Abstract
The occurrence of sixteen synthetic fragrance materials and nine organic UV filters was investigated in influent, effluent, and excess sludge in 47 sewage treatment plants (STPs) in Japan. Their loads into the STPs and into an aquatic environment via STPs were estimated according to their influent and effluent concentrations. Highest loads in influent into the STPs and effluent into the aquatic environment were 1.79 mg · day-1 · inch-1 for homosalate and 0.31 mg · day-1 · inch-1 for ethylhexyl methoxy cinnamate (EHMC), respectively. Removal ratios of the fragrance materials and organic UV filters in the STPs were also calculated. The removal ratios varied markedly among compounds. The minimums of the removal ratios were higher than 90 % for benzyl acetate, methyl dihydrojasmonate, octyl salicylate, homosalate, benzyl salicylate, isoamyl-p-methoxycinnamate, and octocrylene, moreover, the lowest removal ratio was approximately 50 % for EHMC. The removal ratios due to adsorption onto the sludge to the total removal ratio were evaluated from the concentrations of compounds in the return sludge. The highest ratio of the removal due to adsorption onto the sludge to the total removal ratio was 40 % for 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclo-penta-[g]-2-benzo-pyrane and 7-acetyl-1,1,3,4,4,6-hexamethyl tetrahydro-naphthalene. Many of the organic UV filters measured were evaluated to be less removed by adsorption because of the markedly higher adsorption to the influent sludge than to the return sludge. Further research on their adsorption and biodegradation in the STPs is required.
