| Synthetic musks are widely used in personal care products as fragrances and they enter sewage treatment plants (STPs) through the municipal sewage system. Aqueous sewage (i.e. influent, primary effluent and final effluent) and sludge/biosolids (i.e. combined raw sludge, return activated sludge and digested biosolids) samples from the Peterborough STP, Ontario, were analyzed for 11 synthetic musk compounds using gas chromatography/mass spectrometry with selected ion storage (GC/MS-SIS). The results showed that 1,3,4,6,7,8-h&barbelow;exahydro-4,6,6,7,8,8-h&barbelow;examethylc&barbelow;yclopenta[g]-2-b&barbelow;enzopyrane (HHCB, 173.1 +/- 43.4 ng/L) and 7-a&barbelow;cetyl-1,1,3,4,4,6-h&barbelow;examethyl-t&barbelow;etrahydron&barbelow;aphthalene (AHTN, 41.6 +/- 15.8 ng/L) are the dominant fragrances in Peterborough sewage effluent, but other polycyclic musks and nitro musks are present at low concentrations. The overall removal rate of synthetic musks in the STP ranged from 43.3 to 56.9%. However, removal occurred mainly by partitioning into sludge/biosolids. The concentrations of HHCB and AHTN in aqueous phase were highly correlated with both BOD5 and TOC. The concentrations of synthetic musk in sludge/biosolids (dry mass) were usually at least three to four orders of magnitude greater than that in sewage due to their hydrophobicity. Based on a mass balance model, the daily input and output of HHCB and AHTN in this STP were 47 g and 46 g, respectively. |
