Distributions of polycyclic musk fragrance in wastewater treatment plant (WWTP) effluents and sludges in the United States.

The polycyclic musks, AHTN and HHCB are fragrance ingredients widely used in consumer products. A monitoring campaign was conducted and collected grab effluent and sludge samples at 40 wastewater treatment plants (WWTP) across the United States to understand their occurrence and statistical distribution in these matrices. AHTN concentration in effluent ranged from <0.05 μg/L (LOQ) to 0.44 μg/L with a mean and standard deviation of 0.18 ± 0.11 μg/L. HHCB concentrations in effluent ranged from 0.45 to 4.79 μg/L with a mean of 1.86 ± 1.01 μg/L. AHTN concentrations in sludge ranged from 0.65 to 15.0mg/kg dw (dry weight) with a mean and standard deviation being 3.69 ± 2.57 mg/kg dw, while HHCB sludge concentrations were between 4.1 and 91 mg/kg with a mean of 34.0 ± 23.1mg/kg dw. Measured concentrations of AHTN and HHCB were significantly correlated with each other in both effluent and sludge. The concentrations of HHCB in both effluent and sludge were approximately an order of magnitude higher than those for AHTN, consistent with 2011 usage levels. The highest measured effluent concentrations for both AHTN and HHCB were below their respective freshwater PNECs (predicted no effect concentrations), indicating a negligible risk to biological communities below WWTPs, even in the absence of upstream dilution. Moreover, the large number of effluents and sludges sampled provides a statistical distribution of loadings that can be used to develop more extensive probabilistic exposure assessments for WWTP mixing zones and sludge amended soils.