Fugacity gradients of hydrophobic organics across the air-water interface measured with a novel passive sampler.
Mass transfer of hydrophobic organic contaminants (HOCs) across the air-water interface is an important geochemical process controlling the fate and transport of HOCs at the regional and global scales. However, few studies have characterized concentration or fugacity profiles of HOCs near both sides of the air-water interface, which is the driving force for the inter-compartmental mass transfer of HOCs. Herein, we introduce a novel passive sampling device which is capable of measuring concentration (and therefore fugacity) gradients of HOCs across the air-water interface. Laboratory studies indicated that the escaping fugacity values of polycyclic aromatic hydrocarbons (PAHs) from water to air were negatively correlated to their volatilization half-lives. Results for field deployment were consistent between the passive sampler and an active method, i.e., a combination of grab sampling and liquid-liquid extraction. In general, the fugacity profiles of detected PAHs were indicative of an accumulation mechanism in the surface microlayer of the study regions (Haizhu Lake and Hailing Bay of Guangdong Province, China), while p,p'-DDD tended to volatilize from water to the atmosphere in Hailing Bay. Furthermore, the fugacity profiles of the target analytes increased towards the air-water interface, reflecting the complexity of environmental behavior of the target analytes near the air-water interface. Overall, the passive sampling device provides a novel means to better characterize the air-water diffusive transfer of HOCs, facilitating the understanding of the global cycling of HOCs.
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Chen-Chou
CC
Wu
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Yao
Y
Yao
School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China. Electronic address: baolianjun@jnu.edu.cn.
Lian-Jun
LJ
Bao
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Feng-Chang
FC
Wu
Richardson College for the Environment, Department of Environmental Studies and Sciences and Department of Chemistry, University of Winnipeg, Winnipeg, Manitoba R3B 2E9, Canada.
Charles S
CS
Wong
Laboratory of Earth Surface Processes, College of Urban and Environmental Science, Peking University, Beijing 100871, China.
Shu
S
Tao
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; School of Environment, Guangzhou Key Laboratory of Environmental Exposure and Health, and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou 510632, China.
Eddy Y
EY
Zeng
D000393:Air Pollutants / Q000032:analysis*; D002681:China; D004058:Diffusion; D004784:Environmental Monitoring / Q000379:methods; D057927:Hydrophobic and Hydrophilic Interactions; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D014835:Volatilization; D014874:Water Pollutants, Chemical / Q000032:analysis*
D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical
Air-water interface; Fugacity gradient; Hydrophobic organic contaminants; Mass transfer; Passive sampler