Occurrence and distribution of phthalate esters (PAEs) in wetland sediments

Abstract

This study investigated the occurrence and distribution of 15 phthalate esters (PAEs) in sediments collected from Qixinghe wetlands, northeast China. Total concentration of PAEs in all sediments ranged from 128.41 to 502.79 μg kg−1, with the mean value of 284.61 μg kg−1. PAEs significantly differed among wetland types; the average PAEs concentration of surface sediments were as follows: Phragmites australis wetland (PAW, 419.87 ± 73.61 μg kg−1) > Carex lasiocarpa wetland (CLW, 304.18 ± 56.47 μg kg−1) > Deyeuxia angustifolia wetland (DAW, 129.78 ± 18.24 μg kg−1). Dimethyl phthalate (DMP), diisobutyl phthalate, di-n-butyl phthalate, and di-(2-ethylhexyl) phthalate (DEHP) were found in all sediments, DEHP was the most abundant PAEs congeners with concentrations varying from 37.62 to 294.9 μg kg−1. DMP and DEHP exhibited relatively higher concentrations in CLW and PAW wetlands than in DAW, indicating that the different deoxidization and biodegradation conditions could have important implications for the distribution patterns of PAEs in wetland sediments. The variation of PAEs concentrations in horizontal and vertical sediments with wetland types could be attributed to the migration of contaminants by surface water, groundwater and atmospheric deposition. The occurrence and distribution of PAEs in wetlands also suggests that contamination in natural ecosystems should not be overlooked.