Abstract:
In order to explore the multi-phase partitioning and eco-risk of EDCs in water, colloids, and suspended particulate materials (SPM) in the Zhujiang River and the Dongjiang River, Pearl River Delta, the cross-flow ultrafiltration, solid phase extraction, and gas chromatography-mass spectrometry were employed. The typical EDCs 4-tert-octylphenol (OP), 4-nonylphenol (NP), bisphenol A (BPA), estrone (E1), diethylstilbestrol (DES), 17β-estradiol (E2), estriol (E3) and 17α-ethynylestradiol (EE2) were selected as the target compounds. It was observed that about 60% of OP, NP, and BPA were soluble in water phase, 30% were bound with colloids, and 10% were associated with SPM. DES, E2, EE2, E3 were not detected in these tested samples. Moreover, NP and BPA concentrations were both positively correlated with the dissolved and particulate organic carbon (OC) contents, respectively. The dissolved OC-normalized concentrations of OP, NP, BPA, E1, respectively, were positively correlated with the specific UV absorbance at 254 nm (SUVA254) in the dissolved phase, suggesting that they can be bonded with dissolved organic matters through π-π interaction which was related with the aromaticity. Moreover, the in situ particle-water and colloid-water partition coefficients (Koc and Kcoc) were calculated. The log Koc values for OP, NP and BPA were 4.41±0.69, 4.60±0.32 and 4.30±0.43, respectively, and their log Kcoc values were 5.35±0.42, 5.69±0.50 and 5.51±0.77, respectively. The Kcoc were one order of magnitude higher than the Koc, indicating the more powerful affinity of colloids with the EDCs than that of SPM. In addition, the environmental risk quotient (RQ) approach was used to briefly assess the potential risk of the two rivers. The RQ values were in a range of 0.39~2.01, indicating that the Zhujiang River likely have the high risk with a mean value of 1.5, and the Dongjiang River contain the medium risk with an average value of 0.75. It was also found that the risk in the bottom water layer were higher than that in the surface layer.
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