Swimming pool waters

Calcium Hypochlorite. This chemical, marketed since 1928, is one of the most widely used swimming-pool water sanitizers. Calcium hypochlorite, a crystalline sofld, is a convenient source of available chlorine and is sold in granular or tablet form for use in home, semiprivate, and commercial pools. When dissolved in water, Ca(OCl)2 forms hypochlorous acid and hypochlorite ion similar to NaOCl. It contains small amounts of stabilizing Ca(OH)2, which has a very small effect on pool pH (7). Calcium hypochlorite has superior storage stabiUty and much higher available CI2 concentration than Hquid bleach, which reduces storage requirements and purchasing frequency. 

The pH of swimming pool water is a function of the following equiUbria ... 

Sta.bilizers. Cyanuric acid is used to stabilize available chlorine derived from chlorine gas, hypochlorites or chloroisocyanurates against decomposition by sunlight. Cyanuric acid and its chlorinated derivatives form a complex ionic and hydrolytic equilibrium system consisting of ten isocyanurate species. The 12 isocyanurate equilibrium constants have been determined by potentiometric and spectrophotometric techniques (30). Other measurements of two of the equilibrium constants important in swimming-pool water report significantly different and/or less precise results than the above study (41—43). A critical review of these measurements is given in Reference 44. 

The basic principles of swimming-pool water treatment also apply to spas and hot tubs. However, spas and tubs are not miniature swimming pools but are unique in treatment requkements because of use patterns and a high ratio of bather to water. Eor example, four people in a 1.9-m (500-gal) spa or tub have a sanitizer demand equal to 160 people in a 75.7-m (20,000-gal) swimming pool. 

The equihbrium constant for the first reaction is 2.40 x 10 at 25°C (179). When cyanuric acid is used in conjunction with a hypochlorite for sanitising swimming pool water, the free available chlorine is kept in the 1 to 3 ppm range. 

The Polyquats or polymerized quaternary salt. If we study the list of algicides approved by the DETR Committee on pages 107 and 108 in the book Swimming Pool Water published by the Pool water treatment Advisory group, we observe the Polyquats WSCP (or BUSAN 77), WSCP-2 (or BUSAN 79) and APCA (or BUSAN 1055) and their impact on Hazard and Incompatibility data . Indeed, these quats have a very low toxicity and are compatible with most swimming pool chemicals used. 

Trends in chemical treatment of swimming pool water across Europe are outlined. These relate entirely to the use of dry chlorine, comprising stabilised chlorine and calcium hypochlorite. Results from a recent UK survey are also summarised. 

Research into swimming pool water treatment has been conducted on both the bench and pilot scale at the School of Water Sciences at Cranfield University over the past six years. Much of this has been sponsored jointly by the Engineering and Physical Sciences Research Council (EPSRC) and the Pool Water Treatment Advisory Group (PWTAG). The most recent work has been based on a 2.2m3-capacity pilot plant (Figure 5), a one-seventh linear scale model of an actual operating pool, incorporating all conventional unit... 

Swimming pools must be kept around a neutral pH in order for people to swim in them comfortably. Swimming pool water that is too acidic can burn a swimmer s eyes or nose. It also makes the skin dry and itchy and destroys bathing suits much faster than a neutral pH. Acidic water not only destroys bathing suits, it can dissolve the materials used to build the pool, such as marble or plaster. 

A. Schwake, B. Ross, and K. Cammann, Chrono amperometric determination of hydrogen peroxide in swimming pool water using ultramicroelectrode array. Sens. Actuators, B B 46, 242-248 (1998). 

Copaken J. 1990. Trihalomethanes Is swimming pool water hazardous. In Water chlorination Chemistry, Environmental Impact and Health Effects, volume 6. Chelsea, MI Lewis Publishers, Inc. 

Shi and Adams recently created a rapid IC/ICF-MS method for simultaneously measuring iodoacetic acids, bromoacetic acids, iodate, and bromate in drinking water, groundwater, surface water, and swimming pool water [165]. Method detection limits were sub-pg/L for iodinated DBFs, and low-pg/L for brominated DBFs. 

Terasaki M, Makino M (2008) Determination of chlorinated by-products of parabens in swimming pool water. Int J Environ Anal Chem 88(13) 911-922... 

Zwiener C, Richardson SD, DeMarini DM, Grummt T, Glauner T, Frimmel FH (2007) Drowning in disinfection byproducts Assessing swimming pool water. Environ Sci Technol 41 363-372... 

Weaver WA, Li J, Wen YL, Johnston J, Blatchley MR, Blatchley ER III (2009) Volatile disinfection by-product analysis from chlorinated indoor swimming pools. Water Res 43 3308-3318... 

Richardson SD, DeMarini DM, Kogevinas M, Fernandez P, Marco E, Lourencetti C, Balleste C, Heederik D, Meliefste K, McKague AB, Marcos R, Font-Ribera L, Grimalt JO, Villanueva CM (2010) What s in the pool A comprehensive identification of disinfection by-products and assessment of mutagenicity of chlorinated and brominated swimming pool water. Environ Health Perspect 118(11) 1523-1530... 

Amer K, Karanfil T (2011) Formation of disinfection by-products in indoor swimming pool water. The contribution from filling water natural organic matter and swimmer body fluids. Water Res 45 926-932... 

Activated charcoal or carbon is widely used for vapour adsorption and in the removal of organic solutes from water. These materials are used in industrial processes to purify drinking water and swimming pool water, to de-colorize sugar solutions as well as other foods, and to... 

It is worthwhile mentioning that ozone is frequently used for swimming pool water clean-up prior to a chlorine disinfection step. According to Bohme (1999) almost 3600, i. e. more than 50 % of the ozone generators sold by German companies between 1954 and 1997, have been efficiently applied in this field. 

Worst case is used in risk assessments to describe an extreme assumption, choice, or value intended to fulfill the goal of being health-protective - that is, selected to be reasonably certain that exposure or risk is not underestimated and to err on the side of overestimating the exposure or risk. For example, a worst case assumption in evaluating dermal exposure to swimming pool water would be to assume that a person swims for 24h/day and is always 100% immersed. 

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