Wet Deposition and Photodegradation of Perfluoroalkyl Carboxylates and Fluorotelomer Alcohols: Distribution Pathways from Air to Water Environment

Abstract

This study aims to investigate the distribution of perfluoroalkyl carboxylates (PFCAs) and fluorotelomer alcohols (FTOHs) from air to water environment. Air and rainwater samples were collected in Kyoto, Japan. Eight PFCAs (C5 -C12) and three FTOHs in the samples were quantified by HPLC-MS/MS and GC-MS, respectively. All PFCAs were detected in the air (140 pg/m 3 ) and rainwater (16.4 ng/L) samples, indicating their wet deposition from air in the study area. Flux of PFCAs via wet deposition ranged between 120 -670 ng/m 2 in each rainfall event. All FTOHs were detected in the air (1,800 pg/m 3 ) but they were below the detection limits in rainwater (< 6.9 -8.7 ng/L). The results indicated that FTOHs were difficult to be wet deposited from the air. Most of PFCAs in rainwater increased after a few weeks of sunlight exposure, which suggests degradation of their precursor compounds. Photodegradation of 8:2 FTOH was confirmed by a UV (254 nm) irradiation experiment. Five PFCAs (C5 -C9) were identified as degradation products of 8:2 FTOH, with the production rate of 1.79% at molar basis. This study demonstrated distribution pathways of PFCAs and their precursors in environment via wet deposition and photodegradation, and confirmed that atmosphere is an important compartment for the distribution of these compounds to water environment.