment-phase, with proportions of 84.9% in the North River, 81.0% in the West River and 65.4% in the estuary. The spatial distribution of ∑6PAEs in water and sediment phases showed that the riverside environment had influence on the distribution pattern. The reconstruction profile of the PAE congeners and the ∑6PAEs vs the depth of the sediment core indicated that PAEs became increasingly present pollutants around 2006 in the Jiulong River. The results of the potential ecological risk assessment of the RQ method revealed that DIBP and DEHP posed a high risk because of their relatively higher concentrations, while DBP and DINP posed a medium risk to the aquatic system. The baseline data of PAEs in this river will be benefits to the regulatory attention and future strategies of the pollutants control along the river network.