Human Health Risk Assessment of Benzene from Industrial Complexes of Chungcheong and Jeonla Province Yong-Chul Jang* Sungwoo Lee* YongSeung Shin** Heekap Kim*** Jonghyun Lee**** Department of Environmental Engineering, Chungnam National University*, Korea Environment Institute** Department of Environmental Science, Kangwon National University***, NEOENBIZ**** (Manuscript received 26 March 2011; accepted 12 August 2011) Abstract This research studied human health risk assessment of benzene from industrial complexes of Chungcheong Province (Seosan industrial complex) and Jeonla Province (Iksan industrial complex and Yeosoo industrial complex). The residents near the industrial complexes areas can be often exposed to volatile organic compounds (e.g., benzene, toluene, xylenes) through a number of exposure pathways, including inhalation of the organic pollutant via various environmental matrices (air, water and soil), contaminated water, and soil intake. Benzene is well known to be a common carcinogenic and toxic compound that is produced from industrial and oil refinery complexes. In this study, a number of samples from water, air, and soil were taken from the residential settings and public school zones located near the industrial complex sites. Based on the carcinogenic risk assessment, the risk estimates were slightly above 1.0 10-6 at all three industrial sites. According to deterministic risk assessment, inhalation was the most important route. The distribution of benzene in the environment would be dependent on vapor pressure, and the physical property influencing the extent of the potential risks. Noncarcinogenic risk assessment of benzene shows that the values of Hazard Index(HI) were much lower than 1.0 at all industrial complexes. Therefore, benzene was not a cause of concern in terms of non-carcinogenic risk posed to the residents near the sites. When compared to probabilistic risk assessment, the CTE(central tendency exposure) cancer risk values of deterministic risk assessment were close to the mean values predicted by the probabilistic risk Corresponding Author: Yong-Chul Jang, Department of Environmental Engineering, Chungnam National University, Gung-dong 220, Yusoeng-gu, Daejeon 305-764, Korea E-mail : gogator@cnu.ac.kr
assessment. The RME(reasonable maximum exposure) values fell within the range of 95% to 99.9% estimated by the probabilistic risk assessment. Since the values of carcinogenic risk assessment were higher than 1.0 10-6, further detailed monitoring and refined risk assessment for benzene may be warranted to estimate more reliable and potential inhalation risks to receptors near the industrial complexes. Keywords : benzene, risk assessment, industrial complex, probabilistic risk assessment, deterministic risk assessment
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ADD = ADD = C air IR inh ET EF ED ABS air _ inh C soil VF CT IR inh ET EF ED ABS air _ inh ADD = C air IR inh FI EF ED ABS air _ inh ADD = ADD = ADD = ADD = C air SA AF EF ED ABS air _ dermal C water FVET shower /(V shower 2)+ET bath /(V bath 2)IR inh W EF ED ABS air _ inh C water IR inh EF ED ABS water _ dermal C water C penetration AF ET EF ED ABS water _ dermal ADD: average daily intake(mg/kg/day), C air : concentration in air (ug/m 3 ) IR inh : inhalation rate (m 3 / ), ET: exposure time(hr), EF: exposure frequency (day) ED: exposure duration(year), ABS air-inh : absorption factor by inhalation(unitless) BW: body weight(kg), AT: averaging time (day), C soil : concentration in soil (mg/kg) VF: volatilization factor(m 3 /kg), CF: conversion factor, IR soil : soil ingestion(mg/day) FI: fraction of intake (unitless), ABS soil-ing : absorption factor by ingestion (unitless). SA: surface area (cm 2 ), AF: adherence factor (mg/cm 2 ), ABS soil-dermal : absorption by dermal contact(unitless), C water :concentration in water (mg/l) FV: Fraction of volatilization (unitless), ET shower : exposure time of shower (hr), V shower : volume of shower room (m 3 ), ET bath : exposure time in bath (hr) V bath : volume of bath area (m 3 ), IR ing : ingestion rate (mg/day), ABS water-ing : absorption factor by water ingestion (unitless), C penetration : dermal penetration factor (cm/hr), ABS water-dermal : absorption factor by dermal contact(unitless) CTE RME ET 24 EF 350 365 minimum extreme (likeliest:20 scale:2) triangular (min:180, max:365, likeliest:350) ED c 79.2 point estimate ED nc 30 point estimate BW 62 82 kg normal(mean:62.0, SD:8.8) AT 10,950 28,908 point estimate IR inh 13 17 m 3 / lognormal(mean:13.0, SD:1.3) ABS air-inh 1 unitless point estimate VF 0.0000708 m 3 /kg point estimate CF 1,000 mg/g point estimate IR soil 50 100 mg/ lognormal(mean:50, SD:5) FI 1 unitless point estimate ABS soil-ing 1 unitless point estimate AF 0.07 mg/cm 2 lognormal(mean:0.07, SD:0.01) ABS soil-dermal 0.1 unitless point estimate
CTE RME FV 0.413 nitless triangular(min:0.176, max:0.413, likeliest:0.413) ET shower 17.2 lognormal(mean:17.2, SD:1.7) V shower 1.91 m 3 uniform(1.3 3) ET bath 5.37 / lognormal(mean:5.37, SD:0.5) V bath 10.9 m 3 uniform(6 50) W 318 L lognormal(mean:318, SD:31.8) IR ing 1.4 2.5 L/ lognormal(mean:1.4, SD:0.1) ABS water-ing 1 unitless point estimate SA 17,084 20,104 cm 2 lognormal(mean:17,084, SD:1,708) C penetration 0.023 cm/ point estimate ABS water-dermal 0.1 unitless point estimate CTE(Central Tendency Exposure), RME(Reasonable Maximum Exposure) Slope Factor Reference Dose (SF, mg/kg-day-1) ) (RfD, mg/kg-day) 2.730 10-2 8.571 10-3 5.500 10-2 4.000 10-3 6.111 10-2 3.600 10-3
m m ( ) 95% UCL (mg/m 3 ) 24 0.39 0.32 0.53 1.37 N.D(0.05 ) (mg/kg) 36 0.10 0.28 0.19 1.61 N.D(0.05 ) (mg/l) 24 0.06 0.09 0.10 0.33 N.D(0.042) (mg/m 3 ) 24 1.11 2.09 1.99 9.61 N.D(0.05 ) (mg/kg) 36 0.07 0.11 0.11 0.44 N.D(0.05 ) (mg/l) 24 0.12 0.40 0.29 1.94 N.D(0.042) (mg/m 3 ) 24 0.70 1.14 1.18 4.53 N.D(0.05 ) (mg/kg) 36 0.21 0.40 0.35 1.88 N.D(0.05 ) (mg/l) 24 0.04 0.08 0.07 0.37 N.D(0.042) N.D = Not Detected(Detection Limit)
CTE 1) 0.0035( 87%) 0.0099( 91%) 0.0062( 93%) RME 2) 0.0049( 83%) 0.0182( 88%) 0.0108( 92%) CTE 0.0001( 2%) 0.0001( 1%) 0.0002( 3%) RME 0.0002( 3%) 0.0001( 1%) 0.0003( 3%) CTE 0.0004( 11%) 0.0009( 8%) 0.0003( 4%) RME 0.0008( 14%) 0.0024( 12%) 0.0006( 5%) CTE 0.0040(100%) 0.0109(100%) 0.0067(100%) (HI) RME 0.0059(100%) 0.0207(100%) 0.0117(100%) 1) CTE(Central Tendency Exposure), 2) RME(Reasonable Maximum Exposure) CTE 1) 2.141 10-6 ( 87%) 6.093 10-6 ( 91%) 3.842 10-6 ( 93%) RME 2) 3.000 10-6 ( 83%) 1.126 10-5 ( 88%) 6.679 10-6 ( 92%) CTE 5.442 10-8 ( 2%) 3.809 10-8 ( 1%) 1.143 10-7 ( 3%) RME 1.088 10-7 ( 3%) 6.299 10-8 ( 1%) 2.004 10-7 ( 3%) CTE 2.676 10-7 (11%) 5.352 10-7 ( 8%) 1.784 10-7 ( 4%) RME 4.955 10-7 ( 14%) 1.437 10-6 ( 12%) 3.469 10-7 ( 5%) CTE 2.463 10-6 (100%) 6.666 10-6 (100%) 4.135 10-6 (100%) (HI) RME 3.604 10-6 (100%) 1.276 10-5 (100%) 7.226 10-6 (100%) 1) CTE(Central Tendency Exposure), 2) RME(Reasonable Maximum Exposure)
Percentile DRA CTE 2.141 10-6 6.093 10-6 3.842 10-6 RME 3.004 10-6 1.126 10-5 6.679 10-6 Min 7.169 10-8 3.044 10-7 2.386 10-7 5% 1.226 10-6 3.311 10-6 2.053 10-6 10% 1.369 10-6 3.702 10-6 2.299 10-6 20% 1.558 10-6 4.219 10-6 2.623 10-6 30% 1.701 10-6 4.612 10-6 2.870 10-6 40% 1.830 10-6 4.963 10-6 3.090 10-6 PRA Median 1.957 10-6 5.309 10-6 3.306 10-6 60% 2.089 10-6 5.669 10-6 3.532 10-6 70% 2.234 10-6 6.066 10-6 3.781 10-6 80% 2.414 10-6 6.561 10-6 4.091 10-6 90% 2.681 10-6 7.291 10-6 4.545 10-6 95% 2.923 10-6 7.951 10-6 4.961 10-6 Max 7.321 10-6 1.995 10-5 1.250 10-5 m
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