• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.220-227
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• 2005

The estrogenic phenolic compounds, nonylphenol (NP), octylphenol(OP), bisphenol A (BPA) and nonylphenol mono- and diethoxylate ($NP_{1-2}EO$) were analyzed in 24 surface water samples from six rivers flowing into Masan Bay. All of the phenolic compounds were detected in all six rivers in high concentrations. The most abundant compound was $NP_{1-2}EO$ (86.0%), followed by NP ($10.1 \%$), BPA ($3.6\%$) and OP ($0.3\%$). The levels of phenolic compounds were 1.42-22.70 ${\mu}g$/L for $NP_{1-2}EO$, 0.15-1.68 ${\mu}g$/L for NP, 0.024-0.610 ${\mu}g$/L for BPA and 0.003-0.067 ${\mu}g$/L for OP. Especially, high concentrations were recorded in the rivers that pass through industrial complexes. The concentrations of phenolic compounds observed in these river waters were 1-2 orders of magnitude lower than the reported acute toxicity levels (hundreds of micrograms per liter). However, they were only slightly lower than the chronic toxicity levels. Most of the water samples also exceeded the Canadian nonylphenolic compounds water quality guideline, 1 ${\mu}g$/L, for the protection of aquatic life and the maximum permissible concentrations (MPC), 0.33 ${\mu}g$/L for NP and 0.12 ${\mu}g$/L for $NP_{1-2}EO$.

• Journal of the Korean Chemical Society
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• v.13 no.2
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• pp.181-186
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• 1969

The concentration of Strontium-90 in liquid whole milk produced in Korea were measured during past four years. The samples of milk were purchased from dairies in Seoul. Strontium-90 was analysed radiochemically and the amount of stable calcium was also determined. Radioactivity of Yttrium-90 was counted in low background beta counter which has the background of 1.38 cpm. The concentrations of Strontium-90 in the milk are 25.1 PCi $^{90}Sr$/g.Ca in 1965, 26.8 PCi $^{90}Sr$/g. Ca in 1966, 13.7 PCi 90Sr/g.Ca in 1967 and 18.2 PCi $^{90}Sr$/g.Ca in 1968 in annual average. The concentrations of Strontium-90 in the milk of 1967 and of 1968 were decreased approximately compared with the values of 60% 1965 and 1966. From the results we can see that Strontium-90 concentrations in the milk vary roughly proportionally with the specific activity of fallout. Considering on the safety problems, the Strontium-90 levels in the milk produced in Korea were far below the maximum permissible level recommended by ICRP.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.23-27
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• 1988

In order to investigate the combined effect of potassium sorbate and sodium benzoate and the synergistic effect of sodium chloride on bacterial cell growth inhibition, Bacillus subtilis was cultured with or without shaking in tryptone-glucose-yeast extract broth containing 0.1% potassium sorbate and/or 0.03% sodium benzoat, which are equivalent to half of the maximum permissible levels, respectively. The combined treatment of the two preservatives did not show any synergistic effect of tne growth inhibition of B. subtilis. Addition of 2% sodium chloride, however, showed remarkable synergistic effect on the growth inhibition of the bacterium by potassium sorbate.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.1
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• pp.32-40
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• 2008

Methyl bromide has been used as a representative fumigant for quarantine, and several poisoning cases have occurred recently by this chemical in Korea. The purpose of this study is to evaluate workers' exposures to airborne methyl bromide in the importing and exporting plant products quarantine companies. Air samples were collected 400/200 mg Anasorb 747TM and were analyzed by gas chromatograph /flame ionization detector according to the Occupational Safety and Health Agency (OSHA) Method PV2040. Geometric mean (GM) and arithmetic mean (AM) of total 27 workers' exposure concentrations to airborne methyl bromide were 1.12 ppm and 0.24 ppm, respectively. Two exposures(12.1 ppm and 12 ppm as 8hr-TWA) of total 27 workers' exposures exceeded the Korean standard (5 ppm) of Ministry Labor, while 4 exposures (15%) exceeded the Threshold Limit Value (TLV) (1 ppm) of American Conference of Governmental Industrial Hygienists (ACGIH). Seven samples (11%) of total 63 short-term air samples exceeded the OSHA Permissible Exposure Limit (PEL) 20 ppm (Ceiling). The opening (management) task in wood fumigation by tent showed the highest short-term exposure concentrations (AM: 18.6 ppm, GM: 0.58 ppm, maximum: 340.7 ppm). The maximum level in treatment task of the same process was 2.01 ppm. Methyl bromide concentrations in opening operation was significantly higher than that in treatment operation (p<0.05). In conclusion, the GM of workers' 8hr-TWA exposures to airborne methyl chloride in the importing/exporting plant quarantine industry was estimated below the ACGIH TLV (1 ppm). However, opening task in the fumigation of wood being covered with tent or fumigation of pant products in container showed the levels exceeding ACGIH TLV (1 ppm), and opening task in the fumigation of wood being covered with tent showed the level exceeding the Korean standard of Ministry of Labor (5 ppm).

• Advances in concrete construction
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• v.3 no.4
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• pp.253-268
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• 2015

This paper investigates the influence of various mix design parameters on the characteristics of concrete containing recycled coarse aggregates and Nano-Silica using Taguchi method. The present study adopts Water-cement ratio, Recycled Coarse Aggregate (%), Maximum cement content and Nano-Silica (%) as factors with each one having three different levels. Using the above mentioned control parameters with levels an Orthogonal Array (OA) matrix experiments of L9 (34) has selected and nine number of concrete mixes has been prepared. Compressive Strength, Split Tensile Strength, Flexural Tensile Strength, Modulus of Elasticity and Non-Destructive parameters are selected as responses. Experimental results are analyzed and the optimum level for each response is predicted. Analysis of 28 days CS depicts that NS (%) is the most significant factor among all factors. Analysis of the tensile strength results indicates that the effect of control factor W/C ratio is ranked one and then NS (%) is ranked two which suggests that W/C ratio and NS (%) have more influence as compared to other two factors. However, the factor that affects the modulus of elasticity most is found to be RCA (%). Finally, validation experiments have been carried out with the optimal mixture of concrete with Nano-Silica for the desired engineering properties of recycled aggregate concrete. Moreover, the comparative study of the predicted and experimental results concludes that errors between both experimental and predicted values are within the permissible limits. This present study highlights the application of Taguchi method as an efficient tool in determining the effects of constituent materials in mix proportioning of concrete.

• The Korean Journal of Nuclear Medicine
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• v.37 no.2
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• pp.110-119
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• 2003

Purpose: Radioiodine (I-131) therapy is an effective modality to reduce both recurrence and mortality rates in differentiated thyroid cancer. Whether higher doses shows higher therapeutic responses was still debatable. The purpose of this study was to validate curve-fitting (CF) method measuring maximum permissible dose (MPD) by a biological dosimetry using metaphase analysis of peripheral blood lymphocytes. Materials and Methods: Therapeutic effects of MPD was evaluated in 58 patients (49 females and 9 males, mean age $50{\pm}11$ years) of papillary thyroid cancer. Among them 43 patients were treated with ${\Leq}7.4GBq$, while 15 patients with ${\geq}9.25GBq$. The former was defined as low-dose group, and the latter high-dose group. Therapeutic response was defined as complete response when complete disappearance of lesions on follow-up I-131 scan and undetectable serum thyroglobulin levels were found. Statistical comparison between groups were done using chi-square test. P value less than 0.05 was regarded as statistically significant. Results: MPD measured by CF method using tracer and therapeutic doses were $13.3{\pm}1.9\;and\;13.8{\pm}2.1GBq$, respectively (p=0.20). They showed a significant correlation (r=0.8, p<0.0001). Exposed doses to blood measured by CF and biological methods were $1.54{\pm}0.03\;and\;1.78{\pm}0.03Gy$ (p=0.01). They also showed a significant correlation (r=0.86, p=0.01). High-dose group showed a significantly higher rate of complete response (12/15, 80%) as compared to the low-dose group (22/43, 51.2%) (p=0.05). While occurrence of side effects was not different between two groups (40% vs. 30.2%, p=0.46). Conclusion: Measurement of MPD using CF method is reliable, and the high-dose I-131 therapy using MPD gains significantly higher therapeutic effects as compared with low-dose therapy.

• Economic and Environmental Geology
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• v.30 no.6
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• pp.587-601
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• 1997

This study had three purposes: (1) to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock-soil-plant system; (2) to evaluate the uptake ratios of heavy metals from soils into plants and (3) to assess the chemical speciation of heavy metals in soils. Rock, surface soil and plant samples were collected in the Boeun area underlain by black shales of the Okchon Zone. These samples were analyzed for multi-elements using INAA, ICP-AES and AAS. The maximum abundance of U in black shales is 16 mg/kg and radioactivity counts up to 300 cpm. In particular, Mo, V, Ba, Cd, Pb and U are enriched in black shales. Most of soils derived from black shales show high concentrations of U, As, Mo, Ba, Cu, Cd, Pb, Zn and mean concentrations of As and Mo in soils (20 mg/kg of As and 6.6 mg/kg of Mo) are higher than the permissible level suggested by Kloke (1979). Enrichment index values of soils are calculated and higher than 1.0 in the black shale area with the highest value of 6.4. Mean concentration of Cd in plants is higher than those of Cu, Pb and Zn. The concentration of Cd in plant species decreases in the order of Chinese cabbage > red pepper > soybean=sesame > rice stalk > com > rice grain. The biological absorption coefficients (BAC) in plants are in the order of Cd > Zn=Cu > Pb, which suggests that Cd is more bioavailable to plants than Cu, Pb and Zn. From the results of sequential extraction analysis of soils, relatively high proportion of Cu, Pb and Zn are present as residual fractions whereas that of Cd as non-residual fractions. Cadmuim occurs predominantly as exchangeable/water-acid soluble phase in soils, and Cd is more mobile and bioavailable than Cu, Pb and Zn.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.492-497
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• 2005

In establishing legal limits of pesticide residues, various default values are employed to compensate for unavoidable variability in data. Because permissible errors in residue analysis reach ${\pm}30-40%$ RSD, maximum residue limits (MRLs) follow geometric progression. According to 5-yr period JMPR reports, variability factor (ratio of highest to median values) in field residue trials was 3.8-fold in 486 crop-pesticide combinations and round-up effort from highest residue to MRL was 1.5-fold, whereas regulatory margin (ratio of MRL to highest residue) used in Korea was 4.8-fold in 822 crop-pesticide combinations; Korean MRLs will be set at higher levels as compared with Codex limits if these margins are employed. Validation studies to compare and harmonize Korean and Codex MRLs of pesticide residues on food crops should be undertaken.

• Food Science of Animal Resources
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• v.37 no.1
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• pp.79-86
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• 2017

Aflatoxin $M_1$ ($AFM_1$) after its bioconversion from aflatoxin $B_1$ in animal liver becomes the part of milk while heavy metals get entry into milk and milk products during handling in the supply chain. Aflatoxin $M_1$ and heavy metals being toxic compounds are needed to be monitored continuously to avoid any ailments among consumers of foods contaminated with such toxicants. Thirteen commercially available infant formula milk (IFM) brands available in Pakistani markets were analyzed for the quantitative determination of $AFM_1$ and heavy metals through ELISA and atomic absorption spectrophotometer, respectively. $AFM_1$ was found positive in 53.84% samples while 30.76% samples were found exceeding the maximum EU limit i.e. $0.025 {\mu}g/kg$ for $AFM_1$ in IFM. Heavy metals lead (Pb) and cadmium (Cd) were found below the detection limits in any of the sample, whereas the concentrations of iron (Fe), zinc (Zn) and nickel (Ni) ranged between 45.40-97.10, 29.72-113.50 and <$0.001-50.90 {\mu}g/kg$, respectively. The concentration of Fe in all the tested brands was found in normal ranges while the concentrations of Zn and Ni were found exceeding the standard norms. Elevated levels of $AFM_1$, Zn and Ni in some of the tested IFM brands indicated that a diet completely based on these IFM brands might pose sever health implications in the most vulnerable community i.e., infants.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.1
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• pp.10-18
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• 2010

To provide necessary information for future environmental monitoring of smelting and litharge making industries in Korea, environmental monitoring dataset of air lead concentration of 4 lead industries(1 primary smelting, 2 secondary smelting and 1 litharge making industry) were analyzed from 1994 to 2007. Data were compared using geometric mean and standard deviation with minimum and maximum values according to year of measurement, type of lead industries and type of operation of lead industries. The geometric mean and standard deviation of air concentration for a total of 1140 samples in all lead industries for overall 14 years were 70.7${\mu}g/m^3$ and 5.51 with minimum of 1${\mu}g/m^3$ and maximum of 9,185 ${\mu}g/m^3$. The overall geometric means of air concentration were above the permissible exposure levels(PEL) until year of 2001 and thereafter they were remained at the level of half of PEL. The geometric means of primary smelting, secondary smelting and litharge making industry for overall 14 years were 21.7${\mu}g/m^3$(number of samples: 353), 82.5${\mu}g/m^3$(number of samples: 357) and 164.2 ${\mu}g/m^3$(number of samples: 430) respectively. In primary smelting industry, the highest geometric mean air concentration was 35.4 ${\mu}g/m^3$ in the secondary smelting operation; followed by casting operation (24.9 ${\mu}g/m^3$) and melting operation (14.9 ${\mu}g/m^3$), respectively. On the other hand, in secondary smelting industries, the highest geometric mean air concentration was 125.4${\mu}g/m^3$ in melting operation; followed by casting operation (90.5${\mu}g/m^3$) and pre-treatment operation (43.4${\mu}g/m^3$), respectively. However, in litharge making industries, there were no significant differences of geometric mean air concentrations between litharge operation and stabilizer operation. The proportion of over PEL (50${\mu}g/m^3$) was highest in litharge industry and followed by secondary smelting industries. However The proportions of over PEL(${\mu}g./m^3.$) were decreased by the years of environmental monitoring. The significant reduction of mean air lead concentration since year of 2000 was observed due to more active environmental engineering control and new introduction of new operation in manufacturing process, but may be also influenced by non-engineering method such as reduction of operation hours or reduction of exposure time during actual environmental measurement by industrial hygienist according to more strict enforcement of occupational and safety law by the government.