Transformation products and reaction kinetics of fragrances in advanced wastewater treatment with ozone

The reaction of the fragrance compounds 4,6,6,7,8,8-hexamethyl-1,3,4,7-tetrahydrocyclopenta[g]isochromene (HHCB), 1-(3,5,5,6,8,8-hexamethyl-6,7-dihydronaphthalen-2-yl)ethanone (AHTN), 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene (musk xylene/MX), 1-(4-tert-butyl-2,6-dimethyl-3,5-dinitrophenyl)ethanone (musk ketone/MK), and 1-(2,3,8,8-tetramethyl-1,3,4,5,6,7-hexahydronaphthalen-2-yl)ethanone (OTNE) with ozone in tap water as well as waste water treatment plant (WWTP) effluents is described. Several transformation products are characterized by means of gas chromatography coupled to mass spectrometry. One transformation product (HHCB-Lactone) was confirmed by means of a true standard. Musk xylene and musk ketone do not react with ozone under the conditions used in this study. AHTN and HHCB reacted slowly to a multitude of transformation products, while OTNE reacted quickly to several stable transformation products. The reaction constants and half lives are used to predict removal efficiencies for full scale reactors.     

Concentrations and assessment of exposure to siloxanes and synthetic musks in personal care products from China

We investigated the concentrations and profiles of 15 siloxanes (four cyclic siloxanes, D₄-D₇; 11 linear siloxanes, L₄-L₁₄), four synthetic musks (two polycyclic musks, HHCB and AHTN; two nitro musks, MX and MK), and HHCB-lactone, in 158 personal care products marketed in China. Siloxanes were detected in 88% of the samples analyzed, at concentrations as high as 52.6 mg g⁻¹; Linear siloxanes were the predominant compounds. Among synthetic musks, more than 80% of the samples contained at least one of these compounds, and their total concentrations were as high as 1.02 mg g⁻¹. HHCB was the predominant musk in all of the samples analyzed, on average, accounting for 52% of the total musk concentrations. Based on the median concentrations of siloxanes and musks and the average daily usage amounts of consumer products, dermal exposure rates in adults were calculated to be 3.69 and 3.38 mg d⁻¹ for siloxanes and musks, respectively.     

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

Polycyclic musks are widely used for cosmetics and other personal care and household cleaning products. The occurrence and removal of two representative 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·L^-1 in the influents and 22.6 to 103.9 ng·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·L^-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.     

Occurrence and accumulation patterns of polycyclic aromatic hydrocarbons and synthetic musk compounds in adipose tissues of Korean females

Very few studies have reported on the occurrence and accumulation profiles of polycyclic aromatic hydrocarbons (PAHs) and synthetic musk compounds (SMCs) in human adipose tissue. In this study, concentrations of PAHs and SMCs in adipose tissues collected from Korean women in 2007 and 2008 were determined. Total concentrations of PAHs and SMCs in adipose tissues ranged from 15 to 361 (mean: 119) ng g^-1 lipid weight and from 38 to 253 (mean: 106) ng g^-1 lipid weight, respectively. Concentrations of SMCs in Korean adipose tissues were lower than those reported for European countries and the United States. Naphthalene was the most predominant PAH and HHCB was the dominant SMC found in adipose tissues. The concentrations of PAHs and SMCs were not correlated with each other, suggesting that the sources of human exposure to these two classes of compounds are different. No correlation was found between donor’s age and residue levels of PAHs and SMCs. The results of this study provide baseline information on exposure of PAHs and SMCs to the general population in Korea.