• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.31-34
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• 2000

The contents of hexachlorobenzene (HCB), a hazardous impurity, in chlorothalonil were monitored through 1996 to 2000. The number of samples were 32 from three different sources. The contents determined by GLC/ECD were ranged from 0.0036% to 0.0330% with average content of 0.0219%. All the samples were recorded below 0.05%, which is the regulation standard of HCB in the technical. The total input of HCB in Korean agriculture was calculated to be approximately 77 kg a year.

• 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 Wetlands Research
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• v.9 no.1
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• pp.107-114
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• 2007

This study aimed to investigate the hexachlorobenzene (HCB) dechlorinating ability of sediment microbes collected from a natural canal receiving secondary effluents from an industrial estate and nearby factories. Nine sites along the stream and one in the estuary in the Gulf of Thailand into which the canal spills were specified and sampling for sediment and water. Preliminary analysis of the sediments showed that the first four sites nearest to the discharging location were contaminated by HCB within the range of 0.18 to 1.25 ppm. Apart from that, 1,3,5-trichlorobenzene which has never been commercially produced or used in any manufacturing processes except for the transformation from higher chlorinated benzene was also identified in the range of 0.16 to 0.24 ppm. This suggested a possibility of sporadically HCB contamination in this stream. Of more important, people in the community along this canal earn their living by coastal fishery; hence, posing a risk of spreading HCB and its less chlorinated congeners via food chain from caught marine creatures to human. As a result, there is an urgent need to understand the behavior of HCB dechlorination in this stream sediment which can lead to a clean-up action in the future. Serum bottles with sediment slurries (sediment to water ratio of 1:1 (v/v) and filtered to remove particles larger than 0.7 mm) from each site were inoculated with 2 mg/l of HCB, kept anaerobically in the dark at room temperature without any nourishment, and analyzed for HCB and its less-chlorinated congeners every 6 days. Total chemical oxygen demand, suspended solids, and volatile suspended solids were in the range of 21,492-73,584, 158,100-518,100 and 6,000-32,700 mg/l, respectively. It was found that all sediment slurries began to dechlorinate HCB in 12 to 30 days and the HCB was completely removed within 42 to 60 days or so. On the other hand, there was no HCB dechlorination occurred in the controlled set which was sterilized by autoclaving prior to the addition of HCB. This implies that the HCB transformation was solely due to microorganisms' activities. HCB was dechlorinated principally via pentachlolobenzene to 1,2,3,5-tetrachlorobenzene and terminated at 1,3,5-trichlorobenzene which is the major pathway as reported by many researchers. Dichlorobenzene has not been detected in any samples within the dechlorination period of 60 days. The results indicate that the microbial matrix in the sediment of this stream has an outstanding capability to dechlorinate HCB. Existing substrates and nutrients which mainly sorbed onto the solid phase and the typical temperature in Thailand were sufficient and suitable to promote the activities of these HCB-dechlorinating microbes.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.179-186
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• 2009

Hexachlorobenzene (HCB) is a bioaccumulative, persistent, and toxic pollutant. HCB is one of the 12 priority of Persistent Organic Pollutants (POPs) intended for global action by the United Nations Environment Program (UNEP) Governing Council. POPs are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Some of HCB is ubiquitous in air, water, soil, and biological matrices, as well as in major environmental compartments. HCB has effects on various organs such as thyroid, bone, skin, kidneys and blood cells and especially, revealed strong toxicity to liver. In this study, we identified genes related to hepatotoxiciy induced by HCB in human hepatocellular carcinoma (HepG2) cells using microarray and gene ontology (GO) analysis. Through microarray analysis, we identified 96 up- and 617 down-regulated genes changed by more than 1.5-fold by HCB. And after GO analysis, we determined several key pathways which known as related to hepatotoxicity such as metabolism of xenobiotics by cytochrome P450, complement and coagulation cascades, and tight junction. Thus, our present study suggests that genes expressed by HCB may provide a clue for hepatotoxic mechanism of HCB and gene expression profiling by toxicogenomic analysis also affords promising opportunities to reveal potential new mechanistic markers of toxicity.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.237-238
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• 2000

최근 산업사회의 발전에 따라 수계 오염문제가 심각하게 대두되고 있다. 따라서 이들 오염물질에 대한 모니터링을 위한 방법들이 강구되고 있으며, 이 중에서 어류 간의 cytochrome P450 호소계는 지방친화성 물질의 오염상태를 평가할 수 있는 물질로 알려지고 있다(Payne et al., 1987). PCBs(Polychlorinated biphenyls)와 HCB(Hexachlorobenzene)는 유기염소계 화합물로서 환경중에 널리 분포하고 있으며, 이중 PCBs는 신경계, 면역계 및 내분비계 등 생체내에 미치는 영향이 크므로 내분비장애물질(endocrine disruptor)로 분류되고 있고, HCB는 독성이 강한 화합물로서 주로 농업에서 fungicide로서 사용되어 왔으며. 다양한 산업 연소과정의 부산물로 발생되고 있다. (중략)

• Journal of Wetlands Research
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• v.10 no.2
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• pp.23-37
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• 2008

The vertical distribution of dioxins and hexachlorobenzene(HCB) in a sediment core was investigated to elucidate historical trends of dioxins and HCB deposited into Upo wetland. The total concentration of dioxin ranged from 8.7 to 66.27 pg/g-dw in Upo sediments deposited, and from 17.64 to 97.03 pg/g-dw in Mokpo. Dioxin fluxes increased from the first-1990s and then reached a maximum in the mid-1990s. The major source of dioxin by comparing the congeners pattern was pentachlorophenol(PCP) used of agrochemicals. The HCB concentration in most of samples was detected below the MDL(Method Detection Limit of 0.5ng/g), except a few samples.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.335-344
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• 2012

Hexachlorobenzene (HCB) and Dichloro-Diphenyl-Trichloroethane (DDT) were determined in surface sediments collected from main rivers of Korea. Concentration of HCB in sediments ranged from 0.41 to 3.82 (average 1.58) ng/g, 0.08 to 6.09 (average 0.90) ng/g, 0.02 to 0.97 (average 0.30) ng/g, 0.28 to 0.59 (average 0.42) ng/g and 0.23 to 0.48 (average 0.32) ng/g in Han river, Nakdong river, Geum river, Yeongsan and Seomjin river respectively. The DDTs concentration was ranged from 0.67 to 14.20 (average 4.76) ng/g, N.D. to 10.36 (average 1.81) ng/g, N.D. to 7.26 (average 1.87) ng/g, N.D. to 3.12 (average 1.08) ng/g and 0.02 to 2.04 (average 0.56) ng/g in Han river, Nakdong river, Geum river, Yeongsan and Seomjin river respectively. In comparison with the concentration of HCB and DDTs in other studies, the values in sediments of this study were lower than those of other countries. Comparison with that Sediment quality guideline (SQG) of National Oceanic and Atmospheric Administration (NOAA), the HCB levels of this study were very lower than Effect Range Low (ERL) value. In the case of DDTs, the concentrations of 46 points were higher than ERL (1.58 ng/g). It have not harmful effect on ecosystem of the sediment, however ongoing monitoring of sediments is deemed necessary.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.110-114
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• 2002

The study was carried out to investigate the changes of haematological constituents induced by dietary exposure of Hexachlorobenzene (HCB) and Polychlorinated biphenyls (PCBs) in nile tilapia, Oreochhromis niloticus. The nile tilapia were fed pellet with 0.05, 0.25 and 0.50 mg/kg body weight/day of HCB and PCBs for 30 days, respectively. HCB ($\ge$ 0.25 mg/kg) induced a significantly decreased the red blood cell count at 30 days, and the hemoglobin concentration and hematocrit value were significantly decreased after 20 days to 0.50 mg/kg. The diminution of red blood cell count, hemoglobin concentration and hamatocrit value by PCBs was found after 20 days at $\ge$0.25 mg/kg. The concentrations of calcium decreased significantly at 30 days at $\ge$0,25 mg/kg of PCBs-diet. However, magnesium and inorganic phosphorus did not show any noticeable changes in the range of 0.05$\~$o.50 mg/kg of HCB and PCBs compared to control group during the experimental period, The low concentration of total protein was observed at the last day of experiment to 0.50 mg/kg of HCB-diet, while total protein initiated to increase from 20 days at the 0.25 mg/kg of PCBs-diet. The glucose was significantly increased after 20 days at $\ge$0,25 mg/kg of HCB and PCBs, A significant increment GOT and GPT activities was noticed after 20 days at 0.50 mg/kg of HCB and PCBs, These results indicate that hematological and serum biochemical changes in the nile tilapia by dietary exposure to HCB and PCBs are affected at more than 0,25 mg/kg after 20 days.

• Journal of Life Science
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• v.22 no.3
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• pp.332-339
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• 2012

Horizontal distributions and their ecotoxicological implications relating to organochlorine compounds (OCs) were determined in surface sediments sampled from the West Nakdong River. The concentrations of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and hexachlorobenzene (HCB) in surface sediments were in the range of 0.57-3.68, 0.41-8.35, 0.63-1.65, and n.d.-0.56 ng/g, respectively. DDTs represent the major OC in the West Nakdong River. Concentrations of PCBs and DDTs correlate with the total organic carbon (PCBs: r=0.874, p<0.001, and DDTs: r=0.762, p<0.05, respectively), indicating that organic content in the sediments is one of the major factors for influencing horizontal distribution of the organochlorine compounds in this river. Examining the potential poisonous character of the surface sediments to benthic organisms according to the sediment quality guideline (SQG), set out by the Canadian Council of Ministers of the Environment (CCME) and the National Oceanic and Atmospheric Administration (NOAA), we found that the concentrations of total PCBs, p,p'-DDD, and ${\gamma}$-HCH were lower than the effects range-low (ER-L) and the probable effects level (PEL). As a result, it is considered that the effect of organochlorines in the region considered on benthic organisms is very low from the perspective of environmental toxicology. However, in terms of the Canadian SQC, p,p'-DDE, p,p'-DDT, and total DDTs, respectively, exceeded the interim sediment quality guidelines (ISQG) and the threshold effect level (TEL) in 30%, 17%, and 19%, respectively, of the sediment samples analyzed.

• Environmental Engineering Research
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• v.14 no.4
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• pp.226-236
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• 2009

The performance of phytoremediation has proven effective in the removal of nutrients and metals from aqueous systems. However, little information is available regarding the behavior of pesticides and their removal pathways in aquatic environments involving plant-uptake. A detailed understanding of the kinetics of pesticide removal by plants and information on compound/plant partition coefficients can lead to an effective design of the phytoremediation process for anthropogenic pesticide reduction. It was determined that the reduction rates of four organophosphorus (OP) and two organochlorine (OC) pesticides (diazinon, fenitrothion, malathion, parathion, dieldrin, hexachlorobenzene [HCB]) could be simulated by first-order reaction kinetics. The magnitude of k was dependent on the pesticide species and found within the range of 0.409 - 0.580 $d^{-1}$. Analytical results obtained by mass balances suggested that differential chemical stability, including diversity of molecular structure, half-lives, and water solubility, would greatly influence the removal mechanisms and pathways of OPs and OCs in a phytoreactor (PR). In the case of OP pesticides, plant accumulation was an important pathway for the removal of fenitrothion and parathion from water, while pesticide sorption in suspended matter (SM) was an important pathway for removal of dieldrin and HCB. The magnitude of the pesticide migration factor (${\Large M}_p^{pesticide}$) is a good indication of determining the tendency of pesticide movement from below- to above-ground biomass. The uncertainties related to the different phenomena involved in the laboratory phyto-experiment are also discussed.