Abstract
Major urban and industrial centers increase loadings of semi-volatile organic compounds (SVOCs) to proximate sea waters through riverine transport, atmospheric deposition via dry particle deposition, wet deposition, and air-sea gas exchange. In addition to acting as sinks for SVOCs, oceans can act as sources of SVOCs to coastal atmospheres and play important roles in the global biogeochemistry of SVOCs. Particle-sorbed SVOCs can settle to the ocean surface by dry particle deposition, a uni-directional advective transport process from the atmosphere to the water, the removal rate by which is a function of the physical and chemical properties of the aerosols and bound pollutants, meteorological conditions and surface characteristics. In addition, SVOCs are removed from the atmosphere and transported to the waters by precipitation scavenging of atmospheric vapors and particles, which are incorporated into the rain within or below the clouds. After SVOCs are deposited into the bulk seawater, water-column partitioning can affect the distribution of pollutants between the dissolved aqueous and the solid phases and eventually impact the fate of these compounds in oceans. Other than the abovementioned processes, air-sea exchange can make SVOCs diffuse across the air-sea interface; however, the sea surface microlayer (SML), a unique compartment at the air-sea boundary defined operationally as the upper millimeter (1 ∼ 1000 μm) of the sea surface, has large storage capacity to delay the transport of SVOCs across the interface.This article reports the dry particle deposition and wet deposition of selected SVOCs based on an extensive set of yearly data collected in Singapore. Singapore, a representative country of Southeast Asia (SEA), is a small but highly developed island with dense industrial parks in the Southwestern part, where the terrestrial sources affect the surrounding coasts. In this study, Singapore’s Southern coastline was chosen during the Northeast monsoon season to evaluate if this coastal area acts a sink or source for selected SVOCs via air-sea diffusive exchange as well as to investigate the SML enrichment effect.
Highlights
The atmosphere is strongly coupled with the terrestrial and marine environments especially in tropical areas because of strong vertical movement of air and abundant rainfall
In Singapore’s coastal area, the monthly dry deposition fluxes for Polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were in the range of 46.0 ∼ 275.6 μg m−2 month−1, 60.7 ∼ 906.1 ng m−2 month−1 and 3.1 ∼ 93.1 ng m−2 month−1, respectively
The monthly wet deposition flux for PAHs and OCPs ranged from 70.0 ∼ 363.5 μg m−2 month−1 and 4.7 ∼ 39.9 μg m−2 month−1, respectively
Summary
The atmosphere is strongly coupled with the terrestrial and marine environments especially in tropical areas because of strong vertical movement of air and abundant rainfall. SVOCs, which include a wide range of priority pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), are ubiquitously present in air, water, soil and biota, and even could be found in remote and pristine areas such as the Arctic [4,5,6,7]. These three groups of SVOCs, namely persistent organic pollutants (POPs), are very resistant to natural breakdown processes and extremely stable and long-lived in the environment. The persistence of PCBs coupled with their ability to bioaccumulate in food chains has caused great environmental damage [48]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
