Oil-Suspended Particulate Matter Aggregates: Formation Mechanism and Fate in the Marine Environment

Andrew Loh,심원준,하성용,임운혁 한국해양과학기술원 2014 Ocean science journal Vol.49 No.4

Oil suspended particulate matter (SPM) aggregates (OSA) are naturally occurring phenomena where oil droplets and particles interact to form aggregates. This aggregation could aid cleanup processes of oil contaminated waters. When OSA is formed, it makes oil less sticky and would facilitate the dispersion of oil into the water column. Increased oil-water surface contact by OSA formation enhances biodegradation of oil. Its applicability as a natural oil clean-up mechanism has been effectively demonstrated over past decades. There are many factors affecting the formation of OSA and its stability in the natural environment that need to be understood. This review provides a current understanding of (1) types of OSA that could be formed in the natural environment; (2) controlling factors and environmental parameters for the formation of OSA; (3) environmental parameters; and (4) fate of OSA and its applicability for oil spill remediation processes.

Chemical Characterization of PM₁ in the East Sea using High Resolution Aerosol Mass Spectrometer

Andrew Loh,김동휘,안준건,황규철,임운혁 한국대기환경학회 2020 한국대기환경학회 학술대회논문집 Vol.2020 No.10

유류-부유물질 응집체를 이용한 조간대 부유식자의 미확인 오염노출경로 평가

Andrew Loh,심원준(W.J.Shim),하성용(S.Y.Ha),안준건(J.G. Ahn),임운혁(U.H.Yim) 한국해양환경·에너지학회 2015 한국해양환경·에너지학회 학술대회논문집 Vol.2015 No.5

A Data-Driven Binary-Regression Framework for Rapid Screening of Marine Fuel Oil

Loh Andrew,임운혁 한국해양과학기술원 2023 Ocean science journal Vol.58 No.1

Despite the decreases in the number of oil spill cases over the years, marine oil pollution caused by indirect transfer of oil combustion emissions has drastically escalated with global shipping activities. As a response, a global initiative to control ship emissions, particularly focusing on sulfur oxide, was established by the International Maritime Organization. As part of the enforcement plan, time and resource consuming chemical analysis methods for the inspection of fuel oil have become essential to ensure that vessels comply with the regulation. In order to increase the efciency of chemical analysis, ultraviolet–visible spectroscopy coupled with chemometrics was developed for the characterization of oil. This study aimed to develop a rapid yet accurate oil physicochemical property screening method by combining simplifed spectrometry techniques coupled with chemometrics. A partial least squares model for physicochemical properties such as sulfur content, viscosity, and saturate, aromatic, as well as polar fraction, was calibrated with 330 spectra and validated using 100 spectra. Prediction models were highly accurate with R2 and root mean square error of prediction (RMSEP) values ranging from 0.80–0.96 and 0.10–3.08, respectively. With an R2 value of 0.86, high correlations amongst predicted variables further validated the robustness of models. A quantitative comparison between the time needed for oil characterization through data-driven binary regressions and standardized chemical analysis methods indicated that data-driven binary regressions are 94% more efcient than standardized chemical analysis methods. This study demonstrated that simplifed spectroscopy techniques can be powerful tools for rapid screening of environmental pollution when coupled with chemometrics.

A preliminary study on the role of suspended particulate matter in the bioavailability of oil-derived polycyclic aromatic hydrocarbons to oysters

Loh, Andrew,Yim, Un Hyuk,Ha, Sung Yong,An, Joon Geon Elsevier 2018 Science of the Total Environment Vol.643 No.-

<P><B>Abstract</B></P> <P>Suspended particulate matter (SPM) refers to fine-grained materials that are suspended in water columns. By providing a surface for the adsorption of non-polar organic compounds, SPM is a carrier for persistent and toxic contaminants. A wide range of organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), can be adsorbed onto SPM. The formation of particle-associated PAHs can sequentially increase the potential for exposure to and bioaccumulation by organisms. Until recently, most oil exposure studies were performed using freely dissolved and dispersed forms, and therefore the role of SPM in influencing the bioavailability and bioaccumulation of PAHs has not been considered. This study found that SPM influences the bioavailability of petrogenic PAHs in the water column and their potential for accumulation in oysters. SPM significantly enhanced the water column entrainment of petrogenic PAHs, thus increasing the potentials for uptake by exposed organisms. PAHs in the water column was highest from mechanically dispersed oil (MDO; 2.27 μg/mL) ≥ oil-SPM aggregate (OSA; 1.96 μg/mL) > water accommodated fraction (WAF; 0.19 μg/mL) but the percentage of PAHs accumulated in oysters were highest from WAF (18.3%) > MDO (14.2%) > OSA (9.62%). Despite the high water column available PAHs, oysters exposed to SPM-associated oil accumulated PAHs at half the accumulation efficiency compared with those exposed to PAHs without SPM.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SPM increased entrainment of dissolved and dispersed PAHs in the water column. </LI> <LI> SPM significantly increased uptake of PAHs by oysters through ingestion of particle-bound PAHs. </LI> <LI> Strong SPM-PAHs bonds retarded dissolution of PAHs into the water column. </LI> <LI> SPM played significant roles on inhibiting accumulation of PAHs by oysters. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fate of residual oils during remediation activities after the <i>Wu Yi San</i> oil spill

Loh, Andrew,Yim, Un Hyuk,Ha, Sung Yong,An, Joon Geon,Shankar, Ravi PERGAMON 2019 MARINE POLLUTION BULLETIN Vol.138 No.-

<P><B>Abstract</B></P> <P>In this study, the fate of residual oils was investigated during remediation activities for a year after the <I>Wu Yi San</I> oil spill. Microscope observations showed that relatively large amounts of oil-suspended particulate matter aggregate (OSA) were formed. Negatively buoyant OSA was the dominant form (>95%), followed by neutrally (~5%) and positively buoyant (<1%) forms. To elucidate the dominance of negative buoyancy OSA, physicochemical properties of the mineral and residual oils were identified. Chemical analysis showed that the weathering percentage of residual oils was 43.7 ± 2.59%, which was the driving factor for sedimentation of OSA. As the density of oil increased with weathering stages, the density of OSA also increased simultaneously. These results showed that, during mechanical remediation activities, resurfaced residual oils can form negative buoyancy OSA which tends to sink and transfers oil contaminants from intertidal to benthic environments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Resuspended residual oils formed oil-suspended particulate matter aggregate (OSA) during remediation activities. </LI> <LI> Dominant shape of OSA was oil coated particle with negative buoyancy. </LI> <LI> Highly weathered oil was the main cause of negative buoyancy OSA. </LI> <LI> Physical remediation activities can transfer residual oil from intertidal to subtidal in the form of OSA. </LI> </UL> </P>

A Review of the Effects of Particle Types on Oil-suspended Particulate Matter Aggregate Formation

Andrew Loh,임운혁 한국해양과학기술원 2016 Ocean science journal Vol.51 No.4

Oil-suspended particulate matter aggregate (OSA) can form naturally when oil and particles interact. The interaction between oil and suspended particulate matter makes oil less sticky, and facilitates its dispersion in the water column. The high oilwater surface contact enhances the biodegradation of oil and thus increases the efficiency of remediation processes. There are many factors that affect OSA formation, but, particle type is one of the most important. Because different particle types have different physical, chemical, and biological properties, their interactions with oil differ greatly. Particle properties such as interlayer spaces, hydrophobicity, surface charges, polarity, organic content, and size affect the interactions between materials and oil. These different interactions determine the type, buoyancy, size, and stability of OSA that forms, thus determining its fate in the environment. This review provides a current understanding of (1) OSA formation mechanisms, (2) sources and classes of marine materials, (3) oilparticle interactions, (4) material properties and their effects on oil interaction, and (5) future research needs.

Chemical Characterization of Sub-micron Aerosol Emissions from Ship Anchorage Zone of the Port of Busan

Andrew Loh,김동휘,안준건,황규철,최나린,임운혁 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

To investigate the time-resolved chemical evolution of PM₁ from anchorage zones of the Port of Busan, a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in Yeongdo, Busan, during 10<SUP>th</SUP> Sep –6<SUP>th</SUP> Oct 2020. Total mass concentrations of PM₁ aerosols varied significantly with air mass origins; eastern winds from sea breeze were lowest (6.64 μg·m<SUP>-3</SUP>) and western winds from anchorage zones were highest (14.5 μg·m<SUP>-3</SUP>). PMF identified one hydrocarbon-like OA (HOA) and two oxygenated OA (OOA) sources. HOA were highest from northeastern winds (40.3%) likely associated to combustion-related emissions from the Port of Busan. OOA components corresponding to less oxidized (SV-OOA; 38.6%) and more oxidized (LV-OOA; 41.4%) secondary OA (SOA) materials were proportionally higher from anchorage zone. Eastern winds showed dominance of LV-OOA (45.4%) components associated to oceanic origins. Three new particle formation events (NPE) were observed during low PM2.5 days. The average particle growth rate was 6.0 nm·h<SUP>-1</SUP> with significantly higher Ntotal particle counts on NPE than non-NPE days. Source composition profiles showed significant dominance of LV-OOA during NPE days indicating particle size growth corresponding to SOA.

연구선 기반 해양-대기 관측 시 자료의 활용방안 - 선박배출계수를 중심으로

황규철,안준건,Andrew Loh,김동휘,최나린,임운혁 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

연구선 기반 연구는 해양 및 대기 분야에서 많이 이용되고 있으며, 국내 연안에서부터 대양까지 연구의 범위 및 활용성이 확장됨에 따라 생성되는 방대한 자료의 활용방안에 대하여 고민해볼 필요가 있다. 일반적으로, 연구선 기반 연구는 많은 시간, 비용 그리고 인력을 요구하기 때문에, 자료의 가치가 높으며 자료의 수집 및 생성과정에서 고도의 기술력이 필요하다. 해양-대기 연구에서 가장 중요한 자료처리 과정은 연구선 자체의 배기가스 자료를 제외하는 것이며, 항해 중 뒤 바람이 강하게 불 때 발생할 수 있다. 해양-대기 연구에서는 이러한 자료를 “오염된 자료”로 판단하여 분석에서 제외한다. 전체 자료에서 20-30%가량의 “오염된 자료”가 발생하여 많은 자료 손실이 발생한다. 본 연구에서는 2019년 7월부터 2021년 3월까지 실시된 총 6회의 연구선(이사부호, 온누리호, 이어도호)운항 관측 결과 중 “오염된 자료”로 판단되어 분석에서 제외된 자료를 재활용하여 실제 운항조건에서 배출되는 대기오염물질의 선박 배출계수를 산정하였다. 배출계수 산정은 연료연소 기반 탄소수지법(carbon balance)을 이용하였으며, 관측장비 및 관측항목은 HR-ToF-AMS (PM1.0 내 화학조성), SMPS (입자수농도), Aethalometer (블랙카본), Dusttrak (PM10, PM2.5 농도), SIFT-MS (VOCs), CRDS (CO₂, CH₄,), AQMS (NO, NO₂, SO₂, O₃, CO)이다. 평균 배출계수는 30.6±12.5 g·(kg·fuel)<SUP>-1</SUP>이며, NOX (63%)의 배출이 지배적으로 나타났다.

Chemical and Physical Characteristics of Marine Aerosols in Offshore of South Korea

김동휘,안준건,ANDREW LOH JIN YI,황규철,임운혁 한국분석과학회 2020 학술대회논문집 Vol.2020 No.6