• 한국환경과학회지
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• 제21권9호
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• pp.1031-1041
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• 2012

This study was carried out to investigate the characteristics of disinfection by-products (DBPs-trihalomethanes (THMs), haloacetic acids (HAAs) and haloacetonitriles (HANs) formation in chlorination of principal raw waters used for drinking water on Jeju Island, Korea. The domestic water supply of other area and humic acid solution (HA) were used as a reference point. The effects of chlorine contact time, solution temperature and pH on DBPs formation potential (DBPFP) were investigated for raw waters. In addition, the effect of $Br^-$ was studied for HA. The DBPFP (THMFP, HAAFP and HANFP) were increased with increasing chlorine contact time. Comparing the individual DBPFPs for raw waters, they decreased in the order of HAAFP > THMFP ${\geq}$ HANFP. As the solution temperature was increased, the THMFP, HAAFP and HANFP increased. With increasing the solution pH, the THMFP was increased, but HAAFP and HANFP were decreased. With the addition of 0.3 mg/L $Br^-$ for HA, the DBPFP was increased and the major chemical species changed: from trichloromethane to dibromochloromethane and tribromomethane for THMs; from dichloroacetic acid and trichloroacetic acid to tribromoacetic acid for HAAs; and from dichloroacetonitrile to dibromoacetonitrile for HANs.

• Environmental Analysis Health and Toxicology
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• 제14권1_2호
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• pp.35-43
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• 1999

A number of disinfection by-products (DBPs) are formed as a result of the addition of chlorine into the public water supply and some of them have been suggested to cause adverse health effects on humans. However, the estimation of human ingestion exposure to each DBP has been performed simply by multiplying the concentration of a chemical in the cold tap water by the volume of water consumed during a given period of time. However, a questionnaire concerning water consumptions administered to sixty people residing in Chunchon showed that the volume of tap water consumed accounted for approximately 70% of the total volume of water consumed and that of heated water represented approximately 94% of tap water ingested. Heating durations for water-containing foods (e. g., soups and pot stews) and heated beverages (e. g., barley tea) were grouped into 10, 20, 30, and 35 minutes. Based on these time frames, an aluminum pot containing one liter of tap water was heated for the above respective time periods using a gas range to determine the variations of the concentrations of individual DBPs by heating. The pH and total residual chlorine were measured before and after heating. Collected water samples were carried to the laboratory and analyzed for eight DBPs and total organic carbon. Chloroform, bromodichloromethane, chloral hydrate, 1, 2-dichloro-2-propanone, 1, 1, 1-trichloropropanone, and dichloroacetonitrile were not detected following heating for 10 minutes and longer. The concentration of dichloroacetic acid (DCAA) was elevated with heating duration, resulting in the averages of 2.0, 3.1, 4.7, and 12 times the initial concentration, respectively, for 10, 20, 30, and 35 minute heating periods. On the other hand, the concentration of trichloroacetic acid (TCAA) decreased with heating duration, with 0.65, 0.40, 0.34, and 0.19 times lower than the initial concentration. Therefore, it is suggested that ingestion exposure to DCAA increases with heating duration but that ingestion exposure to TCAA decreases. In addition, while the amount of DCAA was elevated at the initial time periods (10 or 20 minutes) and then slowly decreased, that of TCAA was rapidly decreased. In conclusion, water-heating processes during cooking influence the concentrations of individual DBPs in the tap water, with lower levels for volatile DBPs and TCAA, and higher levels for DCAA. Therefore, concentration change needs to be taken into consideration in the estimation of human ingestion exposure to DBPs.

• Applied Biological Chemistry
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• 제42권3호
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• pp.256-261
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• 1999

볶은 보리 알과 보리 티백으로부터 일상적인 차를 만드는 과정에 따라 보리차를 제조할 때 염소로 소독된 물로부터 염소소독부산물의 수준이 감소되는지의 여부를 알아보았다. 수돗물과 두 종류의 보리차 중의 여덟가지 염소소독부산물 중에서 여섯 가지의 휘발성화합물들은 10분 동안의 가열한 후에 검출한계 이하가 되었으므로, 비휘발성 화합물인 dichloroacetic acid, trichloroacetic acid 및 총잔류염소에 대해 서로 비교하였다. 가열전후의 상대적인 양의 변화를 비교한 결과, 세 항목 모두 유의적인 차이가 발견되지 않았으며, 원래의 물 중에서 존재하지 않았던 새로운 봉우리들이 기체크로마토그래프/전자포획검출기 (GC/ECD)의 총이온크로마토그램(TIC)상에 나타났다. 증류되고 탈이온화된 물을 이용하여 두 종류의 보리차(알곡과 티백), 옥수수차와 결명차를 제조한 후 액-액 추출법과 기체크로마토그래피/질량선택검출(GC/MSD)을 이용하여 phenol류, furan류, pyrrole류 등 33종의 유기화합물을 분리 확인하였다.

• Korean Chemical Engineering Research
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• 제44권2호
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• pp.216-226
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• 2006

클로로포름(chloroform), 디클로로아세틱에시드(dichloroacetic acid; DCAA), 트리클로로아세틱에시드(trichloroacetic acid; TCAA) 등은 먹는 물의 염소소독 시 발생되는 주요한 소독부산물이다. 이 중 클로로포름과 DCAA는 발암물질로 분류되어 있어 이에 대한 분포특성연구는 서울시의 먹는 물의 안전성을 판단하기 위해 중요하다. 2002~2004년의 3년 동안 배급 수 계통별로 소독부산물을 분석하였다. 이 중 총트리할로메탄(total trihalomethanes; THMs)의 평균 농도가 정수장에서 생산된 물에서는 0.015 mg/L, 직접 각 가정으로 공급되는 직수에서는 0.019 mg/L, 물탱크를 경유해 각 가정으로 공급되는 물탱크 수에서는 0.023 mg/L로 체류시간이 증가함에 따라 그의 농도는 증가하는 것으로 나타났다. 또한, 수온의 영향으로 인해 여름철에 비교적 높은 농도로 검출되었다. THMs 이외의 다른 소독부산물들도 역시 유사한 경향을 나타내었다. 검출된 소독부산물의 양은 환경부 먹는물 수질기준의 1/4~1/6 정도의 낮은 수준이기 때문에 서울시 수돗물은 소독부산물에 있어 항상 안전한 것으로 나타났다.

• 한국환경과학회지
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• 제21권8호
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• pp.1015-1021
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• 2012

Formation of disinfection by-products (DBPs) including trihalomethans (THMs), haloacetic acid (HAAs), haloacetonitriles (HANs) and others from chlorination of algogenic organic matter (AOM) of Microcystis sp., a blue-green algae. AOM of Microcystis sp. exhibited a high potential for DBPs formation. HAAs formation potential was higher than THMs and HANs formation potential. The percentages of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) formation potential were 43.4% and 51.4% in the total HAAs formation potential. In the case of HANs formation potential, percentage of dichloroacetonitrile (DCAN) formation potential was 97.7%. Other DBPs were aldehydes and nitriles such as acetaldehyde, methylene chloride, isobutyronitrile, cyclobutanecarbonitrile, pentanenitrile, benzaldehyde, propanal, 2-methyl, benzyl chloride, (2-chloroethyl)-benzene, benzyl nitrile, 2-probenenitrile and hexanal.

• 한국환경과학회지
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• 제23권9호
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• pp.1635-1642
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• 2014

Haloacetic acids (HAAs) concentrations have been observed to decreased at drinking water distribution system extremities. This decrease is associated with microbiological degradation by pipe wall biofilm. The objective of this study was to evaluate HAAs degradation in a drinking water system in the presence of a biofilm and to identify the factors that influence this degradation. Degradation of monochloroacetic acid (MCAA), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) was observed in a simulated distribution system. The results obtained showed that different parameters came into play simultaneously in the degradation of HAAs, including retention time, water temperature, biomass, and composition of organic matter. Seasonal variations had a major effect on HAAs degradation and biomass quantity (ATP concentration) was lower by 25% in the winter compared with the summer.

• 대한수의학회지
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• 제40권1호
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• pp.72-80
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• 2000

Lipopolysaccharides (LPS) of Pasteurella multocida (P multocida) and several Gram-negative bacterial pathogens were analyzed by methanolysis, trifluoroacetylation and gas chromatography (GC) on a fused-silica capillary column. The GC analysis indicated that LPS prepared from a strain of P multocida by phenol-water (PW) or trichloroacetic acid (TCA) extraction were quite different in chemical composition. However, LPS prepared from Salmonella enteritidis by the two extraction methods were very similar. PW-LPS extracts from different Pasteurella strains of a serotype had essentially identical GC patterns. Endotoxic LPS extracted from 16 different serotypes of P multocida by PW or by phenol-chloroform-petroleum ether procedures yielded chromatograms indicating similar composition of the fatty acid moieties but minor differences in carbohydrate content. When the chemical composition of endotoxic LPS extracted from several Gram-negative bacteria (P multocida, Pasteurella hacmolytica, Haemophilus somnus, Actinobacillus ligniersii, Brucella abortus, Treponema hyodysenteriae, Escherichia coli, Bacteriodes fragilis, Salmonella abortus equi and Salmonella enteritidis) were examined, each bacteria showed a unique GC pattern. The carbohydrate constituents in LPS of various Gram-negative bacteria were quite variable not only in the O-specific polysaccharides but also in the core polysaccharides. The LPS of closely related bacteria shared more fatty acid constituents with each other than with unrelated bacteria.

• 한국수산과학회지
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• 제48권6호
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• pp.857-863
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• 2015

This study characterized the nutrition and taste of commercial salted semi-dried brown croaker Miichthys miiuy (SSD-BC). The mean crude protein content of the commercial SSD-BC was $19.8{\pm}1.7%$ (range, 17.7-23.2%), and the mean crude lipid content was $0.6{\pm}0.3%$ (range, 0.3-1.1%). The total amino acid content ranged from 17.08 to 18.56 g/100 g, except for sample code 5, which was 22.24 mg/100 g and differed significantly from the other samples. The major amino acids in the commercial SSD-BC were aspartic acid, glutamic acid, leucine, and lysine. In the commercial SSD-BC, the calcium ranged from 11.1-21.4 mg/100 g, phosphorus from 148.4-209.2 mg/100 g, and magnesium from 12.2-48.2 mg/100 g. Monoenoic acid (37.1-40.3%) was the most common fatty acid, followed by saturated acid (33.9-36.3%) and polyenoic acid (25.1-29.2%). The prominent fatty acids in the commercial SSD-BC were 16:0 (23.9-26.5%), 16:1n-7 (11.3-13.0%), 18:1n-9 (19.7-21.5%), and 22:6n-3 (6.9-10.7%). The mean trichloroacetic acidsoluble nitrogen content was 248.1 (range, 137.2-334.2) mg/100 g. The evaluation demonstrated that the commercial SSD-BC is rich in nutrition and taste.

• Safety and Health at Work
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• 제2권3호
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• pp.229-235
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• 2011

Objectives: In this study, we summarized the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals which started in 1995 and continued until a $31^{st}$ round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories. Methods: One hundred and eighteen laboratories participated in the $31^{st}$ round robin. The program offers 5 items for inorganic analysis: lead in blood, cadmium in blood, manganese in blood, cadmium in urine, and mercury in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans,trans-muconic acid, and 2,5-hexanedione in urine. Target values were determined by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee. Results: The proficiency rate was below 70% prior to the first round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained in the range of 60-90% and need to be improved up to 90%. Conclusion: The EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of technical documentation for the whole analytical procedure.

• 한국식품조리과학회지
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• 제6권1호
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• pp.33-40
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• 1990

As a series of investigation on the ex-N compounds, the amino acid composition of the naturally grown and cultured prawn meat extracts was analyzed according to the following extraction conditions: 70% ethyl alcohol extraction, alcohol treatment of the same concentration after hot water extraction for 30 min, and 5% TCA treatment. The Protein content and the level of pure protein was 22 .8% and 18.4% in naturally grown prawn muscle, and 21.8% and 15.3% in the cultured prawn muscle, respectively. None protein nitrogenous compounds of the extracts were 4.4% in the naturally grown prawn muscle and 6.5% in the cultured prawn muscle, respectively. According to the different extract condition, ex-N compounds and the amino acid composition and related compounds and the amino acid composition and related compounds showed high level from 5% trichloroacetic acid extraction. The content of ex-N compounds of the cultured prawn muscle was 1033.0mg%. whereas the content of amino acids and related compounds-N was 825.3mg%, nearly reached to 80% to the total extractive nitrogen. A common feature of the free amino acid composition in the extracts of the muscles of the naturally grown and cultured prawn was high contents of glycine, proline, taurine, alanine and hydroxyproline.