Monitoring of Brominated Flame Retardants (BFRs) for the management of Their Contamination in Environments

Brominated flame retardants have the market share of 40%, comparing others because of their low cost and highly effective retardation against the flame. However, their toxic effects in human and properties of the accumulation in the environments have been issued among the international organization such as EU, OECD and etc. It, therefore, was surveyed the classification, toxic effects, and the usage of Brominated flame retardants, the trends for their managements in the world and Korea, and their contaminated levels in Korean Peninsula. In addition, the management directions for them were proposed. Penta, octa, and deca-BDE among brominated retardants will seem to be prohibited by the regulation as a flame retardants for plastics in Europe because of their toxic effects. Although Penta and Octa BDEs was used marginally in Korea, deca-BDE was 27% of brominated flame retardants (49,050 ton) which had been used in 2002. However, risk assessment for brominated retardants might not launched in Korea, yet. These reports demonstrate that toxic brominated retardants such as PBDEs will be assessed for their usage and the level of contamination in the environment in the area of the point sources like the industrial areas, incinerators and etc. However, the law to regulate the hazardous chemicals seems not to be dictated the monitoring of their contamination in the environment. We, therefore, suggest how to evaluate and to monitor the toxic contaminants with EIA (Environmental Impact Assessment) and LCA (Life Cycle Assessment) system. Further, to establish the management system of BFRs (such as the monitering of contamination levels in environments, life cycle assessment, and risk assessment for the toxic chemicals), It can be recommended the law to deal with the method analyzing chemicals will be established, which contains QA/QC (Quality Assurance and Quality Control) to evaluate the analytic capability of the companies to prepare EIS (Environment Impact Statement) or other institutes for analyzing chemicals.ope

Reverse-U incision with V-Y plasty for correction of secondary unilateral cleft lip nasal deformity : Case report

The correction of a cleft lip nasal deformity is challenging because of its complexity and even more difficult when secondary correction of the unilateral cleft lip nose deformity. For an aesthetic appearance of the nose, a well-balanced relationship between nasal protrusion, nostril shape and columellar length are very important and many operative methods have been described such as direct excision of the skin of the alar web, the Z-plasty technique, V-Y plasty technique and the reverse-U incision. In this case report we used the reverse-U incision to extend the nostril size and length and also to reposition the lower lateral alar cartilage of cleft side. And a V-Y plasty was used to correct columellar shortage and close nasal mucosal defect induced by lower lateral alar cartilage traction. In this way, we have achieved a well-balanced relationship between both nostrils. The reverse-U incision with V-Y plasty creates a better nostril contour than does an another method. In this case report, we present secondary unilateral cleft lip nasal deformity who was treated using reverse-U with V-Y plasty method.ope

A Study on the Management Criteria of Chemiclas Impurities for Drinking Water Treatment by Risk Assessment

The principle and methodology of risk assessment was applied to establish the quality standard of potential impurities of drinking water treatment chemicals. The impurities(arsenic, lead, cadmium, chromium, mercury, etc.) are regulated as the contained quantity of chemicals in Korea while they are regulated as the quality standard with the idea of 10% of the national safety drinking water standard in U.S.A(NSF) and Japan(JWWA). According to risk assessment of the current standard implemented in Korea, the excess cancer risk of arsenic and lead were determined in around 10^(-5) and the hazard quotient(HQ) of cadmium and chromium were below 10^(-2), respectively. And the standard concentration of the impurities are regulated as much as 2%~6% of the national drinking water quality standard. The values are more enforced rather than the standards in U.S.A(NSF) and Japan(JWWA) regulating the concentration of impurities the 10% of the national drinking water quality standard. We conclude that the impurities standard of drinking water treatment chemicals should be reconsidered comprehensively concerning the national safety drinking water quality standard and risk assessment.ope

Assessment of the VOCs Concentration Using GIS Method of Seoul

This study was conducted to investigate the practical using of Geographic Information System(GIS) technology which are computer-based systems that are used to store and manipulate geographic information on the air pollution control and management in the macro city. For this study 130 samples were corrected by passive sampler in Seoul (25 distincts) distributed by TM-coordinate during November in 1997 to January 1998, and analysed by GC/MSD for 16 VOCs e.g., toluene, benzene and display using Arc/view GIS(version 3.2, ESRI Inc, U.S.A) for windows. The most VOCs concentration distribution in November, 1997 was higher than that of January, 1998 except benzene and 1,1,2-trichroloethan, bromobenzene. And products of the distribution of VOCs concentration display using GIS technology was effective as well as other display methods(e.g., contouring method, pie or column chart, graduated symbols), especially in mapping and symbolization capabilities for spatial pollutant status evaluation were very effective than other display methods.ope

Comparison of Household Trihalomethanes (THMs) Exposure Associated with Use of Municipal Tap Water Treated with Chlorine or Ozone-Chlorine

Evaluated were household THMs exposure associated with the use of municipal tap water treated with chlorine and with ozone-chlorine. The current study measured the THMs concentrations in the tap water and indoor and outdoor air in the two types of household, along with an estimation of THMs exposure from water ingestion, showering, and the inhalation of indoor air. Chloroform was the most abundant THMs in all three media, yet no bromoform was detected in any sample. Contrary to previous findings, the fall water THMs concentrations exhibited no significant difference between the chlorine and ozone-chlorine treated water. However, the spring median chloroform concentration in the tap water treated with chlorine (17.6 ppb) was 1.3 times higher than that in the tap water treated with ozone-chlorine (13.4 ppb). It is suggested that the effects of the water parameters should be considered when evaluating the advantage of ozone-chlorine disinfection for THMs formation over chlorine disinfection. The indoor air THMs concentration trend was also consistent with the water concentration trend, yet the outdoor air THMs concentrations did not differ significantly between the two types of household. The indoor to outdoor air concentration ratios were comparable with previous studies. The THMs exposure estimates from water ingestion, showering, and the inhalation of indoor air suggested that, for the residents living in the surveyed households, their exposure to THMs in the home was mostly associated with their household water use, rather than the indoor air. The THMs exposure estimates from tap water ingestion were similar to those from showering.ope

Mechanism of hyperalgesia following tissue injury by complete Freund's adjuvant

의학과/박사[한글] 말초조직의 손상은 통증에 대한 반응이 증가하는 통각과민을 유발한다. 이때 무해성 자극에 대해서도 통증을 느끼는 이질통(allodynia)과 자발적 통증, 그리고 통증부위의 확대가 같이 나타난다. 이의 기전에는 말초 통각수용체의 감작뿐 아니라 중추신경계의 변화도 관여하리라 생각하고 있으나 그 기전은 아직 완전히 밝혀지지 않은 상태이다. 따라서 본 연구에서는 랫드의 발바닥에 complete freund's adjuvant(CPA)를 주사하여 염증을 유발 한 후 행동학적 방법으로 통각과민이 일어나는 지를 조사하고 전기생리학적 방법으로 통증을 전달하는 척수후각세포의 활성도를 기록하였으며, 척수후각세포에서 nitric oxide synthase(NOS)가 가지고 있는 nicotinamide adenine dinucleotide phosphate(NADPH)-diaphorase 활성과 통증시 신경세포 활성에 의해 발현되는 c-fos에 대한 면역염색을 시행하였다. 또한 통각과민 현상의 기전에 관여하는 것으로 알려지고 있는 N-methyl-D-aspartate(NMDA) 수용체의 억제제인 MK-801, 그리고 NOS의 억제제인 N**ω -nitro-L-arginine(L-NNA)을 전 처치할 때 통각과민에 어떠한 영향을 미치는 지를 관찰하여 통각과민의 기전에 이들이 어떻게 관여하며 이들간의 상호관계를 알아보고자 하였다. 실험 결과를 요약하면 다음과 같다. 1. CPA를 주사하여 염증성 통증을 유발한 결과 행동학적으로 기계적 이질통(mechanicalallodynia), 기계적 통각과민(mechanical hyperalgesia)과 열 통각과민(thermal hyperalgesia)이 나타났으며, 척수후각세포의 자발적 활성도 및 기계적 자극에 대한 반응이 증가하고 말초수용야의 확대가 나타났으며, 척수후각에서 NADPH-diaphorase 양성 신경세포와 c-fos발현 신경세포의 수가 증가하였다(p<0.05). 2. MK-801을 전 처치한 후 염증을 유발한 결과 행동학적으로 기계적 이질통이 부분적으로, 기계적 통각과민과 열 통각과민이 의의있게 억제되었고(p<0.05), 척수후각세포의 자발적 활성도 및 pinch 자극에 대한 반응이 CFA만 투여한 군에 비해 적었으며(p<0.05), 척수후각에서 NADPH-diaphorase 양성 신경세포와 c-fos발현 신경세포의 수가 CFA만 투여한 군에 비해 현저히 적었다(p<0.05). 3. L-NNA를 전 처치한 후 염증을 유발한 결과 행동학적으로 열 통각과민이 억제되었고(p<0.05), 척수후각세포의 활성도에는 영향을 주지 않았으며, 척수후각에서 NADPH-diaphorase양성 신경세포의 수는 현저히 감소하였으나(P<0.05), c-fos발현 신경세포에는 영향을 미치지 않았다. 이상의 결과로 보아 CFA로 염증성 통증을 유발할 때 통각과민 현상이 나타남을 확인할 수 있었으며, 이때 나타나는 기계적 통각과민의 기전에는 NMDA수용체가, 열 통각과민의 기전에는 NMDA수용체와 NO system이 같이 관여함을 알 수 있었고 NO system은 c-fos의 발현에는 영향을 미치지 않으나, NOS의 활성도 및 c-fos의 발현은 NMDA수용체의 활성에 의존적으로 통각과민의 기전에 관여하는 것으로 생각된다. [영문] After an injury to tissue such as the skin, a phenomenon, hyperalgesia develops. Hyperalgesia is characterized by an increase in the magnitude of pain evoked by noxious stimuli. It has been postulated that in the mechanism of hyperalgesia sensitization of central nervous system such as spinal dorsal horn as well as that of peripheral nociceptor is involved. However, the precise mechanism is still unclear. In present study, we investigated the roles of N-methyl-D-aspartate(NMDA) receptor and nitric oxide(NO) in the mechanism of hyperalgesia, and the relations among them and c-fos. lnjection of complete Freund's adjuvant(CFA) into unilateral hindpaw of Sprague-Dawley rat induced inflammation followed by hyperalgesia. Behavioral studies measuring paw withdrawal responses by von Frey filaments and paw withdrawal latencies by radiant heat stimuli, electro-physiological recordings of wide dynamic range(WDR) neurons in the spinal dorsal horn, and stainings of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase and c-fos immunoreactivity were performed .The effects of MK-801, an NMDA receptor blocker and N**ω -ni1ro-D-arginine(L-NNA), a nitric oxide synthase(NOS) inhibitor were evaluated. The results are summarized as follows: 1. Injection of CFA induced mechanical allodynia, mechanical hyperalgesia and thermal hyperalgesia. And it increased the response of dorsal hors neuronal activity, and increased the number of NADPH-diaphorasepositive neurons and c-fos expression neurons. 2. MK-801 inhibited mechanical hyperalgesia and thermal hyperalgesia induced by CFA. It reduced the increase of spontaneous activity and pinch response of dorsal horn neuron, and reduced the number of NADPH-diaphorase positive neurons and c-fos expression neurons. 3. L-NNA inhibited the thermal hyperalgesia and reduced the number of NADPH-diaphorase positive neurons, but affected neither the dorsal horn neuronal activity nor the number of c-fos expression neurons. These results suggest that in the mechanism of irlechanical hyperalgesia, NMDA receptor is involved and in that of thermal hyperalgesia both NMDA receptor and NO system are involved. And NO system did not affect the expression of c-fos, but c-fos expression and NOS activity were dependent on the activity of NMDA receptor.restrictio

Multi-route trihalomethane exposure in households using municipal tap water treated with chlorine or ozone–chlorine

In Korea, data for multi-route trihalomethane (THM) exposure in households using municipal tap water treated with ozone–chlorine or chlorine are unavailable or very limited. Accordingly, the present study was designed to obtain those data by measurements of the THM concentrations in the tap water and indoor and outdoor air in the two types of households, along with an estimation of THM exposure from water ingestion, showering, and the inhalation of indoor air. Chloroform was the most abundant THM in all three media, yet no bromoform was detected in any sample. Similar to previous findings, the winter chloroform concentration in tap water treated with chlorine (22.1 μg/l, median) was significantly higher than that in the tap water treated with ozone–chlorine (16.8 μg/l, median). However, the summer water chloroform concentrations and summer and winter water concentrations of the other two THMs (bromodichloromethane and dibromochloromethane) exhibited no significant difference between the chlorine and ozone–chlorine-treated water. It was suggested that the effects of the water parameters including biochemical oxygen demand of raw water entering water treatment plants should be considered when evaluating the advantage of ozone–chlorine disinfection for THM formation over chlorine disinfection. The indoor air THM concentration trend was also consistent with the water concentration trend. The indoor to outdoor air concentration ratios were comparable with previous studies. The THM exposure estimates from water ingestion, showering, and the inhalation of apartment indoor air when not in the shower suggested that, for residents living in the surveyed households, their exposure to THMs in the home was mostly associated with their household water uses. The THM exposure estimates from tap water ingestion were similar to those from showering.restrictio

Mechanism of refractory ceramic fiber- and rock wool-induced cytotoxicity in alveolar macrophages.

OBJECTIVES: Man-made vitreous fibers (MMVFs) can induce cytotoxicity in a way similar to that of other particles, including silica and asbestos fibers. However, as yet the mechanism of MMVF-induced cytotoxicity is still not clear. This report aims to clarify the mechanism of MMVF-induced cytotoxicity in the alveolar macrophage (AM). In this mechanism, an attempt to prove the involvement of the adenosine triphosphate (ATP) generation system and the polyinosinic acid-inhibitable scavenger receptors was made. METHODS: Several parameters were observed for cytotoxicity, such as cell viability, the release of lactic dehydrogenase (LDH) and ATP levels in rat AM's that were treated with refractory ceramic fibers (RF2) and rock wool (RW1). A specially designed ATP generation system was used to determine the effect of MMVF on ATP generation. A scavenger receptor ligand was applied to evaluate the relationship between scavenger receptors and MMVF-induced ATP depletion. RESULTS: A 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide (MTT) assay indicated that both RF2 and RW1 caused a decrease in cell viability and this decrease was concentration-dependent. RF2 and RW1 increased the release of LDH with increasing fiber concentration. From these parameters, RF2 was shown to exhibit greater cytotoxicity than did RW1. Both fibers decreased the intracellular ATP content and this decrease was concentration-dependent. The decrease was more pronounced in RW1 than in RF2 at all fiber concentrations. These fibers suppressed succinate-triggered oxygen consumption. Polyinosinic acid, a ligand of the scavenger receptor, inhibited the MMVF-induced decrease in ATP concentration. CONCLUSION: These results suggest that RF2 and RW1 can induce cytotoxicity and ATP depletion in the AM through the polyinosinic acid-inhibitable scavenger receptor. ATP depletion was the important factor in MMVF cytotoxicity, especially by RW1.ope

Characterization of Disinfection By-Products by Chlamydomonas pulsatilla

This study was conducted to evaluate the chlorinated disinfection by-products formation potential(DBPFP) produced from the cell and extracellular product(ECP) of Chlamydomonas pulsatilla after chlorination. Reaction yields of DBPs produced by C. pulsatilla of ECP and the cell were 0.007 μmol/mg·C and 0.808 μmol/mg·C respectively. Also, SUVA values of ECP and the cell were measured as 0.313 L/mg·m and 1.052 L/mg·m respectively. The DOC of cell was found to be lower than that of ECP, while the SUVA value and reaction yields for the cell were higher than those of ECP. For ECP, most of the DBPFP was composed of trihalomethanes (THM; 47.3%) and haloacetonitiles (HAN; 38.83%). THM and HAN were the major DBPFP produced by the cell. Chloroform was found to be the major THM compound; 98.3% for ECP and 99.98% for the cell. Dichloroacetic acid (DCAA) and dichloroacetonitrile (DCAN) were identified as the major haloacetic acid (HAA) ans HAN compounds formed by ECP and the cell as a precursor, respectively. As the chlorine dose was increased, concentrations of DOC, THMs, and HANs were increased. However, the chlorine dose decreased the concentration fo chlorophy Ⅱ-a.ope