• Journal of the Korean Recycled Construction Resources Institute
• /
• v.8 no.4
• /
• pp.483-489
• /
• 2020

Particulate matter is divided into PM10 (particle diameter of 10 ㎛ or less) and PM2.5 (particle diameter of 2.5 ㎛ or less), which are approximately 1/5 of the thickness of the hair. Due to its effect on the human body, lung disease, arteriosclerosis and heart It is known as a carcinogen that causes various diseases such as diseases. It is known that the main cause of such fine dust is nitrogen dioxide (NOx), which is emitted from automobiles in about 57.3% of urban roadsides. Therefore, in this study, as part of the development of functional construction materials to reduce NOx generated from road transport pollutants, comparative evaluation of NOx reduction performance was conducted according to the replacement rate of cement mortar in which cement was replaced with a porous material. In addition, the NOx reduction performance of cement mortar according to the photocatalyst application method and the number of applications was compared an d evaluated. As a result of the experiment, when activated ocher was substituted by 30%, it showed a reduction effect of about 32.7%, showing the best reduction performance.

• Analytical Science and Technology
• /
• v.22 no.5
• /
• pp.386-394
• /
• 2009

Formaldehyde is used in lether manufacture, a dry plate and an explosive. It is by-product of ozonizing process in filtration plant. The effects of exposure are eye pruritus, tickle, runing nose, blocking nasal passages and headache. It also makes a dried throat and causes inflammation. It is classified as B1 group for inhalation by US. EPA, which can cause cancer in human. For analysis of formaldehyde, formaldehydes-DNPH derivative was extracted with solid cartridge and was analyzed by High Performance Liquid Chromatography/Diode Array Detector (HPLC/DAD). The detection limit was $3{\mu}g/L$ and the recoveries were 72.3~109.1% (RSD 2.9~11.5%). Water samples were collected in four Korean rivers, four times per year seasonally for 10 years from 1998 to 2007. The monitoring results were 48.8% (630/1291), $5.15{\sim}101.9{\mu}g/L$ in purified water. Because of non-carcinogen in drinking water, hazard index is calculated with RfD. Results of excess cnacer risk was below 1 and was considered as safe value.

• Journal of Korea Soil Environment Society
• /
• v.3 no.2
• /
• pp.13-29
• /
• 1998

Recently, It is increasing popularity to research on the soil remediation in aspect of management by reason of the hazardous impact on the contaminated soil in Korea. It was investigated high levels of arsenic salts in soil near abandoned five mines(Darak, Daduk, Jingok, Dalsung, Ilkwang) located in Youngnam area. Arsenic, classified as group A(Human Carcinogens) from IRIS, have shown statistically significant increment in skin cancer with oral exposure. This paper was conducted to predict excess cancer risk value (to the skin cancer) based on multiple pathway such as soil ingestion, dermal uptake and food(plant) ingestion contaminated by arsenic, and also, to identify the remedial goal regarded in future land use. The mine having the highest arsenic level was Daduk(mean : 1950mg/kg) and the next rank was Jingok(1690mg/kg), Ilkwang(352.37mg/kg), Dalsung(86.08mg/kg), Darak(0.83mg/kg). The chronic daily intake to the multiple exposure were calculated using Monte-Carlo simulation regarded in future land use and used q: value was $1.5(mg/kg/day)^{-1}$ to the oral proposed by IRIS(1997). The computated excess cancer risk 95th value to all the mine regarding future land use as residential and rural area were more than $10^{-4}$. If the level of acceptable risk is aimed for 1$\times$$10^{-6}$, it could be used Darak as commercial and industrial area without soil remediation due to the lowest risk value(6$\times$$10^{-8}$ and 3$\times$$10^{-8}$). Computated remedial goal based on 1$\times$$10^{-6}$ of acceptable risk to the future land use as the residential, rural, commercial and industrial area were 0.02mg/kg, 0.003mg/kg, 97.31mg/kg and 194.62mg/kg, respectively.

• Analytical Science and Technology
• /
• v.16 no.4
• /
• pp.299-308
• /
• 2003

The purpose of this study is to investigate cadmium concentrations among metals in ETS (Environmental Tobacco Smoke) of indoor environments and to evaluate the cadmium as a marker of ETS. The correlations of cadmium concentrations and nicotine, 3-EP, RSP, SD (Smoking Density), and SI (Smoking Index). Air samples of metals, nicotine, 3-EP, and RSP were taken in smoking room, smoking allowed office, corridor outside smoking room, and non-smoking office respectively. The SD, ACH, and SI were investigated during sampling. Airborne concentration of cadmium known as human carcinogen were qualified and quantified. The SD was 0.2 to $2.6cig/m^2{\cdot}hr$, and the mean value of SD in smoking rooms was $1.2cig/m^2{\cdot}hr$ that is higher than other researches. The mean of ACH in smoking rooms was 11.1. The concentrations of cadmium showed log-normal distributions and the geometric mean concentrations of cadmium in smoking rooms, corridor outside smoking rooms, smoking allowed offices, and non-smoking offices were $0.045{\mu}g/m^3$, $0.018{\mu}g/m^3$, $0.021{\mu}g/m^3$, and $0.017{\mu}g/m^3$ respectively. The concentrations of cadmium in smoking room showed significant difference according to category of indoor office environments (p<0.05) and showed compliance with occupational exposure limits. The correlation coefficients between cadmium and nicotine, 3-EP, and RSP were 0.53, 0.41, 0.43 respectively. The cadmium among metals showed the highest correlations (r=0.63) with SI. It was recommended cadmium among metals is a good indicator for ETS.

• Economic and Environmental Geology
• /
• v.52 no.6
• /
• pp.627-635
• /
• 2019

Cement-asbestos slate is the main asbestos containing material. It is a product made by combining 10~20% of asbestos and cement components. Man- and weathering-induced degradation of the cement-asbestos slates makes them a source of dispersion of asbestos fibres and represents a priority cause of concern. When the asbestos enters the human body, it causes cellular damage or deformation, and is not discharged well in vitro, and has been proven to cause diseases such as lung cancer, asbestos, malignant mesothelioma and pleural thickening. The International Agency for Research on Cancer (IARC) has designated asbestos as a group 1 carcinogen. Currently, most of these slats are disposed in a designated landfill, but the landfill capacity is approaching its limit, and there is a potential risk of exposure to the external environment even if it is land-filled. Therefore, this study aimed to exam the possibility of detoxification of asbestos-containing slate by using exothermic reaction and heat treatment. Cement-asbestos slate from the asbestos removal site was used for this experiment. Exothermic catalysts such as calcium chloride(CaCl₂), magnesium chloride(MgCl₂), sodium hydroxide(NaOH), sodium silicate(Na₂SiO₃), kaolin[Al₂Si₂O₅(OH)₄)], and talc[Mg₃Si₄O₁₀(OH)₂] were used. Six catalysts were applied to the cement-asbestos slate, respectively and then analyzed using TG-DTA. Based on the TG-DTA results, the heat treatment temperature for cement-asbestos slate transformation was determined at 750℃. XRD, SEM-EDS and TEM-EDS analyses were performed on the samples after the six catalysts applied to the slate and heat-treated at 750℃ for 2 hours. It was confirmed that chrysotile[Mg₃Si₂O₅(OH₅)] in the cement-asbestos slate was transformed into forsterite (Mg₂SiO₄) by catalysts and heat treatment. In addition, the change in the shape of minerals was observed by applying a physical force to the slate and the heat treated slate after coating catalysts. As a result, the chrysotile in the cement-asbestos slate maintained fibrous form, but the cement-asbestos slate after heat treatment of applying catalyst was broken into non-fibrous form. Therefore, this study shows the possibility to safely verify the complete transformation of asbestos minerals in this catalyst- and temperature-induced process.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.7
• /
• pp.839-845
• /
• 2009

Colorectal cancer is the third most common malignant neoplasm in the world. Much attention has been focused on reducing colon cancer risk through medical properties of natural compound that could act as anticarcinogens. In this study, we evaluated the antioxidant and antigenotoxic effects of Styela plicata (S. plicata) from in vitro experiments. S. plicata extracts showed antioxidant activity measured by TRAP assay and antigenotoxic effect in $200{\mu}M$ $H_2O_2$ induced DNA damage in human leukocytes. Especially, freeze-dried S. plicata extracted with methanol showed the highest level of TRAP (0.225 mM) and inhibition of DNA damage (66.8%). Additionally we observed the effect of S. plicata on the formation of aberrant crypt foci (ACF) induced by dimethylhydrazine (DMH) and DMH induced DNA damage (by comet assay) in male SD rats. The animals were divided into three groups and fed high-fat and low fiber diet (100 g lard+20 g cellulose/kg diet) without (normal control and DMH control) or with a 3% (w/w) of lyophilized S. plicata powder (DMH+S. plicata). One week after beginning the diets, rats were treated with DMH (30 mg/kg, s.c.) for 6 weeks except for normal control group, which was treated saline instead; dietary treatments were continued for the entire experiment. Nine weeks after DMH injection, administration of S. plicata resulted in reduction of ACF numbers, to 82.7% of the carcinogen control value ($7.67{\pm}2.04$ vs. $1.33{\pm}0.53$: p<0.01). S. plicata supplementation induced antigenotoxic effect on DMH-induced DNA damage in the blood cell (% tail intensity: $6.79{\pm}0.26$ vs. $6.13{\pm}0.22$). These data indicate that S. plicata extract has antigenotoxic and anticarcinogenic effects from in vitro experiments and S. plicata exerts a protective effect on the process of colon carcinogenesis, possibly by suppressing the DMH-induced DNA damage in blood cell and the development of preneoplastic lesions in colon.

• Journal of Environmental Health Sciences
• /
• v.37 no.6
• /
• pp.429-439
• /
• 2011

Objectives: Ethylene oxide (EtO) is classified as a human carcinogen, but EtO is still widely used to sterilize heat-sensitive materials in hospitals. Employees working around sterilizers are exposed to EtO after sterilization. The aim of the present study was to assess the exposure of EtO level, coupled with occupationally induced micronuclei from hospital workers. The influence of genetic polymorphisms of detoxifying genes (GSTT1 and GSTM1) and DNA repair genes (XRCC1 and XRCC3) on the frequencies of micronuclei in relation to exposure of EtO was also investigated. Methods: The study population was composed of 35 occupationally exposed workers to EtO, 18 student controls and 44 unexposed hospital controls in Korea. Exposure to EtO is measured by passive personal samplers. We analyzed the frequencies of micronuclei by performing cytokinesis-block micronucleus assay (CBMN assay) and GSTM1, GSTT1, XRCC1, and XRCC3 were also genotyped by performing polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: The frequencies of micronuclei in EtO exposure group, student controls and hospital controls were $18.00{\pm}7.73$, $10.47{\pm}7.96$ and $13.86{\pm}6.35$ respectively and their differences were statistically significant, but no significant differences according to the level of EtO were observed. There was a dose-response relationship between the frequencies of micronuclei and cumulative dose of EtO, but no significantly differences were observed. We also investigated the influence of genetic polymorphisms (GSTM1, GSTT1, XRCC1, and XRCC3) on the frequencies of micronuclei, but there were no differences in the frequencies of micronuclei by genetic polymorphisms. Conclusions: The frequencies of micronuclei in EtO exposure group was significantly higher than control groups. A dose-response relationship was found between the level of EtO exposure and the frequencies of micronuclei, but no statistically differences were observed. We also found that the frequencies of micronuclei were increased according to cumulative EtO level. There was no association of the genetic GSTM1, GSTT1, XRCC1, and XRCC3 state with the frequency of micronuclei induced by EtO exposure.

• Journal of Soil and Groundwater Environment
• /
• v.11 no.6
• /
• pp.69-75
• /
• 2006

Improper disposal of petroleum and spills from underground storage tanks have created large areas with highly toxic contamination of the soil and groundwater. Methyl tert-butyl ether (MTBE) is widely used as a fuel additive because of its advantageous properties of increasing the octane value and reducing carbon monoxide and hydrocarbon exhausts. However, MTBE is categorized as a possible human carcinogen. This research investigated the Modified Photo-Fenton system which is based on the Modified Fenton reaction and UV light irradiation. The Modified Fenton reaction is effective for MTBE degradation near a neutral pH, using the ferric ion complex composed of a ferric ion and environmentally friendly organic chelating agents. This research was intended to treat high concentrations of MTBE; thus, 1,000 mg/L MTBE was chosen. The objectives of this research are to find the optimal reaction conditions and to elucidate the kinetic and mechanism of MTBE degradation by the Modified Photo-Fenton reaction. Based on the results of experiments, citrate was chosen among eight chelating agents as the candidate for the Modified Photo-Fenton reaction because it has a relatively higher final pH and MTBE removal efficiency than the others, and it has a relatively low toxicity and is rapidly biodegradable. MTBE degradation was found to follow pseudo-first-order kinetics. Under the optimum conditions, [$Fe^{3+}$] : [Citrate] = 1 mM: 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, and initial pH 6.0, the 1000 ppm MTBE was degraded by 86.75% within 6 hours and 99.99% within 16 hours. The final pH value was 6.02. The degradation mechanism of MTBE by the Modified Photo-Fenton Reaction included two diverse pathways and tert-butyl formate (TBF) was identified to be the major degradation intermediate. Attributed to the high solubility, stability, and reactivity of the ferric-citrate complexes in the near neutral condition, this Modified Photo-Fenton reaction is a promising treatment process for high concentrations of MTBE under or near a neutral pH.

• Journal of the Korean Applied Science and Technology
• /
• v.34 no.4
• /
• pp.874-882
• /
• 2017

As the interest on the air-pollution is gradually rising up at home and abroad, automotiv e and fuel researchers have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward three main issues : evaporative, performance, air pollution. In addition, researcher studied the environment problems of the bio-ethanol, bio-butanol, bio-ETBE (Ethyl Tertiary Butyl Ether), MTBE (Methyl Tert iary Butyl Ether) fuel contained in the fuel as octane number improver. The researchers have many dat a about the health effects of ingestion of octane number improver. However, the data support the con clusion that octane number improver is a potential human carcinogen at high doses. Based on the bio-fuel and octane number improver types (bio-ethanol, bio-butanol, bio-ETBE, MTBE), this paper dis cussed the influence of gasoline fuel properties on the evaporative emission characteristics. Also, this p aper assessed the acceleration and power performance of gasoline vehicle for the bio-fuel property. As a result of the experiment, it was found that all the test fuels meet the domestic exhaust gas standards, and as a result of measurement of the vapor pressure of the test fuels, the bio - ethanol : 15 kPa and the biobutanol : 1.6 kPa. thus when manufacturing E3 fuel, Increasing the biobutanol content reduces evaporation gas and vapor pressure. In addition, Similar accelerating and powering performance was shown for the type of biofuel and when bio-butanol and bio-ethanol were compared accelerated perf ormance was improved by about 3.9% and vehicle power by 0.8%.

• Journal of Food Hygiene and Safety
• /
• v.37 no.6
• /
• pp.385-393
• /
• 2022

The contamination level of inorganic arsenic, a human carcinogen, was investigated in 87 grains and 66 processed grain foods. Two inorganic arsenic species arsenite (As(III)) and arsenate (As(V)) and four organic arsenic monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, arsenocholine were analyzed using HPLC-ICP/MS with high separation and sensitivity and ICP/MS was used to quantify total arsenic. Inorganic arsenic was detected in all grains. And the total arsenic in grains consists of about 70-85% inorganic arsenic and about 10-20% DMA. The concentration of inorganic arsenic was high in rice and black rice cultivated in paddy soil with irrigated water, while the miscellaneous grain in field was low. Mean concentration of inorganic arsenic in rice germ, brown rice and polished rice was 0.160 mg/kg, 0.135 mg/kg, 0.083 mg/kg, respectively, indicating that rice bran contains more arsenic. In processed grain foods, inorganic arsenic concentration varied according to the kind of ingredients and content, and the detection amount was high in processed food with brown rice and germ. The arsenic content of all samples did not exceed each standard, but the intake frequency is high and it is considered that continuous monitoring is necessary for food safety.