Chlorination of pool water leads to the forma-tion of many by-products, chloroform usually being the most abundant. The paper reports the results of a study evaluating exposure of bath-ers and pool employees to trihal...Chlorination of pool water leads to the forma-tion of many by-products, chloroform usually being the most abundant. The paper reports the results of a study evaluating exposure of bath-ers and pool employees to trihalomethanes (chloroform, bromodichloromethane, dibromo-chloromethane, bromoform) in four indoor swimming pools with chlorinated water. Chlo-roform concentrations in environmental air samples when the pool was in use (about 9 h), in the range 1-182 μg/m3, were greater near the pool than in the change rooms, passageways and offices. Chloroform concentrations in per-sonal air samples of pool employees were in the range 18-138 μg/m3. Urinary concentrations of chloroform averaged (geometric means) 0.123 and 0.165 μg/l and 0.404 and 0.342 μg/l prior and at the end of exposure during in water and out of water activities, respectively. The significant increase in urinary excretion of chloroform confirms that the source of the contaminant was pool water. Absorption of chloroform, estimated from airborne and water concentrations, was significantly correlated with delta chloroform (after/before exposure) and urinary concentra-tions of chloroform at the end of exposure. As chloroform is a toxic and possibly carcinogenic substance, these observations pose a problem principally for the general population of pool users.展开更多
The bacteriological quality of swimming pool water in Port Harcourt Metropolis was investigated. Ten (10) swimming pools were examined for microbial quality. Out of the 10 swimming pools, 4 (2, 4, 7 and 9) had bacteri...The bacteriological quality of swimming pool water in Port Harcourt Metropolis was investigated. Ten (10) swimming pools were examined for microbial quality. Out of the 10 swimming pools, 4 (2, 4, 7 and 9) had bacterial isolates of 40 (100%). Swimming pools 2, 4, 7 and 9 had the bacterial isolates of 10 (25%), 8 (20%), 10 (25%) and 12 (30%), respectively. Of the forty (40) bacterial isolates identified, which represented 100 percent, 22 (55%) were identified as Staphylococcus epidermidis, 10 (25%) Bacillus cereus, 6 (16%) Micrococcus and 2 (5%) Staphylococcus aureus. Among the four swimming pools, 2 and 9 did not have the isolates of Staphylococcus aureus and Micrococcus, respectively. Based on the World Health Organisation (WHO) standard for recreational waters, the absence of coliform and fecal coliform bacteria (E. coli) revealed that the ten (10) swimming pools used for this study are considered to be within the acceptable limits for certifying microbiological water quality. However, there is a need for care and continuous maintenance of the swimming pools.展开更多
New Words找zhao v．speak to,look for别bie adv．don’t担心danxin v．worry游泳池youyongchi n．swimming pool怎么zenme pron．how走zou v．walk,get(to)向xiang prep．to,towards东dong n．east路口lukou n．crossing,junction,int...New Words找zhao v．speak to,look for别bie adv．don’t担心danxin v．worry游泳池youyongchi n．swimming pool怎么zenme pron．how走zou v．walk,get(to)向xiang prep．to,towards东dong n．east路口lukou n．crossing,junction,intersection右you n．right拐guai v．turn,change direction等deng v．wait(for) David is on the phone to Wang Jiaming．They are going for a swim．大卫:喂,我是大卫。我找王家明。展开更多
A swimming pool can be considered as a chemical reactor with specific hydraulic and macro-mixing characteristics. The nature of flow into the pool depends on various characteristics, such as water inlets and outlets (...A swimming pool can be considered as a chemical reactor with specific hydraulic and macro-mixing characteristics. The nature of flow into the pool depends on various characteristics, such as water inlets and outlets (number and position), pool geometry, and flow rate. This study investigates how swimming pool design affects hydraulic behavior based on experimental and computational fluid dynamics studies (CFD). This paper does not describe the hydraulic behavior of all existing swimming pools, however the cases studied here are representative of pool designs widely used in Europe and the United States. The model developed, based on the principle of a stirred reactor, could be used as a first approach in describing the hydraulic behavior of regular pools. This model is suitable for the study of physical and chemical phenomena with long characteristic times. Other, more advanced, models were shown to be more suitable to the case of fast chemical processes.展开更多
文摘Chlorination of pool water leads to the forma-tion of many by-products, chloroform usually being the most abundant. The paper reports the results of a study evaluating exposure of bath-ers and pool employees to trihalomethanes (chloroform, bromodichloromethane, dibromo-chloromethane, bromoform) in four indoor swimming pools with chlorinated water. Chlo-roform concentrations in environmental air samples when the pool was in use (about 9 h), in the range 1-182 μg/m3, were greater near the pool than in the change rooms, passageways and offices. Chloroform concentrations in per-sonal air samples of pool employees were in the range 18-138 μg/m3. Urinary concentrations of chloroform averaged (geometric means) 0.123 and 0.165 μg/l and 0.404 and 0.342 μg/l prior and at the end of exposure during in water and out of water activities, respectively. The significant increase in urinary excretion of chloroform confirms that the source of the contaminant was pool water. Absorption of chloroform, estimated from airborne and water concentrations, was significantly correlated with delta chloroform (after/before exposure) and urinary concentra-tions of chloroform at the end of exposure. As chloroform is a toxic and possibly carcinogenic substance, these observations pose a problem principally for the general population of pool users.
文摘The bacteriological quality of swimming pool water in Port Harcourt Metropolis was investigated. Ten (10) swimming pools were examined for microbial quality. Out of the 10 swimming pools, 4 (2, 4, 7 and 9) had bacterial isolates of 40 (100%). Swimming pools 2, 4, 7 and 9 had the bacterial isolates of 10 (25%), 8 (20%), 10 (25%) and 12 (30%), respectively. Of the forty (40) bacterial isolates identified, which represented 100 percent, 22 (55%) were identified as Staphylococcus epidermidis, 10 (25%) Bacillus cereus, 6 (16%) Micrococcus and 2 (5%) Staphylococcus aureus. Among the four swimming pools, 2 and 9 did not have the isolates of Staphylococcus aureus and Micrococcus, respectively. Based on the World Health Organisation (WHO) standard for recreational waters, the absence of coliform and fecal coliform bacteria (E. coli) revealed that the ten (10) swimming pools used for this study are considered to be within the acceptable limits for certifying microbiological water quality. However, there is a need for care and continuous maintenance of the swimming pools.
文摘New Words找zhao v．speak to,look for别bie adv．don’t担心danxin v．worry游泳池youyongchi n．swimming pool怎么zenme pron．how走zou v．walk,get(to)向xiang prep．to,towards东dong n．east路口lukou n．crossing,junction,intersection右you n．right拐guai v．turn,change direction等deng v．wait(for) David is on the phone to Wang Jiaming．They are going for a swim．大卫:喂,我是大卫。我找王家明。
文摘A swimming pool can be considered as a chemical reactor with specific hydraulic and macro-mixing characteristics. The nature of flow into the pool depends on various characteristics, such as water inlets and outlets (number and position), pool geometry, and flow rate. This study investigates how swimming pool design affects hydraulic behavior based on experimental and computational fluid dynamics studies (CFD). This paper does not describe the hydraulic behavior of all existing swimming pools, however the cases studied here are representative of pool designs widely used in Europe and the United States. The model developed, based on the principle of a stirred reactor, could be used as a first approach in describing the hydraulic behavior of regular pools. This model is suitable for the study of physical and chemical phenomena with long characteristic times. Other, more advanced, models were shown to be more suitable to the case of fast chemical processes.
文摘本文拟建立二乙酰一肟-氨基硫脲测定游泳池中尿素的方法,从波长的选择、酸度的条件、试剂的加入量、温度的条件、加热时间来寻求最佳条件。结果表明:实验最理想条件是在酸性条件,线性方程结果良好,r=0.999 6,检测波长为480 nm,混合酸溶液加入量为5.00 m L,二乙酰一肟-氨基硫脲溶液加入量为2 m L,加热时间为20 min,线性范围为0~10 mg/L。该方法检测结果良好,可用于游泳池中的尿素测定。
文摘中西太平洋热带海域是世界上最大的鲣(Katsuwonus pelamis)渔场。为合理开发和利用中西太平洋围网鲣自由鱼群的渔业资源,根据1995—2019年中西太平洋渔业委员会的围网鲣数据计算资源丰度指数,得出渔场重心,并结合海表温度(Sea surface temperature,SST)、海洋尼诺指数(Oceanic Niño Index,ONI)进行皮尔森相关性分析。结果显示,单位捕捞努力量渔获量(Catch per unit effort,CPUE)可用于表征自由鱼群渔场重心的资源丰度,且与暖池重心经度以及右边缘经度有显著相关性;渔场重心与暖池指标(暖池重心经度与右边缘经度)的相对位置以及变动趋势在不同气候模式下存在差异,而在同一气候模式中相同。结果表明,渔场重心可通过暖池重心的变化进行预测,而通过构建暖池场与自由鱼群资源丰度的时空分布关系发现,暖池右边缘能够与自由鱼群的空间分布产生联系,为商业性捕捞围网鲣自由鱼群提供渔场边界的指示,为其资源开发与养护提供科学依据。
