OBJECTIVETo investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofilm reactor (FBBR).

METHODSReduction of total organic carbon (TOC), ultraviolet absorbance (UV254), trihalomethane (THM) formation potential (THMFP), haloacetic acid (HAA) formation potential (HAAFP), and ammonia in FBBR were evaluated in detail. Results The reduction of TOC or UV254 was low, on average 12.6% and 4.7%, respectively, while the reduction of THMFP and HAAFP was significant. The reduction of ammonia was 30%-40% even below 3 degrees C, however, it could quickly rise to over 50% above 3degrees C. Conclusions The FBBR effectively reduces CBPs and ammonia in drinking water even at low temperature and seems to be a very promising and competitive drinking water reactor for polluted surface source waters, especially in China.

No abstract available.
Carcinoma, Squamous Cell ; Chlorine ; Photochemotherapy

OBJECTIVETo better understand the mechanism of chlorine resistance of mycobacteria and evaluate the efficiency of various disinfection processes.

METHODSInactivation experiments of one strain Mycobacteria mucogenicum, isolated from a drinking water distribution system in South China were conducted with various chlorine disinfectants. Inactivation efficiency and disinfectant residual, as well as the formation of organic chloramines, were measured during the experiments.

RESULTSThis strain of M. mucogenicum showed high resistance to chlorine. The CT values of 99.9% inactivation by free chlorine, monochloramine and chlorine dioxide were detected as 29.6 +/- 1.46, 170 +/- 6.16, and 10.9 +/-1.55 min. (mg/L) respectively, indicating that chlorine dioxide exhibited significantly higher efficiency than free chlorine and monochloramine. It was also found that M. mucogenicum reacted with chlorine disinfectants more slowly than 5. aureus, but consumed more chlorine disinfectants during longer time of contact. Lipid analysis of the cell construction revealed that 95.7% of cell membrane lipid of M. mucogenicum was composed of saturated long chain fatty acids. Saturated fatty acids were regarded as more stable and more hydrophilic which enabled the cell membrane to prevent the diffusion of chlorine.

CONCLUSIONIt was concluded that different compositions of cell membrane might endow M. mucogenicum with a higher chlorine resistance.

Chlorine ; Computer Simulation ; Computers, Analog ; Diffusion ; Software

The purpose of this study was to investigate effectiveness of sanitization on raw vegetables not heated in foodservice operations. Microbiological examinations of food materials and cooked food with leek Gukgalli were performed in 2 HACCP-implemented foodservices (A and B) appointed by Food and Drug Administrations, and in 2 other foodservices (C and D) not implemented HACCP. 'Washing and sanitizing raw vegetables' were monitored as CCP at A and B foodservices but only washing has been done in pre-preparation at C and D foodservices. Aerobic plate counts of received leek in A and B foodservices were above 10(7) CFU/g indicating very poor microbiological quality. After sanitization treatment (soaking for 5 minutes in chlorine water: chlorine density 50~100 ppm), its aerobic plate counts decreased to 7.06x10(5) CFU/g (A foodservice) and 4.31x10(5) CFU/g (B foodservice), coliform and faecal coliform were not detected. With this result, the effect of microbial reduction by sanitizer was conformed. But, the conditions of leek were still not acceptable by microbiological standards for ready-to-eat foods. After three more times of rinse has been done, the microbial conditions of leek became acceptable. In C and D foodservices, aerobic plate counts of leek showed decreasing trends by 2x4 times of washings but microbiological quality of leek after pre-preparation were unacceptable by microbiological standards for ready-to-eat foods (C foodservice: 3.58x10(5) CFU/g, D foodservice: 1.29x10(9) CFU/g). For the prevention of foodborne illness, sanitizing raw vegetables should be performed during pre-preparation of non-heated foods.
Chlorine ; Hazard Analysis and Critical Control Points ; Hot Temperature* ; Vegetables* ; Water

A study was carried out for purpose of grasping the status of bacteriological contamination of the public wells in Iri city, during the period from 1 to 15 August, 1974. Coliform groups were detected by membrane filter method and physical conditions of the well were checked. 1. The households which used the piped water occupied 70.8 per cent (11,907 households) out of total households Iri city. 2. Temperature of the well water was 38 out of 50 samples (72.0%) with 12.1 to 16.0 degrees C and 9 wells with 10.1 to 12.0 degrees C. 3. The pH values range of the well water was 6.0 to 7.9, 11 cases of 22.0 per cent less than 6.5 and 8 cases of 16.0 per cent more than 7.5. 4. The residual chlorine was found at 15 samples (30.0%) contained 0.1 to 0.5ppm, 9 samples (18.0%), 0.6 to 1.0 ppm after 24 hours of chlorination. 5. Coliform groups were found at 49 out of 50 samples (98.0%) before chlorination when 100ml well waters was tested by membrane filter technique and 15 wells(30.0%) were potable for drinking within 24 hours after chlorination. 6. Coliform groups positive were 23 out of 26 samples (88.5%) with no residual chlorine, 12 out of 16 samples (80.0%) with 0.1 to 0.5ppm and none out of 9 with 0.6 to 1.0ppm.
Chlorine ; Drinking ; Family Characteristics ; Halogenation ; Hand Strength ; Hydrogen-Ion Concentration ; Membranes ; Water

BACKGROUND: A study was performed on the accidental chlorine gas leakage that occurred in a factory of printed circuit boards manufactured without chlorine. Health examination was performed for all 52 workers suspected of exposure to chlorine gas, and their evacuation-related behaviors were observed in addition to analyzing the factors that affected the duration of their acute respiratory symptoms. METHODS: Behavioral characteristics during the incidence of the accidental chlorine gas leakage, the estimated time of exposure, and the duration of subjective acute respiratory symptoms were investigated. In addition, clinical examination, chest radiography, and dental erosion test were performed. As variables that affected the duration of respiratory symptoms, dose group, body weight, age, sex, smoking, work period, and wearing a protective gear were included and analyzed by using the Cox proportional hazard model. RESULTS: Of 47 workers exposed to chlorine gas, 36 (77 %) developed more than one subjective symptom. The duration of the subjective symptoms according to exposure level significantly differed, with a median of 1 day (range, 0–5 days) in the low-exposure group and 2 days (range, 0–25 days) in the high-exposure group. Among the variables that affected the duration of the acute respiratory symptoms, which were analyzed by using the Cox proportional hazard model, only exposure level was significant (hazard ratio 2.087, 95 % CI = 1.119, 3.890). Regarding the evacuation-related behaviors, 22 workers (47 %) voluntarily evacuated to a safety zone immediately after recognizing the accidental exposure, but 25 workers (43 %) delayed evacuation until the start of mandatory evacuation (min 5, max 25 min). CONCLUSIONS: The duration of the subjective acute respiratory symptoms significantly differed between the low- and high-exposure groups. Among the 27 workers in the high-exposure group, 17 misjudged the toxicity after being aware of the gas leakage, which is a relatively high number.
Body Weight ; Chlorine* ; Incidence ; Proportional Hazards Models ; Radiography ; Smoke ; Smoking ; Thorax

The reactive airway dysfunction syndrome (RADS), a subset of irritant-induced asthma, has been described following exposure to various irritant gas. We describe a case of RADS occuring following a single exposure to high levels of chlorine gas in the workplace. No documented pre-existing respiratory illness and atopy was identified. Cough, dyspnea, and wheezing were developed with the single accidental exposure to chlorine gas and methacholine provocation test was positive. He was completely recovered with the treatment of corticosteroid and oxygen therapy.
Angioedema ; Asthma ; Cellulitis ; Chlorine* ; Cough ; Dyspnea ; Eosinophilia ; Hypereosinophilic Syndrome ; Methacholine Chloride ; Oxygen ; Respiratory Sounds

The drinking water in apartment is stored in reservoir tank and thereafter supplied each household. In case the drinking water in stored too long or insanitary, tap water might change in quality. This study was carried out to evaluate the physic-chemical and microbiological conditions of 36 samples of tap water of apartments compared to 18 samples of tap water of independence houses in Taegu City from May to October, 1987. Main findings are summarized as follows: PH values were within normal range in all samples. Samples less than 0.2ppm in residual chlorine accounted for 16.7% in the apartment and 5.6% in the independence house. Nitrite nitrogen was detected 2.8% of apartment samples only. Among the total of 54 samples, 11.1% of the apartment and independence samples were over the normal value in standard plate count. Samples more than 1.8 of most probable number (MPN) accounted for 27.8% in the apartment and 33.3% in the independence house. In result of test for residual chlorine, nitrite nitrogen, standard plate count, and MPN, the proportion of the samples revealed inappropriate in respect of drinking water standards. In case of all sorts of tests was 2.7% in apartment and nothing in independence houses, in case of 3 sorts of tests was 2.7% in apartment and 5.6% in independence houses, in case of 2 sorts of tests was 8.3% in apartment and 5.6% in independence houses, and in case of only 1 test was 25.0% in apartment and 22.2% in independence houses. Correlation between residual chorine and standard plate count, and between standard plate count and MPN were observed. It was found that the more years since construction of apartment were, the worse tap water was in quality.
Chlorine ; Daegu* ; Drinking Water ; Family Characteristics ; Hydrogen-Ion Concentration ; Nitrogen ; Reference Values ; Water*

OBJECTIVES: We report two cases of anosmia that were suspected to be caused by chronic chlorine exposure in cleansing works METHODS: We examined the cases in order to assess the work-relatedness of their anosmia. We conducted olfactory threshold test and olfactory perception test repeatedly at one-month intervals. Using ion chromatography, we analyzed the detergent that the workers had been using for several years before their olfactory function decreased. RESULTS: A 59-year-old male who had worked in a cleansing process for 10 years (1983-1993) and a 58-year-old female who had worked in the same process for 8 years (1987-1995) were diagnosed with anosmia. The cause of the anosmia was presumed to have been the chlorine gas that was generated from the process of heating the detergent-dissolved water, in which chloride was detected. CONCLUSIONS: This is the first report on anosmia due to chronic chlorine exposure. Greater attention needs to be focused on the prevention of anosmia because there are many workers who have been exposed to chlorine gas in chlorine treating and generating processes.
Chlorine* ; Chromatography ; Detergents ; Female ; Heating ; Hot Temperature ; Humans ; Male ; Middle Aged ; Olfaction Disorders* ; Olfactory Perception ; Water