Rain amplification of persistent organic pollutants

• Published in: Environmental Science & Technology
• Main Authors: Casas Papell, Gemma, Martínez Varela, Alicia, Vila-Costa, Maria, Jimenez, Begoña, Dachs Marginet, Jordi
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Àrees temàtiques de la UPC::Desenvolupament humà i sostenible::Degradació ambiental; Air > Pollution; Organic water pollutants; Persistent pollutants; Wet deposition; Snow; Scavenging; Amplification; Antarctica; PFASs; OPEs; PAHs; PCBs; PBDEs; Aire > Contaminació; Contaminants orgànics de l'aigua; Contaminants persistents; Antarc*
• Online Access: http://hdl.handle.net/2117/381343; https://doi.org/10.1021/acs.est.1c03295

Scavenging of gas- and aerosol-phase organic pollutants by rain is an efficient wet deposition mechanism of organic pollutants. However, whereas snow has been identified as a key amplification mechanism of fugacities in cold environments, rain has received less attention in terms of amplification of organic pollutants. In this work, we provide new measurements of concentrations of perfluoroalkyl substances (PFAS), organophosphate esters (OPEs), and polycyclic aromatic hydrocarbons (PAHs) in rain from Antarctica, showing high scavenging ratios. Furthermore, a meta-analysis of previously published concentrations in air and rain was performed, with 46 works covering different climatic regions and a wide range of chemical classes, including PFAS, OPEs, PAHs, polychlorinated biphenyls and organochlorine compounds, polybromodiphenyl ethers, and dioxins. The rain–aerosol (KRP) and rain–gas (KRG) partition constants averaged 105.5 and 104.1, respectively, but showed large variability. The high field-derived values of KRG are consistent with adsorption onto the raindrops as a scavenging mechanism, in addition to gas–water absorption. The amplification of fugacities by rain deposition was up to 3 orders of magnitude for all chemical classes and was comparable to that due to snow. The amplification of concentrations and fugacities by rain underscores its relevance, explaining the occurrence of organic pollutants in environments across different climatic regions. Postprint (published version)