• Environmental Analysis Health and Toxicology
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• v.14 no.3
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• pp.103-111
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• 1999

To effectively predict the lipophilicity, the aryl hydrocarbon receptor (AhR) affinity, and TEF (Toxic equivalency factor) of dioxins by geometrical descriptors, the multiple linear regression methods with the forward selection and backward elimination were employed with statistical validity. The lipophilicity, the Ah receptor binding affinity, and the toxic equivalency factor of dioxins could be predicted using some geometrical descriptors.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.9-9
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• 2003

There are growing concerns about human health effects of dioxin and dioxin like compounds such as polychlorinated dibenzo-p-dioxins (PCDDS), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs), Earlier studies recognized that 2,3,7,8-tetrachloro dibenzo-p-dioxin (TCDD) and structually related dioxin like compounds invoke a number of common toxic responses that are mediated through a high-affinity cytosolic receptor protein, the AhR. Based on studies that Indicate th pivotal role of AhR in mediating most, if not all, of the dioxin toxicity, TCDD equivalency factor (TEF) approach was developed. This approach allowed the expression of toxic potential of a complex mixture as one integrated parameter, the toxic equivalency (TEQ) value.

• Asian Journal of Atmospheric Environment
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• v.7 no.2
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• pp.72-84
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• 2013

In the study, pollution levels of indoor polycyclic aromatic hydrocarbons (PAHs) in public facilities (vapor phase or particulate phase) were evaluated, and a health risk assessment (HRA) was carried out based on exposure scenarios. Public facilities in Korea covered by the law, including underground subway stations, funeral halls, child care facilities, internet cafes (PC-rooms), and exhibition facilities (6 locations for each type of facility, for a total of 48 locations), were investigated for indoor assessment. For the HRA, individual excess cancer risk (ECR) was estimated by applying main toxic equivalency factor (TEF) values suggested in previous studies. Among the eight public facilities, internet cafes showed the highest average $PM_{2.5}$ concentration at $110.0{\mu}g/m^3$ (range: $83.5-138.5{\mu}g/m^3$). When assuming a risk of facility exposure time based upon the results of the surveys for each public facility, the excess cancer risk using the benzo(a)pyrene indicator assessment method was estimated to be $10^{-7}-10^{-6}$ levels for each facility. Based on the risk associated with various TEF values, the excess cancer risk based upon the seven types cancer EPA (1993) and Malcolm & Dobson's (1994) assessment method was estimated to be $10^{-7}-10^{-5}$ for each facility. The excess cancer risk estimated from the TEF EPA (2010) assessment was the highest: $10^{-7}-10^{-4}$ for each facility. This is due to the 10-fold difference between the TEF of dibenzo(a,e)fluoranthene in 2010 and in 1994. The internet cafes where smoking was the clear pollutant showed the highest risk level of $10^{-4}$, which exceeded the World Health Organization's recommended risk of $1{\times}10^{-6}$. All facilities, with the exception of internet cafes, showed a $10^{-6}$ risk level. However, when the TEFs values of the US EPA (2010) were applied, the risk of most facilities in this study exceeded $1{\times}10^{-6}$.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.196-196
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• 2003

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.196-196
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• 2003

Food is a significant source of polycyclic aromatic hydrocarbons (PAHs) to which humans are exposed. In this study, we are analysed 14 PAHs in baked and smoked meats known as major source of PAHs, and defined a correlation between benzo(a)pyrene and pyrene to compare estimating risk from human exposure to PAHs with urinary1-hydroxypyrene.(omitted)

• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.219-229
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• 2005

The analytical methods for dioxins in water sample from wastewater to tap water were reviewed. For extraction method, liquid-liquid extraction (LLE) has been widely used, however, this process needs too much time and man power. New approach including solid phase extraction (SPE) is now applicable to large volume of water sample with high extraction efficiency. Column clean up in classical analytical methods were very complex and time consuming procedures during decade. Modifications were tried to decrease solvent and reagents volume. Moreover, use of column connection method has been demonstrated in the environmental matrices. Instrumental configurations also have been improved, in which GC/MS/MS with large volume injection approach can analyze picogram levels. Absolute sensitivities of HRMS increased compared to old versions of double focusing sector type mass spectrometers. Based on these analytical evolutions during last 10 years, we tried to optimize the analytical method for dioxins in water sample from sample extraction to instrumental analysis.

• Analytical Science and Technology
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• v.23 no.2
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• pp.187-195
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• 2010

To assess health risk for the intake among residents after the Hebei Spirit oil spill, 16 Polycyclic Aromatic Hydrocarbons (PAHs) in seafood samples from oil contaminated bay were determined by Gas Chromatography-Mass Spectrometry (GC-MSD) and samples were personally collected and purchased by residents. Samples were hydrolyzed with KOH and extracted with methylene chloride. The extracted solution were cleaned up using silica/florisil column and 16 PAHs were eluted by methylene chloride : n-hexane (1:9) mixture and determined by GC-MSD in Selected Ion Monitoring (SIM) mode. The mean recoveries for 16 PAHs ranged from 79% to 85%. The 16 PAHs levels in 126 samples ranged from 0.17 to $6.04\;{\mu}g$/kg and the TEQBaP (Toxic EQuivalents) levels in 126 samples were calculated using benzo(a)pyrene toxic equivalency factor for individual 16 PAHs and ranged from 0 to $0.91\;{\mu}gTEQ$/kg. The average Benzo(a)pyrene dietary exposure of residents was $5.5{\times}10^{-8}\;mg/kg$ bw/day and the average PAHs chronic dietary exposure was $1.3{\times}10^{-5}\;mg$ TEQ/kg bw/day. The margin of exposure (MOE) and the excess cancer risk and were $1.8{\times}10^6$ and $9.8{\times}10^{-8}$, respectively. Therefore, the assessment result was considered as low concern for health risk.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.21-26
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• 2001

Risk assessment traditionally are conducted on individual chemicals; however, humans are exposed to multiple chemicals in daily life. The organophosphorus (OP) pesticides are considered in a single risk assessment because they act by a common mechanism of toxicity, and there is likely to be expose to multiple OP pesticides simultaneously or sequentially. The OP pesticides act by inhibiting the enzyme acetylcholinesterasc (AChE) and have available extensive database. AChE is widely distributed throughout the body, most importantly in the nervous system. Inhibition of AChE results in accumulation of acetylcholine in the nervous system that results in clinical signs of cholinergic toxicity, including increased salivation and lacrimation, nausea and vomiting, muscle fasciculation, lethargy and fatigue, among others. To conduct an exposure assessment for pesticides in the diet, we need to know the food consumption patterns of the populations, and the pesticide residue levels in the foods that are consumed. This study was conducted to identify cumulative dietary risk due to multiple OP pesticides that can be exposed through various foods. Total 22 food samples including cereals, vegetables and fruits were collected randomly two times from food markets in several sites (4 cities). The subjected foods were selected by regarding of highly consumed foods to general Korean people. The 12 OP pesticides including Acephate, Azinphos-methyl, Chlorpyrifos, and Diazinon were monitored. For the exposure assessment, general adult group of 60 kg body weight was regarded as target population and food consumption data suggested by Lee et al. (2000) were used as consumed value of individual food. Analyses of samples for OP pesticides have been carried out according to the multiclass multiresidue analysis method and acephate and methamidophos analysis method of Korea Food Code. In general the levels of OP pesticides found in the food samples were very low or not detected.

• Asian Journal of Atmospheric Environment
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• v.8 no.1
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• pp.35-47
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• 2014

The purpose of the study is to evaluate the pollution level (gaseous and particle phase) in the public facilities for the PAHs, non-regulated materials, forecast the risk level by the health risk assessment (HRA) and propose the guideline level. PAH assessments through sampling of particulate matter of diameter < 2.5 ${\mu}m$ ($PM_{2.5}$). The user and worker exposure scenario for the PAHs consists of 24-hour exposure scenario (WIES) assuming the worst case and the normal exposure scenario (MIES) based on the survey. This study investigated 20 PAH substances selected out of 32 substances known to be carcinogenic or potentially carcinogenic. The risk assessment applies major toxic equivalency factor (TEF) proposed from existing studies and estaimates individual Excess Cancer Risk (ECR). The study assesses the fine dusts ($PM_{2.5}$) and the exposure levels of the gaseous and particle PAH materials for 6 spots in each 8 facility, e.g. underground subway stations, child-care facilities, elderly care facilities, super market, indoor parking lot, terminal waiting room, internet caf$\acute{e}$ (PC-rooms), movie theater. For internet caf$\acute{e}$ (PC-rooms) in particular, that marks the highest $PM_{2.5}$ concentration and the average concentration of 10 spots (2 spots for each cafe) is 73.3 ${\mu}g/m^3$ (range: 6.8-185.2 ${\mu}g/m^3$). The high level of $PM_{2.5}$ seen in internet cafes was likely due to indoor smoking in most cases. For the gaseous PAHs, the detection frequency for 4-5 rings shows high and the elements with 6 rings shows low frequency. For the particle PAHs, the detection frequency for 2-3 rings shows low and the elements with 6 rings show high frequency. As a result, it is investigated that the most important PAHs are the naphthalene, acenaphthene and phenanthrene from the study of Kim et al. (2013) and this annual study. The health risk assessment demonstrates that each facility shows the level of $10^{-6}-10^{-4}$. Considering standards and local source of pollution levels, it is judged that the management standard of the benzo (a)pyrene, one of the PAHs, shall be managed with the range of 0.5-1.2 $ng/m^3$. Smoking and ventilation were considered as the most important PAHs exposure associated with public facility $PM_{2.5}$. This study only estimated for inhalation health risk of PAHs and focused on the associated cancer risk, while multiple measurements would be necessary for public health and policy.