Occurrence of emerging and priority pollutants in municipal reverse osmosis concentrates
This paper aimed to investigate the occurrence and concentrations of emerging and priority pollutants in the municipal reverse osmosis concentrate (ROC) using liquid–liquid extraction (LLE) followed by gas chromatography-mass spectrometry. The results indicated that there were varieties of pollutants, including chlorinated organic compounds, polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs), pharmaceutical and personal care products (PPCPs), herbicides and flame retardants, in the ROC. Most of the pollutants were quantified, and the performance of the analytical method was explored. For most of the target compounds, the mean recoveries at two concentration levels (0.17 μg L−1 and 1.67 μg L−1) ranged from 70% to 130% and the relative standard deviation (RSD) values were less than 20%, indicating excellent accuracy and precision. Typical concentrations of most of the pollutants were as low as tens or hundreds of ng L−1, whereas others were as high as several μg L−1 (such as, the concentration of 2-chloroethyl ether was 1.42 μg L−1, of caffeine was 3.73 μg L−1, and of benzyl butyl phthalate was 4.90 μg L−1).