Trichloramine in swimming pools–formation and mass transfer

Urea in swimming pool waters can react with free chlorine to form chloramine, which may lead to eye and upper respiratory tract irritation, biomarker changes in the lung, and development of asthma.

“For example, urea, often found in SPWs at high concentrations, can react with free chlorine to form chloramine (Blatchley III and Cheng, 2010;Schmalz et al., 2011), which may lead to eye and upper respiratory tract irritation, biomarker changes in the lung, and development of asthma (Bernard et al., 2006;Massin et al., 1998).”

Urea concentrations in swimming pool waters have been reported in ranges from 0.01 to 4.02 mg/L across studies.

“Urea in SPWs has been reported in many literature studies, e.g., 0.01-0.11mg/L by Afifi and Blatchley III (2015), 0.50-2.12mg/L by Schmalz et al. (2011), 0.12-3.6mg/L by De Laat et al. (2011), 0.01-4.02mg/L by Blatchley III and Cheng (2010).”

Acid amides, particularly urea, ammonium ions, and α-amino acids, were efficient trichloramine precursors.

“and that acid amides, particularly urea, ammonium ions and α-amino acids were efficient trichloramine precursors (Schmalz et al., 2011).”

Nitrogenous compounds containing various functional groups and forms of bound nitrogen have been proven as efficient trichloramine precursors, particularly at acidic and neutral pH conditions.

“A large portion of these nitrogenous compounds containing various functional groups (eNH 2 , eCOOH) and forms of bound nitrogen have been proven as efficient trichloramine precursors, particularly at acidic and neutral pH conditions (Afifi and Blatchley III, 2015;Blatchley III and Cheng, 2010;De Laat et al., 2011;Lian et al., 2014;Schmalz et al., 2011).”

When the chlorine-to-nitrogen molar ratio decreases, the formation of trichloramine decreases.

“When the chlorine-to-nitrogen molar ratio decreases, the formation of trichloramine decreases (US EPA 1994; Schmalz et al. 2011;Hansen et al. 2013).”

In human A-549 cells, exposure to >30 mg/m3 trichloramine inhibited the release of both IL-6 and IL-8 due to cytotoxicity.

“Exposure >30 mg/m 3 inhibited the release of both IL-6 and IL-8 due to cytotoxicity.”

In human A-549 cells, increased IL-8 and IL-6 levels were demonstrated at >10 mg/m3 and at 20-30 mg/m3 trichloramine, respectively.

“Increased IL-8 and IL-6 levels were demonstrated >10 mg/m 3 and at 20-30 mg/m 3 , respectively.”

Indoor swimming pool air showed similar inflammatory effects in lung cells at doses <0.2 mg/m3 trichloramine.

“Corresponding investigations with indoor swimming pool air showed similar inflammatory effects in the lung cells at doses <0.2 mg/m 3 trichloramine.”

The authors concluded that additional substances present in indoor pool air contribute to the inflammatory response.

“The authors concluded that there are additional substances present in the indoor pool air that contribute to the inflammatory response (Schmalz et al. 2011).”

In human A-549 alveolar cancer cells, decreasing cell viability with increasing trichloramine concentration was observed.

“A decreasing cell viability with increasing trichloramine concentration was observed.”