Environ Monit Assess (2015)87: DOI 10.1007/s10661-015-4719-8
Predicting human exposure and risk from chlorinated indoor swimming pool: a case study Shakhawat Chowdhury
Received: 9 March 2015 / Accepted: 29 June 2015 # Springer International Publishing Switzerland 2015
Abstract This study predicted human exposure to disinfection by-products (DBPs) in a chlorinated indoor swimming pool. Human exposure was predicted through ingestion, inhalation, and dermal routes while ingestion exposure was accidental with water intake of 18–34 mL/h. The number of pool attendants and duration and frequency of swimming were in the ranges of 14–62 persons/day, 40–85 min/event, and 26–48 times/ year, respectively. Trihalomethanes (THMs) in pool water and air were 28.7–95.5 μg/L and 44.1–133.6 μg/m3, respectively, while haloacetic acids (HAAs) in pool water were 68.9–158.9 μg/L. The brominated THMs in water and air were 95.4 and 94.3 % of total THMs, respectively, while brominated HAAs were 94.4 % of total HAAs. Chronic daily intakes of THMs and HAAs were 2.16 × 10 −5 –3.14 × 10 −3 and 8.4 × 10 −8 –4.6 × 10−6 mg/kg-day, respectively. The cancer risk from three THMs and two HAAs was 2.46×10−5 with a range of 8.1 × 10 −6–5.7 × 10−5, in which THMs contributed 99.6 % of total risks. Approximately 99.3 % of risks were through inhalation and dermal routes, indicating that the ingestion route may be insignificant. The cancer risks from THMs in swimming pool were 4.06–6.64 times to the cancer risks from THMs in drinking water.
Keywords Swimming pool . Exposure to disinfection by-products . Cancer risks . Brominated DBPs
S. Chowdhury (*) Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia e-mail: [email protected]
Introduction Chlorine is frequently used in swimming pools to prevent outbreaks of infectious diseases. While chlorine inactivate pathogens in swimming pools, reactions with natural organic matter (NOM), bromide/iodide and human inputs (e.g., constituents of sweat and urine, skin particles, hair, microorganisms, cosmetics, and other personal care products) form disinfection by-products (DBPs) (Weisel et al. 2009). The swimming pools generally have higher temperature leading to higher rates of chlorine decay. To compensate for the chlorine demand, swimming pools use relatively higher doses of chlorine to ensure free residuals (Richardson et al. 2010). Higher free residual chlorine (FRC), higher temperature, constant organic loads, and air and water recirculation can affect DBP formation in swimming pool. To date, more than 100 DBPs have been identified in swimming pools (Richardson et al. 2010). These include trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), iodo-THMs, halonitromethanes, bromate, nitrosamines, chloramines, nitro-phenol, and 3chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and MX homologues. The most prevalent DBPs in swimming pools are chloramines, THMs, and HAAs (Chu and Nieuwenhuijsen 2002; Kim et al. 2002). Chloramines are also a group of disinfectants, which may form some DBPs (e.g., iodinated DBPs, Nnitrosodimethylamine [NDMA]). Given the high nitrogen content of organic matter from bathers, nitrogenous DBPs such as HANs and nitrosamines (e.g., NDMA) can also be formed. In addition, elevated levels of ammonia in urine react with chlorine and form chloramines, which are also found at high concentrations in swimming pools
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(Zwiener et al. 2007; Walse and Mitch 2008). Many DBPs have cancer and noncancer risks to human (USEPA 2014). The brominated and nitrogenous DBPs are more cytotoxic and genotoxic than the chlorinated DBPs, which can make the pool water more genotoxic than the source water (Richardson et al. 2010; USEPA 2014). Past studies have reported the pool-water-induced DNA damage in Hep-G2 cells (comet assay) and that most of the genotoxicity was associated with lowermolecular-weight (MW) (
Predicting human exposure and risk from chlorinated indoor swimming pool: a case study Shakhawat Chowdhury
Received: 9 March 2015 / Accepted: 29 June 2015 # Springer International Publishing Switzerland 2015
Abstract This study predicted human exposure to disinfection by-products (DBPs) in a chlorinated indoor swimming pool. Human exposure was predicted through ingestion, inhalation, and dermal routes while ingestion exposure was accidental with water intake of 18–34 mL/h. The number of pool attendants and duration and frequency of swimming were in the ranges of 14–62 persons/day, 40–85 min/event, and 26–48 times/ year, respectively. Trihalomethanes (THMs) in pool water and air were 28.7–95.5 μg/L and 44.1–133.6 μg/m3, respectively, while haloacetic acids (HAAs) in pool water were 68.9–158.9 μg/L. The brominated THMs in water and air were 95.4 and 94.3 % of total THMs, respectively, while brominated HAAs were 94.4 % of total HAAs. Chronic daily intakes of THMs and HAAs were 2.16 × 10 −5 –3.14 × 10 −3 and 8.4 × 10 −8 –4.6 × 10−6 mg/kg-day, respectively. The cancer risk from three THMs and two HAAs was 2.46×10−5 with a range of 8.1 × 10 −6–5.7 × 10−5, in which THMs contributed 99.6 % of total risks. Approximately 99.3 % of risks were through inhalation and dermal routes, indicating that the ingestion route may be insignificant. The cancer risks from THMs in swimming pool were 4.06–6.64 times to the cancer risks from THMs in drinking water.
Keywords Swimming pool . Exposure to disinfection by-products . Cancer risks . Brominated DBPs
S. Chowdhury (*) Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia e-mail: [email protected]
Introduction Chlorine is frequently used in swimming pools to prevent outbreaks of infectious diseases. While chlorine inactivate pathogens in swimming pools, reactions with natural organic matter (NOM), bromide/iodide and human inputs (e.g., constituents of sweat and urine, skin particles, hair, microorganisms, cosmetics, and other personal care products) form disinfection by-products (DBPs) (Weisel et al. 2009). The swimming pools generally have higher temperature leading to higher rates of chlorine decay. To compensate for the chlorine demand, swimming pools use relatively higher doses of chlorine to ensure free residuals (Richardson et al. 2010). Higher free residual chlorine (FRC), higher temperature, constant organic loads, and air and water recirculation can affect DBP formation in swimming pool. To date, more than 100 DBPs have been identified in swimming pools (Richardson et al. 2010). These include trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), iodo-THMs, halonitromethanes, bromate, nitrosamines, chloramines, nitro-phenol, and 3chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and MX homologues. The most prevalent DBPs in swimming pools are chloramines, THMs, and HAAs (Chu and Nieuwenhuijsen 2002; Kim et al. 2002). Chloramines are also a group of disinfectants, which may form some DBPs (e.g., iodinated DBPs, Nnitrosodimethylamine [NDMA]). Given the high nitrogen content of organic matter from bathers, nitrogenous DBPs such as HANs and nitrosamines (e.g., NDMA) can also be formed. In addition, elevated levels of ammonia in urine react with chlorine and form chloramines, which are also found at high concentrations in swimming pools
502
Page 2 of 14
(Zwiener et al. 2007; Walse and Mitch 2008). Many DBPs have cancer and noncancer risks to human (USEPA 2014). The brominated and nitrogenous DBPs are more cytotoxic and genotoxic than the chlorinated DBPs, which can make the pool water more genotoxic than the source water (Richardson et al. 2010; USEPA 2014). Past studies have reported the pool-water-induced DNA damage in Hep-G2 cells (comet assay) and that most of the genotoxicity was associated with lowermolecular-weight (MW) (
