• Analytical Science and Technology
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• v.23 no.6
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• pp.595-606
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• 2010

A total 221 samples of the retailed foods collected from 2004 to 2007 was examined to estimate the level of dioxins(29 congeners) by the isotopic dilution method, and the exposure of population of Korean to dietary of dioxins was performed. Dioxins levels were calculated using TEF values established in 1998 and 2005, respectively. The average levels (pg TEQ/g) were less than 0.01 for polished rice, 0.04 (poultry)-0.13 (beef) for meats, 0.04 (milk)-0.05(cheese) for milk and dairy products, 0.13 for egg (york, only) and 0.11 (alaska pollack)-1.35 (pacific mackerel) for fishes. The estimated daily intake of Korean through foods was 0.47 pg TEQ/kg bw/day, and it was estimated as about 11% to tolerable daily intake (TDI; 4 pg TEQ/kg bw/day) of Korea and Japan. Consequently, it was concluded that there was no health risk.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.7-15
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• 2012

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 $0.077{\mu}g/kg{\cdot}bw/day$ 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.

• Analytical Science and Technology
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• v.14 no.6
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• pp.504-509
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• 2001

The concentrations and TEQ levels of PCDFs/PCDDs in human aipose tissue and first breast milk were analyzed by high resolution gas chromatography/high resolution mass spectrometry. The human adipose tissue samples measured in this study have been collected at hospital in Seoul. The total concentration and TEQ level of PCDFs were showed 5.812 pg/g and 1.485 pgTEQ/g. The total concentration and TEQ level of PCDDs were showed 26.648 pg/g and 1.176 pgTEQ/g, respectively. This paper also reported dioxin levels in 20 breast milks of Korean mothers from hospital in Seoul National University. Total concentration and TEQ levels of PCDFs were showed 7.019 pg/mL and 0.177 pgTEQ/mL, respectively. Total concentrations and TEQ levels of PCDDs were showed 14.224 pg/mL and 0.693 pgTEQ/mL, respectively. According to the contribution of dioxin congeners in samples, PCDDs was higher than PCDFs. And OCDD had the highest concentration.

• Applied Biological Chemistry
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• v.18 no.3
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• pp.145-166
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• 1975

The calcium balance study was carried out to determine the availability of calcium in different sources for chicks and laying hens. The sources of calcium were calcium carbonate (CC), dicalcium phosphate-dihydrate (DCPH), and dicalcium phosphate-anhydride (DCPA) for chicks and calcium carbonate (CC) and oyster shell (OS) for laying hens. The radioisotope dilution method was employed to measure the endogenous excreta calcium during the period of balance study following preliminary feeding. A. Experimental results with chicks: No significant difference was found among feed consumption of chicks fed diets containing different sources of calcium. Body weight gain of chicks was dependent upon the source of calcium. The gain decreased in the order of DCPH, DCPA and CC (P<0.01). The feed conversion efficiency in chicks fed DCPH was better than those in chicks fed CC or DCPA. The average tibia ash contents for chicks fed different sources of calcium were similar. The DCPH was superior to CC or DCPA regarding the calcium content in tibia ash. There were no significant differences among the average calcium contents in plasma trichloracetic acid filtrate in chicks irrespective of calcium sources. The mean apparent retention of calcium by chicks fed DCPH, CC and DCPA were 65.9, 64.0 and 59.9% respectively. The calcium to phosphorus ratios in tibia ash and plasma trichloracetic acid filtrate for chicks fed different sources of calcium were similar. The chicks fed DCPH showed the partition of endogenous excreta calcium in total excreta calcium as 35.6% which was higher than 31.0 or 31.4% for chicks fed CC or DCPA. The endogenous excreta calcium per day per chick in group fed DCPH, DCPA or CC were 17.2, 16.1 and 14.6mg respectively. The true retained calcium per day per chick in group fed DCPH were 109.9 mg which was higher than those observed with CC or DCPA group (P<0.01). The true retention of calcium by the birds fed diets containing DCPH, CC or DCPA were 78.1, 75.1 or 72.6% respectively. B. Experimental results with laying hens: The feed consumption, egg production and feed converion efficiency of laying hens fed diets containing different sources of calcium were similar. Calcium concentration in plasma trichloracetic acid filtrate in laying birds fed CC was equivalent to the value obtained by feeding OS. The apparent calcium retention by laying birds fed CC was 61.6% and it was significantly more than that of hens fed OS of 51.6% (P<0.05). The partition of endogenous excreta calcium in total excreta calcium of laying hens fed CC was 23.5% and this was higher than that of birds fed OS of 15.6%. The laying hens fed CC showed 310 mg of endogenous excreta calcium per day per bird while birds fed OS showed 261mg. The true retention of calcium by layers fed CC was 70.7% against 59.2% for birds fed OS (P<0.05).