Mass Budget of Perfluorooctane Surfactants in Lake Ontario

Perfluorooctane surfactants have been reported in biota, , and air samples worldwide. Despite these reports, the environmental sources of these compounds remain. To address this gap in knowledge, an annual lake-wide mass budget of eight perfluorooctane surfactants developed for Lake Ontario. To determine the atmospheric to the mass budget, over-the-lake gas-phase air concentrations for N-EtFOSE and N-EtFOSA and-phase air concentrations for PFOS in any air are reported for the first time, with mean when present of 0. 5 ± 0. 32 (N-EtFOSE gas-phase), 1. 1 ± 0. 9 (N-EtFOSA gas-phase), and 6. 4 ± 3. 3 (PFOS particulate-phase) pg/m3. The mass budget finds from Lake Erie (14 361 ± 4489 kg Σperfluorooctane) and wastewater discharge (1762 ± 2697 kgΣperfluorooctane surfactants) to be the major sources, while through the St. Lawrence River is the dominant mechanism (22 727 ± 7060 kg/year Σperfluorooctane). Using the mass budget data, the steady and measured mean concentrations in the lake water the same at the 95% confidence level.