• Journal of the Korean Data and Information Science Society
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• v.20 no.5
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• pp.955-960
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• 2009

As we shall dene an exponentiated complementary power function distribution, we shall consider moments, hazard rate, and inference for parameter in the distribution. And we shall consider an inference of the reliability and distributions for the quotient and the ratio in two independent exponentiated complementary power function random variables.

• Journal of Environmental Health Sciences
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• v.44 no.3
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• pp.227-237
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• 2018

Objectives: This study was investigated the characteristics of small-scale water works (SWW) in Gyeongnam area and conduct a health risk assessment of water-quality inspection items unfitted for water-quality standards (WQS). Methods: The characteristics of SWW in Gyeongnam province were analyzed using the data of SWW in the last three years (2014~2016) published in National Waterworks Information System. In addition, the health risk assessment for inspection items unfitted for WQS was carried out in four steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. Results: The total number of SWW in Gyeongnam area was gradually decreased from 2014 to 2016. In addition, drinking water sources of SWW were in the order of ground water, valley water, spring water, surface water, and river-bed water. The number of points unfitted for WQS in SWW by year was 22, 45, and 18 in 2014, 2015, and 2016, respectively, and a total of 112 points were found to unfit for WQS in SWW during 2014~2016. The hazard quotient (HQ) for fluoride, nitrate nitrogen, boron in the unfitted points for WQS was more than 1.0, and the mean values for turbidity and color in points unfitted for WQS were 2.38 nephelometric turbidity unit and 16.25 color unit, respectively. Conclusions: The HQ for fluorine, nitrate nitrogen and boron was more than 1.0 in points unfitted for WQS among SWW in Gyeongnam area, and the turbidity and the color degree exceeded WQS, which mean that there is a possibility of harmful impacts on the human health.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.155-155
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• 2017

• Journal of Environmental Science International
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• v.14 no.2
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• pp.121-128
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• 2005

Hexachlorobenzene (HCB) was analyzed in various marine organisms of Korea. HCB was detected in all organism samples with residual concentrations from 0.51 to 222 pg/g wet weight. HCB residue was the highest content in crustacean, and followed by bivalves, fish, cephalopods and gastropods. The residues were comparable to or lower than those in marine organisms of other countries. Daily dietary intake of HCB from seafood was estimated to be 13.4 pg/kg body weight/day. The relative contribution of taxonomic group to the total dietary intake of HCB were in the order of crustaceans $(40.1\%)$, bivalves $(34.2\%)$, fish $(23.1\%)$, cephalopods $(2.22\%)$, and gastropods $(0.38\%)$. Daily dietary intake of HCB expressed as toxic equivalent (TEQ) value was estimated to be $1.34\times10^{-3}pg$ TEQ/kg body weight/day. This value did not exceed tolerable daily intake (TDI) proposed by the WHO, the UK toxicity committee and the KFDA. Cancer risk and target hazard quotient (THQ) due to the consumption of the marine organism in Korean adult population were evaluated using the exposure equation of food ingestion. This result suggests that dietary intake of HCB by the consumption of Korean seafood seems to be safe for human health with negligible cancer and non-cancer risks so far.

• Journal of the Korean Data and Information Science Society
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• v.27 no.3
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• pp.577-586
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• 2016

Hazardous air pollution caused by heavy metals in the air is at a serious level. Although manganese(Mn), one of the heavy metals, is a non-carcinogenic substance, it has a harmful influence on the human body. It is partially measured because automatic monitoring technologies have not yet be fully established. We introduced a statistical model for the daily concentration of manganese. Incorporating a linkage between Mn and meteorology, the proposed model is formulated in way to identify meteorological effects and to allow for seasonal trends, enabling not only accurate measurement of manganese concentration, but also information about the evaluation on a Hazard Quotient (non-cancer risk).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.454-459
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• 2012

To investigate heavy metals (Hg, Pb and Cd) and their potential health risks in commercial dried laver (Porphyra sp.), we collected 45 samples from the major production areas on the western and southern coasts of Korea (Hwaseong, Seocheon, Gunsan, Muan, Shinan, Jindo, Haenam, Wando, Jangheung, Goheung and Busan). The Hg, Pb and Cd concentrations were measured using inductively coupled plasma spectrometry (ICP-MS) or a mercury analyzer. The average Hg, Pb and Cd concentrations in the dried laver were $0.006{\pm}0.0017$, $0.196{\pm}0.0614$ and $0.894{\pm}0.4882$ mg/kg, respectively. Based on the 2007 Korean Public Nutrition Report, these levels are 0.02, 0.11 and 2.47% of the provisional tolerable weekly intake (PTWI) for Hg, Pb and Cd, respectively, established by the FAO/WHO. The hazard quotient (HQ) determined from the ratio of exposure and safe levels were less than 1.0. Therefore, the levels of overall exposure to Hg, Pb and Cd for dried laver were below the recommended JECFA (Joint FAO/WHO Expert Committee on Food Additives) levels, which indicate safe levels for public health.

• Journal of Korean Society on Water Environment
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• v.20 no.5
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• pp.432-436
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• 2004

The principle and methodology of risk assessment was applied to establish the quality standard of potential impurities of drinking water treatment chemicals. The impurities(arsenic, lead, cadmium, chromium, mercury, etc.) are regulated as the contained quantity of chemicals in Korea while they are regulated as the quality standard with the idea of 10% of the national safety drinking water standard in U.S.A(NSF) and Japan(JWWA). According to risk assessment of the current standard implemented in Korea, the excess cancer risk of arsenic and lead were determined in around $10^{-5}$ and the hazard quotient(HQ) of cadmium and chromium were below $10^{-2}$, respectively. And the standard concentration of the impurities are regulated as much as 2%~6% of the national drinking water quality standard. The values are more enforced rather than the standards in U.S.A(NSF) and Japan(JWWA) regulating the concentration of impurities the 10% of the national drinking water quality standard. We conclude that the impurities standard of drinking water treatment chemicals should be reconsidered comprehensively concerning the national safety drinking water quality standard and risk assessment.

• Environmental Analysis Health and Toxicology
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• v.27
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• pp.5.1-5.10
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• 2012

Objectives: The purpose of this study was to assess the risk of ingestion exposure of lead by particle sizes of crumb rubber in artificial turf filling material with consideration of bioavailability. Methods: This study estimated the ingestion exposure by particle sizes (more than 250 um or less than 250 um) focusing on recyclable ethylene propylene diene monomer crumb rubber being used as artificial turf filling. Analysis on crumb rubber was conducted using body ingestion exposure estimate method in which total content test method, acid extraction method and digestion extraction method are reflected. Bioavailability which is a calibrating factor was reflected in ingestion exposure estimate method and applied in exposure assessment and risk assessment. Two methods using acid extraction and digestion extraction concentration were compared and evaluated. Results: As a result of the ingestion exposure of crumb rubber material, the average lead exposure amount to the digestion extraction result among crumb rubber was calculated to be $1.56{\times}10^{-4}$ mg/kg-day for low grade elementary school students and $4.87{\times}10^{-5}$ mg/kg-day for middle and high school students in 250 um or less particle size, and that to the acid extraction result was higher than the digestion extraction result. Results of digestion extraction and acid extraction showed that the hazard quotient was estimated by about over 2 times more in particle size of lower than 250 um than in higher than 250 um. There was a case of an elementary school student in which the hazard quotient exceeded 0.1. Conclusions: Results of this study confirm that the exposure of lead ingestion and risk level increases as the particle size of crumb rubber gets smaller.

• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.501-509
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• 2021

In 2018, total 263 micro and emerging contaminants were selected as target substances by the Ministry of Environment, and 80 of them were first-class substance including endocrine disruptors, residual Pharmaceuticals and Personal Care Products (PPCPs), residual organic pollutants, pesticides and heavy metals. In this study, in order to evaluate the Hazard Quotient (HQ) of the 80 types in the domestic water environment the concentration of discharged effluent and nearby water environment reported by Korean institutes since 2010 was investigated. There were 45 substances reported to be detected, and Measurement Environment Concentration (MEC) were obtained by collectively converting them into water environment concentration. For biotoxicity, half maximal Effective Dose (EC50) to Daphnia magna, a water fleas species widely adopted in Material Safety Data Sheet (MSDS) was applied. As for the biotoxicity level, the Predicted No-Effect Concentration (PNEC) was obtained by applying the Assessment Factor (AF) and the HQ was derived by dividing it from the MEC. As a result of calculating the HQ, more than 1 substances were Cabamazepine, Mefenamic acid, Acetaminophen, Ibuprofen, Nonylphenol, Nickel, Erythromycin, Acetylslic acid, etc. Meanwhile, perfluorinated compounds were identified as hazardous substances in the water env ironment, with 5 out of 14 species included in the 20 ranks of first-class substance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.836-843
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• 2022

In the present study, exposure to heavy metals by consumption of edible seaweeds (green laver, laver, hijiki, sea tangle, and sea mustard) was assessed based on their concentrations of lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg). The mean of heavy metal concentrations were 0.006-0.023 mg/kg for Pb, 0.037-0.156 mg/kg for Cd, 1.117-15.928 mg/kg for As, and 0.008-0.021 mg/kg for Hg. In multivariate analysis, the correlations were high between Pb levels in sea mustard, Cb levels in laver, and As and Hg level in Hijiki. However, the estimated daily intake and target hazard quotient (THQ) of the heavy metals in edible seaweeds were below their approved limits suggesting no health risks associated with seaweed consumption by Koreans.