Sung-Ug We

Spatial distribution of polybrominated diphenyl ethers and hexabromocyclododecanes in sediments from coastal waters of Korea

Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) were determined in surface sediments collected from 24 coastal locations in Korea. The concentrations of summation operatorPBDEs (defined as the sum of all targeted PBDE congeners except for BDE-209) and BDE-209 ranged from 0.05 to 32 ng g(-1) dry wt. and from 0.40 to 98 ng g(-1) dry wt., respectively. The PBDE congener compositions were dominated by BDE-209, which is in accordance with the consumption of decaBDE mixture in Korea. HBCD concentrations ranged from 0.39 to 59 ng g(-1) dry wt. Concentrations of PBDEs and HBCDs were found to be higher near locations with industrial complexes and harbors, associating these compounds to urbanization and industrialization. Significant positive correlations between PBDE and HBCD concentrations and organic carbon content in sediments imply the role played by organic matter in the contaminant transport and trapping in the aquatic environment.

The Relationship among the Indicator PCBs in Breast Milk and Dietary Habits and Demographic Factors in Women Living in Urban Areas

In this study, breast milk levels of indicator polychlorinated biphenyls (PCBs) were estimated, and statistics drawn, for 22 Koreans in the general population, aged 26-38, who had resided in metropolitan areas for more than 5 years without occupational exposure to organochlorine pollutants. Concentrations of indicator PCBs were measured using the isotope dilution method with a high resolution gas chromatograph/high resolution mass detector, which provided accurate and precise data for investigation of trends, and international comparisons. The geometric mean of total indicator PCB levels was 22.3 ng/g lipid, which is significantly lower than the level in individuals from European countries. Overall, the geometric mean and 95th percentile of the most abundant congener PCB 153 were 8.04 ng/g lipid and 16.4 ng/g lipid, respectively. PCB congeners 138, 153 and 180 together accounted for about 75% of the indicator congeners analyzed. Breast milk total indicator PCB concentrations were significantly associated with age and parity, but not with body mass index (BMI), rate of body weight increase, or smoking habits. The geometric mean level of PCB 153 in breast milk from mothers with a pre-pregnant BMI <21 kg/m was significantly higher than in pre-pregnant women with a BMI of 21 kg/m (p<0.05). Women who ate more fish, meat, and milk products did not have significantly higher total indicator PCB levels than those who ate less of these products, but a significant difference in PCB 153 levels was demonstrated between the subjects consuming higher (11.45 ng/g lipid) and lower (6.79 ng/g lipid) amounts of fish (p<0.05), after adjusting for confounders. These results suggest that age, parity and fish intake are the important factors affecting the concentrations of indicator PCBs in these subjects.

Human Risk Assessment of Polybrominated Diphenyl Ethers by Breast Milk Feeding of Infants

This study achieves results from 22 maternity breast milk samples in total to demonstrate exposure level and risk assessment of PBDEs in Seoul area. PBDEs were detected in all the breast milk samples of the present study, indicating that general population in these Seoul area are widely exposed to these chemicals. Residue levels of total PBDEs (sum PBDEs from trito hepta-BDE) ranged of 0.84~13.1 ng/g lipid with an arithmetic mean and median of 3.56 ng/g lipid and 2.6 ng/g lipid, respectively. Global comparison shows that the levels of total PBDEs were relatively similar to those of China, Taiwan and European country (Sweden), and somewhat higher than those in some Asian (Vietnam, Philippines, and Indonesia). In the present study, however, the levels of total PBDEs in human milk are still one to two orders of magnitude lower than those in North America. Contribution rate of each congener appeared to be predominant with BDE-47, followed by BDE-153, BDE-100, BDE-99, BDE-154 and BDE-183. The sum of BDE-47 and BDE-153 accounted for more than 65% of total PBDEs in most samples. From the result of the human risk assessment of infants for total PBDEs and BDE-47 by breast milk feeding, we could find out that the average daily doses and hazard index (95th percentile) were 16.5 ng/kg.bw/day and 1.2 × 10 each other when nursing for 6 months after infants born. However, it was concluded that the infant health hardly had adverse seriously effects under this research condition.

Estimation of Indicator PCBs Exposure in Infants via Breast-Feeding Period

The levels of indicator PCBs were determined in 132 human milk samples (Colostrum, 30th days after delivery, 60th days after delivery) collected in 2006 according to World Health Organization’s (WHO) protocol. In addition, concentrations of indicator polychlorinated biphenyls (PCBs) were measured by the isotope dilution method with high resolution gas chromatograph/ high resolution mass detector (HRGC/HRMS), which gave accurate and precise data for estimations of international trend and comparisons. Average daily intakes (ADIs) of all analytes were calculated. The median level of total indicator PCBs was 14 ng/g lipid, which is significantly lower than the level found in individuals from other countries. PCB congeners 138, 153 and 180 accounted for about 65% of the sum of the indicator congeners analyzed. The concentration of the most abundant PCB 153 is positively correlated with the concentration of the sum indicator PCBs (p < 0.001). In this study, concentrations of total indicator PCBs significantly decreased with increasing number of children for a mother, indicating that parity and breast-feeding period an important role in the accumulation and elimination of these compounds in lactating women. The ADI for the median of total indicator PCBs for an infant was evaluated at 0.077 μg/kg·bw/day from birth to 6 months of age. The present study shows that concentrations of PCB 118 primipara breast milk have decreased 25~35 since 1998, and that this trend is continuing.

Concentrations of PBDE Congeners in Breast Milk and Predictors of Exposure in Seoul Residents

Objectives: This study was designed to determine the levels of polybrominated diphenyl ethers (PBDEs) in breast milk and to evaluate the relations with factors affecting these levels. Methods: The congener levels of PBDE in 22 samples of breast milk were analyzed using a high resolution gas chromatograph with a high resolution mass detector. In accordance with our standard operating procedures, the recoveries of internal standards had to range between 68% and 118%. Since the distribution of PBDE concentrations is close to log-normal, the data were logarithmically transformed before analysis. Test subjects were healthy primipara and multipara mothers with a mean age of 32 (SD = 2.7) in 2006. Results: Seven PBDE congeners (BDE-28, 47, 99, 100, 153, 154, and 183) were detected and identified in all of the pooled breast milk samples, indicating widespread contamination from PBDEs in the environment in Korea. Residue levels of total PBDEs (sum PBDEs from tri- to hepta-BDE) ranged from 0.84-13.1 ng/g lipid with median and geometric mean levels of 2.6 ng/g lipid and 2.74 ng/g lipid, respectively. PBDE congeners 47, 99 and 153 markedly predominated and accounted for about 75% of the amount of the PBDE congeners analyzed. BDE-47 was the dominant congener in most samples, whereas BDE-153 was predominant in a few (n = 7/22). BDE-47 was highly correlated with total PBDEs (r = 0.987, p

Residual Consistency and Interrelationship Estimation of PCDDs, PCDFs, Dioxin-like PCBs in Colostrum of Primipara and Multipara

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) are bioaccumulative chemicals that are considered to be toxic contaminants based on several epidemiological studies. These chemicals in colostrum were investigated and estimated for their residual consistencies by maternal characteristics like parity and maternal ages. Test subjects were healthy primipara and multipara mothers with a mean age of 31.5 (S.D