2.The Similar Exposure Group and Exposure Variation in Ship-Building Painters: Focused on Xylene Exposure.
Sang Baek KOH ; Young Man ROH ; Hyeon Woo YIM ; Yong Chul SHIN ; Soo Keun KIM ; Hong Ryul CHOI ; Jai Young KIM ; Soung Hoon CHANG
Korean Journal of Occupational and Environmental Medicine 2001;13(4):413-422
OBJECTIVES: This study was conducted to assess the concentration of xylene exposure and exposure variability of a similar exposure group(SEG) in accordance with job title and confined space. METHOD: The study subjects included 28 workers working in the painting process in the ship-building industry. Measurement of subjects were repeated three times. Within and between-worker exposure variance components were estimated from log-transformed exposure concentrations employing a one-way nested random effects analysis of variance model. A uniformly exposed group was defined as one where the between-worker variance(sigmaB2) was less than or equal to 0.031 or bwR95
Confined Spaces
;
Paint
;
Paintings
;
Xylenes*
3.Evaluation of softening ability of Xylene & Endosolv-R on three different epoxy resin based sealers within 1 to 2 minutes - an in vitro study.
Pratima Ramakrishna SHENOI ; Gautam Pyarelal BADOLE ; Rajiv Tarachand KHODE
Restorative Dentistry & Endodontics 2014;39(1):17-23
OBJECTIVES: This study evaluated the efficacy of Endosolv-R and Xylene in softening epoxy resin based sealer after 1 to 2 min exposure. MATERIALS AND METHODS: Sixty Teflon molds (6 mm x 1.5 mm in inner diameter and depth) were equally divided into 3 groups of 20 each. AH 26 (Dentsply/De Trey), AH Plus (Dentsply/De Trey), Adseal (Meta-Biomed) were manipulated and placed in the molds allotted to each group and allowed to set at 37degrees C in 100% humidity for 2 wk. Each group was further divided into 2 subgroups according to the solvents used, i.e. Xylene (Lobachemie) and Endosolv-R (Septodont). Specimens in each subgroup were exposed to respective solvents for 1 and 2 min and the corresponding Vicker's microhardness (HV) was assessed. Data was analysed by Mauchly's test and two-way analysis of variance (ANOVA) with repeated measures, and one-way ANOVA. RESULTS: Initial hardness was significantly different among the three sealers with AH Plus having the greatest and Adseal having the least. After 2 min, Xylene softened AH Plus and Adseal sealer to 11% and 25% of their initial microhardness, respectively (p < 0.001), whereas AH 26 was least affected, maintaining 89.4% of its initial microhardness. After 2 min, Endosolv-R softened AH 26, AH Plus and Adseal to 12.7, 5.6 and 8.1% of their initial microhardness, respectively (p < 0.001). CONCLUSIONS: Endosolv-R was a significantly more effective short term softener for all the tested sealers after 2 min whereas Xylene was an effective short term softener against AH plus and Adseal but less effective against AH 26.
Fungi
;
Hardness
;
Humidity
;
Polytetrafluoroethylene
;
Solvents
;
Xylenes*
5.Modeling the effects of pollutant emissions from large industrial complexes on benzene, toluene, and xylene concentrations in urban areas
Jin Hee BANG ; Inbo OH ; Soontae KIM ; Seunghee YOU ; Yangho KIM ; Ho Jang KWON ; Geun Bae KIM
Environmental Health and Toxicology 2017;32(1):2017022-
This study utilized the Community Multiscale Air Quality model to simulate the spatial distribution of benzene, toluene, and xylene (BTX) concentrations from large national industrial complexes (IC) located in the Ulsan metropolitan region (UMR). Through controlling pollutant emissions from major IC, this study performed a quantitative analysis of the influence of pollutant emissions on BTX concentrations in surrounding urban areas. The results showed that approximately 40% of the annual average BTX concentrations in nearby urban grids were directly influenced by pollutant emissions from the IC. Seasonal modeling results indicated that average BTX concentrations were high around petrochemical complexes, with higher concentrations in the surrounding urban areas during the summer (July). All three of the BTX pollutants showed similar seasonal differences. Daily contributions differed significantly throughout the modeling period, with some values reaching a maximum of 80% during July. Overall, when urban areas were located downwind of the IC, contributions rose. Moreover, this study compared the differences in BTX contributions at each measurement point within the IC and urban areas, which showed that the influence of the IC emissions decreased significantly with distance. The spatial distribution and direct influence of the IC on BTX concentrations in the UMR identified through this study could be used to provide input data in environmental epidemiological studies.
Benzene
;
Epidemiologic Studies
;
Seasons
;
Toluene
;
Ulsan
;
Xylenes
6.Modeling Human Exposure Levels to Airborne Volatile Organic Compounds by the Hebei Spirit Oil Spill.
Jong Ho KIM ; Byoung Kyu KWAK ; Mina HA ; Hae Kwan CHEONG ; Jongheop YI
Environmental Health and Toxicology 2012;27(1):e2012008-
OBJECTIVES: The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. METHODS: We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. RESULTS: Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. CONCLUSIONS: The extent of airborne exposure was clearly not the same as that for normal conditions.
Benzene
;
Humans
;
Petroleum Pollution
;
Toluene
;
Volatile Organic Compounds
;
Volatilization
;
Xylenes
7.Effect of Sodium Benzoate on Change of Urinary Hippuric Acid and Methyl Hippuric Acid among Workers Coexposed to Toluene and Xylene.
Kyunghee JUNG-CHOI ; Sounghoon CHANG ; Hyeongsu KIM ; Wonki OH ; Sang Baek KOH ; Kunsei LEE ; Suekyung PARK
Korean Journal of Occupational and Environmental Medicine 2006;18(3):163-170
OBJECTIVES: This study was performed to investigate the effect of drink containing sodium benzoate on the change of urinary hippuric acid (UHA) and methyl hippuric acid (UMHA) excretion among workers coexposed to low toluene and xylene. METHODS: Study subjects were 55 male shipbuilders who were divided into 3 groups; nonexposed group (n=10, who were not exposed to organic solvent and had drunk sodium benzoate), exposed A group (n=24, who were coexposed to toluene and xylene, and had drunk sodium benzoate), and exposed B group (n=21, who were coexposed to toluene and xylene, and had not drunk sodium benzoate). The study methodology consisted of questionnaire survey, urinary analysis for metabolites of toluene and xylene before and after drinking with or without sodium benzoate, and personal air sampling of toluene and xylene. RESULTS: Before drinking, there was no significant difference in UHA or UMHA between the exposed A and B groups. After 1.5 hour of drinking, UHA of the exposed A group was significantly higher than that of the exposed B group. After 3 hours, however, UHA of the exposed A group was decreased to the level of the exposed B group, regardless of the ambient toluene level. UMHA exhibited no significant difference between the exposed A and B groups regardless of time and ambient toluene level. The regression model showed that drinking of sodium benzoate was positively correlated with UHA after 1.5 hours of drinking, but not after 3 hours. In addition, sodium benzoate didn't affect UMHA. CONCLUSIONS: This study showed that sodium benzoate initially increased UHA temporally but that its effect disappeared after 3 hours. In the medical examination of toluene exposure workers, the ingestion of drink containing sodium benzoate should be forbidden during the 3 hours prior to urinary sampling.
Drinking
;
Eating
;
Humans
;
Male
;
Questionnaires
;
Sodium Benzoate*
;
Sodium*
;
Toluene*
;
Xylenes*
9.Health Risk Assessment and Analysis on the Volatile Organic Compounds in Some Workplace.
Hyo Min LEE ; Myung Soo KIM ; Shin Ai CHOI ; Eun Kyung YOO ; Jong Sei PARK
Korean Journal of Preventive Medicine 1997;30(3):530-539
This study was conducted to assess the health risk on the volatile organic compounds such as toluene, xylene, and styrene in painting workplace. It was monitored through personal air sampling during working time in selected 5 workplaces and analysed using gas chromatography. For the settlement of exposure situation, there were regarded working conditions such as working hours, yearly working days, and working years. Also, Monte-Carlo simulation was used for the induction of hazard index using toxicity value from IRIS(Integrated risk information system) database. The results of risk assessment were summarized as follows : 1. The air concentration of toluene was 7.096+/-15.6 ppm, 2.586+/-4.2 ppm for xylene, 1.914+/-5.3 ppm for styrene in blast painting workplaces. The level of toluene was different significantly compared with the level of xylene and styrene. 2. Computated chronic daily intake value of 95th percentile on toluene, xylene and styrene treated by Monte-Carlo simulation were 9.616, 3.567, 2.782 mg/kg/day, respectively. 3. Computated hazard index value of 75th percentile on toluene, xylene and styrene treated by Monte-Carlo simulation were 3.5, 1.0 and 1.6, respectively. Adverse health effects on the toluene, xylene and styrene would be expected by working exposure in blast painting workplace since the hazard indices of three compounds were exceeded 1 in the surroundings of percenitile 75 through having the low emerged frequency
Chromatography, Gas
;
Humans
;
Paint
;
Paintings
;
Risk Assessment*
;
Styrene
;
Toluene
;
Volatile Organic Compounds*
;
Xylenes
10.Urine Methyl Hippuric Acid Levels in Acute Pesticide Poisoning: Estimation of Ingested Xylene Volume and Association with Clinical Outcome Parameters.
Chi Young CHOI ; NamJun CHO ; Su Yeon PARK ; Samel PARK ; Hyo Wook GIL ; Sae Yong HONG
Journal of Korean Medical Science 2017;32(12):2051-2057
To determine the relationship between the oral ingestion volume of xylene and methyl hippuric acid (MHA) in urine, we measured MHA in 11 patients whose ingested xylene volume was identified. The best-fit equation between urine MHA and ingested amount of xylene was as follows: y (ingested amount of xylene, mL/kg) = −0.052x² + 0.756x (x = MHA in urine in g/g creatinine). From this equation, we estimated the ingested xylene volume in 194 patients who had ingested pesticide of which the formulation was not available. Our results demonstrated that oxadiazole, dinitroaniline, chloroacetamide, organophosphate, and pyrethroid were xylene-containing pesticide classes, while the paraquat, glyphosate, glufosinate, synthetic auxin, fungicide, neonicotinoid, and carbamate classes were xylene-free pesticides. Sub-group univariate analysis showed a significant association between MHA levels in urine and ventilator necessity in the pyrethroid group. However, this association was not observed in the organophosphate group. Our results suggest that MHA in urine is a surrogate marker for xylene ingestion, and high urine MHA levels may be a risk factor for poor clinical outcome with some pesticide poisoning.
Biomarkers
;
Eating
;
Humans
;
Indoleacetic Acids
;
Paraquat
;
Pesticides
;
Poisoning*
;
Respiratory Insufficiency
;
Risk Factors
;
Ventilators, Mechanical
;
Xylenes*