Effects of different sediment fractions on sorption of galaxolide

Sorption isotherms different fractions from two of galaxolide （HHCB） of sediments with different mineral and organic carbon contents were determined to compare HHCB sorption behavior and contribution to the total sorption. The HHCB sorption isotherms that used the batch equilibration method were studied on different sediments of different fractions. The sorption isotherms of 600℃ heating fractions were detailed using the linear model, while the other fractions were nonlinear and fitted well with the Freundlich carbon （DOC） removed, model. The dissolved organic NaOH extracted, and 375℃ heating fractions showed more nonlinear sorption than the original sediments, which suggested more heterogeneous sorption sites in these fractions. Compared to the original sediments, the 375~C heating fractions had higher carbon- normalized distribution coefficient （Koc） values, indicating a higher sorption affinity for HHCB. Among the different sediment fractions, the contribution of the 600℃ heating fractions to the overall sorption were the lowest （ 〈 20%）, while the 375℃ heating fractions were the highest （up to 85%）.

Distribution and elimination of polycyclic musks in three sewage treatment plants of Beijing, China

The two representative polycyclic musks, 1-（5,6,7,8-tetrahydro-3,5,5,6,8,8-hexamethyl-2-naphthenyl）-ethanone （AHTN） and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyrane （HHCB）, were measured in aqueous samples and sludge samples of three sewage treatment plants （STPs） in Beijing, China using a gas chromatograph-mass spectrometry. The HHCB and AHTN concentration ranges in the influents were 1251.4-3003.8 ng/L and 111.9-286.3 ng/L, respectively. Meanwhile, the ranges of 492.8-1285.3 ng/L for HHCB and 47.3-89.3 ng/L for AHTN were present in the effluents. The musks in the sludges were three to four orders of magnitude higher than those in aqueous sewages. The removal efficiencies.of the two musks varied in the ranges of 41.7%- 70.1% for HHCB, and 25.5%-68.8% for AHTN. Adsorption onto suspended particulate matter played an important role in removing musks from the sewages. The HHCB/AHTN ratio along the treatment processes showed that the two musks had high similarity of removal from sewage by each reactor in STP. The musks in the effluent sewages may pose a low potential risk to aquatic environment in terms of the predicted-non-effect concentration. Nevertheless, considering the possible additive and synergistic effects with other compounds emitted via STPs, their bioconcentration and bioaccumulation in aquatic organisms and so on, it is essential to monitor these compounds in various compartments and to study their environmental fate.

Occurrence and removal of selected polycyclic musks in two sewage treatment plants in Xi＇an, China

Polycyclic musks are widely used for cos- metics and other personal care and household cleaning products. The occurrence and removal of two representa- tive polycyclic musks, galaxolide （HHCB） and tonalide （AHTN） were investigated in three different processes of two sewage treatment plants （STPs） in Xi＇an, China. The samples were preconcentrated by solid phase extraction procedure and analyzed using a gas chromatography mass spectrometry （GC/MS） by a modified procedure. The HHCB was in the range of 82.8 to 182.5 ng.L1 in the influents and 22.6 to 103.9ng.L-1 in the effluents. The AHTN ranged from 11.0 to 19.3 ng. L-1 in the influents and 2.2 to 8.8 ng. I_~1 in the effluents. The removal efficiency of the two musks varied in the ranges of 43.1%-70.4% for HHCB and 54.2%-84.4% for AHTN. Concentrations of the two musks in aqueous phase of three processes slightly increased along the primary process, and significantly removed during the biologic treatment processes, revealing that the selected musks could be remarkably removed in varied activated sludge processes. Advanced processes of activated sludge did not show a significant superiority on selected musk removal compared to the conventional process. The selected musk removal mainly resulted from the adsorption function of activated sludge. There was no significant change of HHCB/AHTN ratios along the treatment flow, indicating that each sewage treatment structure had a similar removal efficiency for the two musks.