Analytical method for measurement of trichloramine

Status:

completed 12/2005

Aims:

When swimming-pool water is disinfected with chlorine, the reaction with urea excreted by pool users gives rise to trichloramine as a by-product. A limit value for this substance is already in force in France. Trichloramine is a suspected cause of disorders of the respiratory tract. At the request of the institution for statutory accident insurance and prevention in the gas, district heating and water supply sector (BGFW) and the Central Federation of Public Sector Accident Insurers (BUK), an assessment procedure was therefore to be developed for measurement of the trichloramine concentration in the air in indoor swimming baths (public baths, school swimming baths and baths in health facilities) in order to permit assessment of the potential hazards to employees.

Activities/Methods:

An ion-chromatographic analysis method was to be developed based upon a method used by the French Institut National de Recherche et de Sécurité (Métrologie des Polluants 007). Glass-fibre filters impregnated with sodium hydrogencarbonate/arsenic trioxide were employed for sampling. Chloride is formed by the reaction between trichloramine and arsenic trioxide. Interfering substances such as monochloramine and dichloramine are removed by an upstream silica gel cartridge impregnated with sulphamic acid. The chloride formed was desorbed by means of ultra-pure water and, following purification, by OnGuard-Na cartridges. Ion chromatographic analysis was performed by measurement of the conductivity.

Results:

An assessment procedure was developed for the measurement of trichloramine in workplace atmospheres. The method was developed in accordance with the requirements of DIN EN 482, "Workplace atmospheres - General requirements for the performance of procedures for the measurement of chemical agents", and its suitability assessed by test measurements in a number of swimming baths. It has been adopted as a standard method in the BGMG hazardous substances measurement system, and was published in the 36th edition of the BGIA Folder of the BG Institute for Occupational Safety and Health (BGIA).

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