Seung-Kyu Kim

Distribution of perfluorochemicals between sera and milk from the same mothers and implications for prenatal and postnatal exposures

The levels of six perfluorocarboxylates (PFCAs), four perfloroalkylsulfonates (PFASs), and one sulfonamide were measured in paired samples of maternal serum, umbilical cord serum, and breast milk. The maternal and cord sera were strongly correlated with each other for all measured compounds (r>0.5 and p<0.01). Nevertheless, there was a significant difference in compound composition profile between the two sera matrices, with a more depletion of the longer chain compounds in cord serum. The transfer efficiency values from maternal to cord serum (TFCS/MS) decreased by 70% with each increasing unit of -CF2 chain within a PFCA group, and for perfluorooctanesulfonate (PFOS), by a half compared to perfluorooctanoate (PFOA). In contrast to the strong correlation in concentrations between the two sera matrices, the pattern of compounds in breast milk differed considerably with those in sera. Accordingly, compound- and matrix-specific transfer must be considered when assessing prenatal and postnatal exposure.

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.

Polybrominated diphenyl ethers and synthetic musks in umbilical cord Serum, maternal serum, and breast milk from Seoul, South Korea

Fetal and maternal exposure levels of two emerging pollutants, polybrominated diephenyl ethers (PBDEs) and synthetic musks, were measured in Korean general population to assess prenatal and postnatal exposures in infants. For this purpose, paired samples of breast milk, maternal and cord blood were collected from 20 Korean women in 2007. In comparison to data from other countries and previous data from Korea, relatively higher and gradually increasing concentrations for PBDEs were found in Korean breast milk (< LOQ to 590 ng g(-1) lipid wt; median=90 ng g(-1)). Differences in PBDEs and musk concentrations were found among age groups and parity levels. PBDEs concentrations in breast milk were lower in the younger mothers and/or the mothers with multiple parities, while these trends were not found for musks. Compared with PBDEs, concentrations of musks were significantly lower in breast milk than in serum and a little correlation in concentrations among the three human biological matrices were observed. The differences in the profiles of musks relative to PBDEs were due to different clearance rates between these two compounds. The average hazard quotients (HQs) for daily intake of PBDEs by infants via lactation were 0.62, 0.42, and 0.19 for BDE-47, BDE-99, and BDE-153, respectively.

Wastewater treatment plants (WWTPs)-derived national discharge loads of perfluorinated compounds (PFCs).

The discharge of perfluorinated compounds (PFCs) was investigated for 15 wastewater treatment plants (WWTPs), comprising 25% of total domestic wastewater and 23% of total industrial wastewater produced in Korea. PFCs concentrations in influent, effluent, and sludge were greater in industrial wastewater than in the majority of domestic wastewater. Individual PFCs were found to have differing industrial sources, with perfluorocarboxylates used in fabric/textiles, paper-mill, and dyeing industries, and perfluoroalkylsulfonates occurring in oil/chemical and metal-plating/processing industries. Total WWTP-derived national discharge loads were calculated based on the average concentrations in effluents and the total volume of wastewaters produced in Korea. The average WWTP-derived national discharge loads of individual PFCs were 0.04-0.61 ton/year, with 63% of perfluorooctanoate being from domestic wastewater, and 75% of perfluorooctanesulfonate being from industrial wastewater. These estimates accounted for the majority of national emissions, based on measurements in major river mouths, indicating the major contribution of WWTPs to PFC occurrence in Korean aquatic environments. Both the per capita emission factor (μg/capita/day) for domestic discharge, and area-normalized national discharge loads (g/capita/km(2)/day) for all wastewaters were several factors lower in Korea than in Japan or Europe, which is consistent with the lower levels of human exposure to PFCs in Korea.

Emissions of halogenated compounds in East Asia determined from measurements at Jeju Island, Korea.

High-frequency in situ measurements at Gosan (Jeju Island, Korea) during November 2007 to December 2008 have been combined with interspecies correlation analysis to estimate national emissions of halogenated compounds (HCs) in East Asia, including the chlorofluorocarbons (CFCs), halons, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF(6)), and other chlorinated and brominated compounds. Our results suggest that overall China is the dominant emitter of HCs in East Asia, however significant emissions are also found in South Korea, Japan and Taiwan for HFC-134a, HFC-143a, C(2)F(6), SF(6), CH(3)CCl(3), and HFC-365mfc. The combined emissions of CFCs, halon-1211, HCFCs, HFCs, PFCs, and SF(6) from all four countries in 2008 are 25.3, 1.6, 135, 42.6, 3.6, and 2.0 kt/a, respectively. They account for approximately 15%, 26%, 29%, 16%, 32%, and 26.5% of global emissions, respectively. Our results show signs that Japan has successfully phased out CFCs and HCFCs in compliance with the Montreal Protocol (MP), Korea has started transitioning from HCFCs to HFCs, while China still significantly consumes HCFCs. Taiwan, while not directly regulated under the MP, is shown to have adapted the use of HFCs. Combined analysis of emission rates and the interspecies correlation matrix presented in this study proves to be a powerful tool for monitoring and diagnosing changes in consumption of HCs in East Asia.

Indoor and outdoor poly- and perfluoroalkyl substances (PFASs) in Korea determined by passive air sampler

Despite concerns to their increasing contribution to ecological and human exposure, the atmospheric levels of poly- and perfluoroalkyl substances (PFASs) have been determined mainly in Europe and North America. This study presents the indoor and outdoor air concentrations of volatile PFASs [fluorotelomer alcohols (FTOHs), and perfluoroalkyl sulfonamides/sulfonamidoethanols/sulfonamide ethyl acetate (FOSAs/FOSEs/FOSEA)] for the first time in Korean cities. In contrast to the good agreement observed for indoor FTOHs levels in Korea and Europea/North America, FOSAs/FOSEs levels were 10-100-fold lower in Korean indoor air, representing a cultural difference of indoor source. Korean outdoor air contained higher PFAS levels than indoor air, and additionally showed different PFAS composition profile from indoor air. Thus, indoor air would not likely be a main contributor to atmospheric PFAS contamination in Korea, in contrast to western countries. Inhalation exposure of volatile PFASs was estimated to be a minor contributor to PFOA and PFOS exposure in Korea.

Occurrence of perfluorooctanoate and perfluorooctanesulfonate in the Korean water system: Implication to water intake exposure

Perfluorinated compounds (PFCs) measured in surface running waters indicated the existence of different emission sources in eight main city basins. The tap water reflected the contamination pattern and levels in their corresponding source water basins. The daily intakes through tap water consumption ranged from <0.01 to 0.73 ng kg(-1) d(-1) for perfluorooctanoate (PFOA) and <0.01 to 0.08 ng kg(-1) d(-1) for perfluorooctanesulfonate (PFOS). Tap water intake-derived exposure accounted for 8.6%-101% (for PFOA) and while <10% (for PFOS) of total daily exposure, which was estimated from Korean serum concentrations using a pharmacokinetic model. Our findings indicate that tap water intake could be an important contributor to PFOA exposure in Korean populations; accordingly, additional efforts are necessary to improve the removal efficiency of perfluorinated compounds (PFCs) in the water purification process. However, more fundamentally the aim would be to reduce the discharge of PFCs from potential sources within the basin.

Chapter 2 Emission, Contamination and Exposure, Fate and Transport, and National Management Strategy of Persistent Organic Pollutants in South Korea

Abstract Public concern over persistent organic pollutants (POPs) re-emerged in the 1990s due to studies describing endocrine disrupting effects of some POPs. While monitoring data suggested that concentrations of contaminants were less in South Korea than in more industrialized countries, the public perception was that there were significant risks posed by POPs. This perception may have resulted from inaccurate and insufficient information about the status of POPs in South Korea. The South Korean government, as a signatory authority of the Stockholm Convention, is obliged to submit a national implementation plan to ban or minimize POPs emissions. To date, little has been known regarding the overall POPs status including inventories, usage patterns, sources, emission, fate, and distribution in South Korea. To assess the status of four emerging POPs as well as the 12 existing classical POPs in South Korea we have compiled and reviewed all the available literature published since the mid-1990s on POPs in South Korea. We present and discuss: (1) emission inventories of individual POPs; (2) concentrations of the various POPs in various compartments of the environment; (3) conducted ecosystem and human exposure assessments; (4) report a case study of fate and multi-media transport of POPs; and finally (5) propose an appropriate strategy to minimize the risks of POPs in South Korea. In brief, concentrations of POPs were found to be relatively small, compared to most other industrialized countries. In fact, concentrations of many of the classical POPs were less than the environmental quality criteria suggested by government agencies, except for a few ‘hot spots’. However, due to a lack of sufficient information, the status and trends of PCDDs/DFs, DDTs, PBDEs and PFAs could not be assessed. Additional information from monitoring studies would be needed for certain locations. For instance, the emission of dioxin-like compounds, expressed on a per area basis, was estimated to be one of the greatest in the world, even though the recent governmental efforts to reduce the emission have resulted in decreased releases of several classes of POPs. Concentrations of some perfluoroalkylated compounds (PFAs), in some freshwater locations were found to be some of the greatest in the world. Identification of hot spots followed by remediation (for classical POPs) and nationwide monitoring surveys (for emerging POPs) would be strongly needed.

Proximity of Field Distribution of Polycyclic Aromatic Hydrocarbons to Chemical Equilibria among Air, Water, Soil, and Sediment and Its Implications to the Coherence Criteria of Environmental Quality Objectives

The proximity of PAHs distribution to the equilibrium states among air, soil, water, and bottom sediment was assessed for future risk management and coherence test among environmental quality objectives (EQOs) in these media. Concurrently measured concentration data in the four media were used. In the study areas (Seoul, Shihwa/Banwol, and Taegu), nonequilibrium states prevailed among air, soil, and water except for some light PAHs between air and water. Elevated concentration in soil particularly caused significant deviation from equilibrium between soil and other media. Coherence criteria among these media should be determined based on steady state (not equilibrium) conditions. Sediment was in or near equilibrium with soil for all PAHs, indicating that sediment quality is closely related to soil quality and that the coherence between the EQOs of the two media is required in the study areas. As the concentration ratio of individual PAHs for a given medium pair was found to vary up to 4 orders of magnitude across the study areas, a factor of 10 as a threshold criterion for incoherence is apparently too strict to apply to the national scale of Korea.

Interrelationship of Pyrogenic Polycyclic Aromatic Hydrocarbon (PAH) Contamination in Different Environmental Media

Interrelationships between pyrogenic polycyclic aromatic hydrocarbons (PAHs) were assessed in air, soil, water, sediment, and tree leaves by using multi-media monitoring data. Concurrent concentration measurements were taken bimonthly for a year for the multi-media at urban and suburban sites. PAH level correlations between air and other media were observed at the urban site but were less clear at the suburban site. Considering a closer PAHs distribution/fate characteristics to soil than suspended solids, contamination in sediment seemed to be governed primarily by that in soil. The partitioning of PAHs in waters could be better accounted for by sorption onto black carbon and dissolved organic carbon.