Un Hyuk Yim

Horizontal and vertical distribution of PCBs and chlorinated pesticides in sediments from Masan Bay, Korea.

Horizontal and vertical distributions of organochlorine compounds (OCs) were determined in sediments from Masan Bay. The concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), HCB, hexachlorocyclohexanes (HCHs) and chlordane related compounds (CHLs) in sediments were in the range of 1.24-41.4, 0.28-89.2, 0.02-0.59, nd-1.03, and nd-2.56 ng/g, respectively. The spatial distribution of OCs showed a negative gradient from the inner of the bay to outer part of the bay, indicating that the source of OCs was probably located inside the bay. Compositional pattern of PCB congeners showed a relatively high concentration of high-chlorinated congeners in the inner part of the bay and a relatively low concentration of low-chlorinated congeners in the outer part. In sediment core from Masan Bay maximum concentrations of PCBs and DDTs are observed in the subsurface samples and correspond to an age of early 1980s and late 1960s. The concentration profiles of PCBs and DDTs in sediments of Masan Bay appear to correspond to use of PCBs and DDTs in Korea.

Geographical distribution and accumulation features of organochlorine residues in bivalves from coastal areas of South Korea.

As a part of Mussel Watch Program in Korea, the contamination levels and accumulation features of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed for 82 bivalve samples collected from 66 sites along the entire coast of Korea. The dry weight based sigmaPCBs and sigmaOCPs ranged from 4.4 ng g(-1) to 422.0 ng g(-1) (geometric mean = 36.9 ng g(-1)) and from 9.95 ng g(-1) to 131.37 (34.88) ng g(-1), respectively. PCB was predominant in Korean coast, followed by DDTs, HCHs, and Chlordanes. From the observed log normal distribution of PCB and each OCP, low- and high-levels were defined as geometric mean +/- 1 S.D., respectively. The levels at the sites near urban and/or industrial areas often exceeded the high-levels and the spatial distributions of sigmaDDTs and sigmaCHLs were correlated with that of sigmaPCBs, indicating terrestrial input pathways. Even distribution of sigmaHCHs suggested a possibility of atmospheric input pathway of HCHs. The observed isomer ratios of DDTs, HCHs, and CHLs indicated that aging has occurred.

Fingerprint and weathering characteristics of stranded oils after the Hebei Spirit oil spill.

After the Hebei Spirit oil spill in December 2007, mixtures of three types of Middle East crude oil were stranded along 375 km of coastline in Western Korea. Stranded oils were monitored for their identity and weathering status in 19 stations in three provinces. The results obtained using a weathering model indicated that evaporation would be a dominant weathering process immediately after the spill and the sequential changes of chemical composition in the field verified this prediction positively. In the early stages of weathering, the half-life of spilled oil was calculated to be 2.6 months. Tiered fingerprinting approaches identified background contamination and confirmed the identity of the stranded oils with the spill source. Double ratios using alkylated phenanthrenes and dibenzothiophenes in samples after the spill clearly reveal the impact of weathering on oil. However, to derive defensible fingerprinting for source identification and allocation, recalcitrant biomarkers are extremely useful. Weathering status of the stranded oils was evaluated using composition profiles of saturated hydrocarbons, polycyclic aromatic hydrocarbons and various weathering indices. Most samples collected 8 months after the spill were categorized in either the advanced or extreme weathering states. Gradual increase in toxic components in the residual oil through weathering emphasizes the need for adaptive ecotoxicological approaches.

Hebei Spirit oil spill monitored on site by fluorometric detection of residual oil in coastal waters off Taean, Korea.

The spatiotemporal distributions of dissolved and/or dispersed oil in seawater and pore water were monitored on site by fluorometric detection method after the Hebei Spirit oil spill. The oil concentrations in intertidal seawater, 15 days after the spill, were as high as 16,600 microg/L and appeared to decrease below the Korean marine water quality standard of 10 microg/L at most sites 10 months after the spill. Fluorometric detection of oil in pore water was introduced to eliminate the effects of grain size for the quantification of oil in sediments and to better explain spatial and temporal distribution of oil pollution at sandy beaches. The fluorescence detection method was compared with the conventional laboratory technique of total petroleum hydrocarbon analysis using gas chromatography. The method of fluorescence detection of oil was capable of generating results much faster and more cost-effectively than the traditional GC technique.

Distribution characteristics of nonylphenolic chemicals in Masan Bay environments, Korea

To understand the distribution characteristics of nonylphenolics and sterols, samples such as in creek water, sea surface water, waste water treatment plant (WWTP) effluent water, sediment and mussel were collected and analyzed. The principal analytes are nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), nonylphenol diethoxylate (NP2EO), coprostanol (5beta) and cholestanol (5alpha). All these target pollutants showed 100% detection frequency in all of the samples analyzed. Total concentration of nonylphenolic compounds ranged from 334 to 3628ngl(-1) (average: 1331ngl(-1)) in creek water, from 15 to 36400ngl(-1) (average: 1013ngl(-1)) in sea surface water, from 131 to 2811ngg(-1) dry weight (average: 581ngg(-1) dry weight) in sediment and from 50.5 to 289ngg(-1) dry weight (average: 139ngg(-1) dry weight) in mussel. For water samples, levels of nonylphenolics determined in summer season were higher than those in spring season. Among them, nonylphenol and NP1EO was dominant in creek water and seawater, respectively. The highest concentration was recorded in sediment near a WWTP effluent outlet. And high levels of nonylphenolics and sterols were found in about 3km area surrounding WWTP effluent outlet. Coefficient of linear regression (R(2)) for NP in mussel and in sediment was 0.90. Similarly good correlation (R(2)=0.98) was obtained between concentration in water and in mussel indicating that a steady state has been reached in this bay. The calculated bio concentration factor (BCF=2990) for NP in Masan Bay agrees well with reported values in the literature.

Biomarker responses in pelagic and benthic fish over 1 year following the Hebei Spirit oil spill (Taean, Korea)

After the Hebei Spirit oil spill incident (7th December, 2007) in the west coast of Korea, contamination of biliary PAH metabolite and hepatic biomarkers in a pelagic and a benthic fish was monitored for 1 year. Concentrations of 16 PAHs and alkylated PAHs in fish muscle were highest (22.0 ng/g d.w. for 16 PAHs and 284 ng/g d.w. for alkylated PAHs) at 5 days after the spill and then decreased rapidly to background levels at 11 months after the spill. Fish from the oiled site had elevated biliary PAH metabolite concentrations immediately after the spill; these declined steadily in both species, but were still above reference site concentrations 2 months after the spill. Oiled-site fish showed hepatic CYP 1A induction whose trend closely followed those of biliary PAH metabolite concentrations, implying continuous exposure to PAHs. Brain acetylcholinesterase activity was not related to oil exposure.

Persistent organochlorine residues in estuarine and marine sediments from Ha Long Bay, Hai Phong Bay, and Ba Lat Estuary, Vietnam

To assess the organochlorine contamination in the northeast coastal environment of Vietnam, a total of 41 surface sediments were collected from Ha Long Bay, Hai Phong Bay, and Ba Lat estuary, and analyzed for their organochlorine content. Organochlorine compounds (OCs) were widely distributed in the Vietnamese coastal environment. Among the OCs measured, DDT compounds predominated with concentrations ranging from 0.31 to 274 ng g(-1). The overall contamination level of DDTs in coastal sediments from northern Vietnam is comparable with those from other Asian countries. However, concentrations exceeding 100 ng g(-1) are comparable with high concentrations reported from India and China, the largest DDT consumers in the world. The overall concentrations of PCBs, HCHs, and chlordanes in surface sediments were in the ranges of 0.04-18.71 ng g(-1), not detected (n.d.) - 1.00 ng g(-1), and n.d. - 0.75 ng g(-1), respectively. Ha Long Bay and Hai Phong Bay were relatively more contaminated with DDTs and PCBs than other regions, respectively. In contrast, the distribution of HCHs was relatively homogeneous. OCs contamination in the coastal environment of Vietnam is closely related to shipping and industrial activities. The levels of DDT compounds in harbors and industrial areas exceeded their sediment quality guideline values suggested by Environment Canada [CCME (Canadian Council of Ministers of the Environment), 2002. Canadian sediment quality guidelines for the protection of aquatic life. In: Canadian Environmental Quality Guidelines. Canadian Council of Ministers of the Environment, Winnipeg, MB] and Australian and New Zealand [ANZECC and ARMCANZ, 2000. National water quality management strategy. Paper No. 4, Australian and New Zealand Guidelines for Fresh and Marine Water Quality, vol. 1, The Guidelines. Australia. Document: http://www.deh.gov.au/water/quality/nwqms/volume1.html], indicating that adverse effects may occur to marine species in that areas.

Petroleum hydrocarbon contaminations in the intertidal seawater after the Hebei Spirit oil spill ― Effect of tidal cycle on the TPH concentrations and the chromatographic characterization of seawater extracts

In December 2007, the oil tanker Hebei Spirit released approximately 12,547,000 L of crude oil off the west coast of Korea, impacting more than 375 km of coastline. The seawater TPH concentrations immediately after the spill ranged from 1.5 to 7310 μg L⁻¹, with an average of 732 μg L⁻¹. The concentrations appeared to decrease drastically to 2.0-224 μg L⁻¹ in one month after the spill. The TPH concentrations in seawater fluctuated with time thereafter because of the remobilization of oil by continuing shoreline cleanup activities and subsequent wave/tidal actions. Seawater TPH concentrations were much higher during high tide than during low tide due to the resuspension of stranded oil. The variation of TPH levels in seawater also matched the spring-neap tidal cycle in the study areas for the first three weeks of the study. Comparisons of the gas chromatograms of the seawater with the water accommodated fraction and the cargo oil indicated that seawater samples were contaminated mainly by the dispersed droplets of spilled oil. One year of monitoring revealed that the oil content in seawater had clearly decreased at most sites, although some regional fluctuations of oil contamination were noted until June 2008.

Biochemical changes in rockfish, Sebastes schlegeli, exposed to dispersed crude oil.

This paper describes the response of the ovoviviparous rockfish, Sebastes schlegeli, to hydrocarbons in the water-accommodated fraction (WAF) of crude oil, in the presence or absence of oil dispersants. Concentrations of cytochrome P-450 1A (CYP1A) and levels of its catalytic activity ethoxyresorufin O-de-ethylase (EROD) in rockfish exposed to WAF at concentrations of 0.1% and 1% were significantly increased by the addition of a dispersant, Corexit 9500 after 48 h exposure. After 72 h exposure, the levels of CYP1A and EROD activity were significantly increased in 0.1% and 0.01% chemically enhanced WAF (CEWAF) (Corexit 9500 and Hiclean II dispersant). Bile samples from fish exposed to WAF alone had low concentrations of hydrocarbon metabolites, exemplified by 1-hydroxypyrene. After 72 h exposure, hydrocarbon metabolites in bile from fish exposed to WAF in the presence of either Corexit 9500 or Hiclean II were significantly higher compared with fish exposed to WAF alone or control fish. These experiments confirm that the use of oil dispersants will increase the exposure of ovoviviparous fish to hydrocarbons in oil.

Assessment of TBT and organic booster biocide contamination in seawater from coastal areas of South Korea.

Seawater samples from major enclosed bays, fishing ports, and harbors of Korea were analyzed to determine levels of tributyltin (TBT) and booster biocides, which are antifouling agents used as alternatives to TBT. TBT levels were in the range of not detected (nd) to 23.9 ng Sn/L. Diuron and Irgarol 1051, at concentration ranges of 35-1360 ng/L and nd to 14 ng/L, respectively, were the most common alternative biocides present in seawater, with the highest concentrations detected in fishing ports. Hot spots were identified where TBT levels exceeded environmental quality targets even 6 years after a total ban on its use in Korea. Diuron exceeded the UK environmental quality standard (EQS) value in 73% of the fishing port samples, 64% of the major bays, and 42% of the harbors. Irgarol 1051 levels were marginally below the Dutch and UK EQS values at all sites.