Brominated Persistent Organic Pollutants in Cloud/Fog Water: First Field Observations of Scavenging Behavior

Area of Science:

• Environmental Chemistry
• Atmospheric Science
• Pollutant Transport

Background:

• Cloud/fogwater is a critical, understudied pathway for persistent organic pollutant (POP) cycling and deposition.
• Brominated POPs (Br-POPs), including PBDEs and PBDD/Fs, are significant environmental contaminants.
• Understanding POP behavior in atmospheric water is crucial for assessing environmental risks.

Purpose of the Study:

• To conduct the first field-based measurements of Br-POPs in cloud/fogwater.
• To investigate the multiphase behavior and scavenging dynamics of Br-POPs.
• To assess the role of cloud/fogwater in the atmospheric removal and deposition of Br-POPs.

Main Methods:

• Field measurements of Br-POPs in cloud/fogwater collected during Northeast monsoon seasons (2018-2020) in northern Taiwan.
• Analysis of polybrominated diphenyl ethers (PBDEs) and polybrominated dibenzo-p-dioxins and furans (PBDD/Fs).
• Multiphase partitioning analysis and calculation of scavenging ratios and coefficients.

Main Results:

• BDE-209 was the dominant Br-POP homologue, with higher concentrations observed in 2018.
• Concentrations varied between particulate and aqueous fractions, with higher levels in 2018 suggesting stronger monsoon influence and enhanced scavenging.
• Multiphase partitioning indicated non-equilibrium conditions, with efficient Br-POP scavenging into droplets; lower-brominated congeners favored the aqueous phase, while highly brominated ones favored the particle phase.

Conclusions:

• Cloud/fogwater is an effective pathway for the atmospheric removal and deposition of Br-POPs.
• The study reveals the multiphase behavior and scavenging dynamics of Br-POPs in atmospheric water.
• Findings highlight the importance of cloud/fogwater in regional contaminant cycling and transport.