title: Emission of poly and perfluoroalkyl substances, UV-filters and siloxanes to air from wastewater treatment plants.
abstract: The potential of wastewater treatment plants (WWTPs) to act as sources of poly and perfluoroalkyl substances (PFASs), volatile methyl siloxanes (VMSs) and organic UV-filters to the atmosphere was investigated. Target compounds included: PFASs (fluorotelomer alcohols (FTOHs), perfluorooctane sulfonamides/sulfonamidoethanols (FOSAs/FOSEs), perfluroalkyl sulfonic acids (PFSAs) and perfluroalkyl carboxylic acids (PFCAs)), cyclic VMSs (D3 to D6), linear VMSs (L3 to L5) and eight UV-filters. Emissions to air were assessed at eight WWTPs using paired sorbent-impregnated polyurethane foam passive air samplers, deployed during summer 2013 and winter 2014. Samplers were deployed on-site above the active tank and off-site as a reference. Several types of WWTPs were investigated: secondary activated sludge in urban areas (UR-AS), secondary extended aeration in towns (TW-EA) and facultative lagoons in rural areas (RU-LG). The concentrations of target compounds in air were ∼1.7-35 times higher on-site compared to the corresponding off-site location. Highest concentrations in air were observed at UR-AS sites while the lowest were at RU-LG. Higher air concentrations (∼2-9 times) were observed on-site during summer compared to winter, possibly reflecting enhanced volatilization due to higher wastewater temperatures or differences in influent wastewater concentrations. A significant positive correlation was obtained between concentrations in air and WWTP characteristics (influent flow rate and population in the catchment of the WWTP); whereas a weak negative correlation was obtained with hydraulic retention time. Emissions to air were estimated using a simplified dispersion model. Highest emissions to air were seen at the UR-AS locations. Emissions to air (g/year/tank) were highest for VMSs (5000-112,000) followed by UV-filters (16-2000) then ΣPFASs (10-110).
authors.affiliation: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada. Electronic address: Mahiba.shoeib@canada.ca.
authors.forename: Mahiba
authors.initials: M
authors.lastname: Shoeib
authors.affiliation: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Schuster
authors.affiliation: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada.
authors.forename: Cassandra
authors.initials: C
authors.lastname: Rauert
authors.affiliation: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada.
authors.forename: Ky
authors.initials: K
authors.lastname: Su
authors.affiliation: Emerging Priorities Division, Science and Technology Branch, Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, Ontario L7S 1A1, Canada.
authors.forename: Shirley-Anne
authors.initials: SA
authors.lastname: Smyth
authors.affiliation: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada.
authors.forename: Tom
authors.initials: T
authors.lastname: Harner
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001272:Atmosphere; D004784:Environmental Monitoring; D005466:Fluorocarbons / Q000032:analysis*; D011140:Polyurethanes; D012722:Sewage / Q000737:chemistry; D012833:Siloxanes / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis; D062065:Wastewater / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D005466:Fluorocarbons; D011140:Polyurethanes; D012722:Sewage; D012833:Siloxanes; D055549:Volatile Organic Compounds; D062065:Wastewater; C028279:polyurethane foam
keywords: Emission to air; Organic UV-filters; Passive air samples; Perfluoroalkyl substances; Volatile methyl siloxanes; Wastewater treatment plants