Occurrence of polycyclic musks in wastewater and receiving water bodies and fate during wastewater treatment

The occurrence of cashmerane (DPMI), celestolide, phantolide, traesolide (ATII), galaxolide (HHCB) and tonalide (AHTN) in sewage and surface waters and their fate during wastewater treatment and anaerobic sludge digestion is investigated. AHTN and HHCB are the most important representatives and influent concentrations of 0.41–1.8 and 0.9–13 μg L−1 are observed. DPMI is detected in influent and effluent samples but in notably lower concentrations than AHTN and HHCB. Major sources of polycyclic musks are households, whereas industrial emitters seem to be of minor importance. This conclusion is supported by the analysis of selected industrial wastewaters (metal, textile and paper industry). Specific emissions of 0.36 ± 0.19 and 1.6 ± 1.0 mg cap−1 d−1 for AHTN and HHCB are calculated. Overall removal efficiencies between approx 50% and more than 95% are observed during biological wastewater treatment and removal with the excess sludge is the major removal pathway. Log KD values of 3.73–4.3 for AHTN, 3.87–4.34 for HHCB and 2.42–3.22 for DPMI are observed in secondary sludge. During sludge digestion no or only slight removal occurred. Mean polycyclic musk concentrations in digested sludge amounted to 1.9 ± 0.9 (AHTN), 14.2 ± 5.8 (HHCB), 0.8 ± 0.4 (ATII) and 0.2 ± 0.09 (DPMI) mg kg−1 dry matter. In the receiving water systems a comparable distribution as during wastewater treatment is observed. AHTN, HHCB and DPMI are detected in surface waters (ND (not detected) – < 0.04, ND – 0.32 and ND – 0.02 μg L−1) as well as AHTN and HHCB in sediments (ND – 20, ND – 120 μg kg−1). For HHCB an apparent KOC value of 4.1–4.4 is calculated for sediments. Major source for polycyclic musks in surface waters are discharges from wastewater treatment plants. For HHCB and DPMI 100% of the load observed in the sampled surface waters derive from discharges of treated wastewater.

Research highlights
► Households are the major sources for polycyclic musks in wastewater.
► Polycyclic musks are widely removed during wastewater treatment.
► Adsorption to the sludge is the relevant removal pathway.
► Wastewater discharges are major sources for polycyclic musks in rivers.
► In freshwater systems partitioning to solids and accumulation on sediments.