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Characteristics of trihalomethane (THM) production and associated health risk assessment in swimming pool waters treated with different disinfection methods

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... In Korea, chlorine alone, the combined use of ozone and chlorine (ozone/ chlorine), and a technique that uses electrochemically generated mixed oxidants (EGMOs), are three most commonly used disinfection methods. Ozone/chlorine seems to be the most chemical-safe method in terms of the formation of THMs, HAAs, HANs and chloral hydrate (Lee et al., 2009;Lee et al., 2010). The geometric mean concentrations of THMs in indoor SPWs were 32.9 ± 2.4, 23.3 ± 2.2, and 58.2 ± 1.7 μg/L for chlorine (n = 72), ozone/chlorine (n = 86) and EGMO (n = 25), respectively (Lee et al., 2009). ...
... Ozone/chlorine seems to be the most chemical-safe method in terms of the formation of THMs, HAAs, HANs and chloral hydrate (Lee et al., 2009;Lee et al., 2010). The geometric mean concentrations of THMs in indoor SPWs were 32.9 ± 2.4, 23.3 ± 2.2, and 58.2 ± 1.7 μg/L for chlorine (n = 72), ozone/chlorine (n = 86) and EGMO (n = 25), respectively (Lee et al., 2009). Ozone as a partial substitute of chlorine reduced the total chorine dosage therefore reduced the formation of Cl-DBPs. ...
... Panyakapo et al. (2008) assessed the cancer risk of swimmers exposed to THM-contaminated SPWs as 7.99 × 10 −4 in average which exceeds the acceptable level based on U.S. EPA standard, while only 2.19 × 10 −5 for non-swimmers. Lee et al. (2009) assessed the lifetime cancer risk via THM inhalation during swimming in a range of 7.77 × 10 −4 to 1.36 × 10 −3 based on a study of 183 indoor swimming pools in Korea. The cancer risk via THM exposure was attributed mainly by swimming activities (~94.2%), ...
Article
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The microbial safety of swimming pool waters (SPWs) becomes increasingly important with the popularity of swimming activities. Disinfection aiming at killing microbes in SPWs produces disinfection by-products (DBPs), which has attracted considerable public attentions due to their high frequency of occurrence, considerable concentrations and potent toxicity. We reviewed the latest research progress within the last four decades on the regulation, formation, exposure, and treatment of DBPs in the context of SPWs. This paper specifically discussed DBP regulations in different regions, formation mechanisms related with disinfectants, precursors and other various conditions, human exposure assessment reflected by biomarkers or epidemiological evidence, and the control and treatment of DBPs. Compared to drinking water with natural organic matter as the main organic precursor of DBPs, the additional human inputs (i.e., body fluids and personal care products) to SPWs make the water matrix more complicated and lead to the formation of more types and greater concentrations of DBPs. Dermal absorption and inhalation are two main exposure pathways for trihalomethanes while ingestion for haloacetic acids, reflected by DBP occurrence in human matrices including exhaled air, urine, blood, and plasma. Studies show that membrane filtration, advanced oxidation processes, biodegradation, thermal degradation, chemical reduction, and some hybrid processes are the potential DBP treatment technologies. The removal efficiency, possible mechanisms and future challenges of these DBP treatment methods are summarized in this review, which may facilitate their full-scale applications and provide potential directions for further research extension.
... The study of DBPs' in water took the interest of the researchers for their carcinogenicity and adverse health effects. [1,[8][9][10][11]. Various classes of DBPs' compounds include: Trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs) and haloketones (HKs). ...
... DBPs in drinking water have positive association with cancer and potential adverse reproductive effects. Numerous studies found that DBPs that have been associated with several adverse health effects from long-term exposure, including bladder and colorectal cancer and adverse birth outcomes [8][9][10]16]. Few studies have been investigated the relationship between chlorination of drinking water and cancer mortality through toxicological laboratory studies [19][20][21][22]. ...
... Few studies have been investigated the relationship between chlorination of drinking water and cancer mortality through toxicological laboratory studies [19][20][21][22]. A linkage between exposure to chlorinated drinking water and the development of urinary bladder cancer is detected [9,10,21]. Moreover, kidney, liver and intestinal tumorigenesis are also found to be associated with chronic ingestion of THMs [22,23]. ...
Article
This study predicts the possible occurrence of trihalomethanes (THMs) in water supply of Chattrogram city in Bangladesh, and life time cancer risk from multi-pathway intakes of the trihalomethanes (THMs) to the city dwellers. A total of 11 water samples were collected from the distribution network of the city, and few water quality parameters were analyzed in the study. Three empirical models developed by Amy et al. (1998), Rathbun (1996), and Malcolm Pirnie (1993) were used to estimate the level of THMs from measured water quality data, and were denoted as MODEL1, MODEL2 and MODEL3, respectively in the study. Lifetime cancer risk was estimated using predicted chronic daily intakes (CDI) of THMs' species for different exposure routes (ingestion, inhalation and dermal). The total concentrations of THMs ranged between 20 and 440 μg/L, 95–215 μg/L and 162–249 μg/L were predicted by MODEL1, MODEL2 and MODEL3, respectively. An average lifetime cancer risk was predicted as 1.4 × 10⁻⁴, 1.1 × 10⁻⁴ and 2.9 × 10⁻⁴ for oral, inhalation and dermal exposure, respectively from the water supply of the city. Percent contribution to total lifetime cancer risk were predicted as 50, 40 and10 for oral ingestion, inhalation and dermal absorption, respectively. The study revealed that lifetime cancer risk values were higher than minimum risk level set by United States Environmental Protection Agency. The findings of possible occurrence of THMs in the water supply and associated cancer risk might be beneficial as baseline data for further investigation, and help the decision makers regarding the formulation of standards and legislations of THMs.
... The residual concentration of chlorine prevents the consequent pollutions after treated water enters the distribution system [5]. However, when chlorine reacts with natural organic matters (NOMs) existing in water as precursor, a numerous chlorinated disinfection by-products (DBPs) will be produced including thrihalomethanes (THMs) such as [3,4,[6][7][8][9]. The THMs have been proven to be potentially genotoxic and mutagenic for human and can cause bladder cancer, spontaneous abortions, colonrectum and brain cancers in the case of long-term exposure [3,5,10,11]. ...
... As shown in Table 5, the mean value of lifetime cancer risks of THMs for residents through inhalation is 6.46×10-7, which is lower than the minimum or negligible level set by US.EPA (1.0 × 10 −6 ) [26]. The LTCR calculated in the present research for inhalation of THMs is lower than findings resulted in different areas such as Seoul, Korea (7.35 × 10 − 5 ) [6] and I s l a m a b a d , P a k i s t a n ( 1 . 2 4 × 1 0 − 4 ) [1 ] . ...
... The LTCR calculated in this study for dermal contact seems to be higher than the results from studies in other areas of Iran [14]. The LTCR calculated for dermal contact was different in Seoul, Korea (3.63 × 10 −6 ) [6],Tehran (1.19 × 10 −7 ) [14] and Islamabad, Pakistan (2.0 × 10 −4 ) [22]. The result of present study showed that The LTCR calculated for dermal contact was higher than Tehran (1.19×10-7) (15). ...
Article
Trihalomethanes (THMs) have been proven to be potentially genotoxic and mutagenic for human. The aim of this study was to characterize the THMs spatiotemporal distribution and its carcinogenic risk potential in Ardabil water distribution system. Water samples were collected over consecutive months from twenty-six points in the city of Ardabil from April 2016 to March 2017. The potential carcinogenic risk assessment of THMs was evaluated quantitatively with uncertainty assessment based on Monte-Carlo simulation technique. The results showed that the mean concentrations of bromodichloromethane, Chloroform, dibromochloromethane and Bromoform in water consumed by residents were 101.97 ± 58.51, 85.18 ± 47.79, 51.67 ± 29.57 and 11.89 ± 6.64 μg/L, respectively, during the sampling period. According to the result of this study, the concentrations of THMs were higher in summer in comparison with other seasons. The mean values of lifetime cancer risks for residents through ingestion, inhalation and dermal contact are 2.85×10-4, 6.46×10-7, and 1.26×10-7, respectively. The lifetime cancer risks for residents through ingestion was found to be 285 times more than the minimum or negligible level set by US.EPA (1.0×10-6) and for dermal contact and inhalation lower than the minimum or negligible level set by US.EPA. The results of the present research may contribute to inform the decision makers of drinking water supply system about the role of water quality in the health of consumers.
... Different tests indicate the necessity for the proper ventilation of a swimming pool, but the authors did not provide any details on how exactly the proper ventilation should look like [9,12,24]. These suggestions are the results of the awareness regarding the ways DBPs penetrate the human body, among which inhalation plays the most important part. ...
... There is much scientific research regarding the presence of DBPs in swimming pools when applying different methods of water disinfection [24,33]. Often, this is focused on a comparison of the concentration of these compounds in the water and air when different methods of disinfection are applied. ...
... . Limiting Impact of DBPs on Users' Health3.1. Limiting DBPs PrecursorsAccording to the literature, as the high concentration of DBPs in the water and air results from the high number of the precursors[23,24], it can be assumed that a limitation of the organic compounds in the pool's water introduced by the users ...
Article
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The presence of water disinfection by-products (DBPs) in the pool environment is a threat to the health of the users of swimming pools. Due to the mechanism of DBP formation, we are not able to prevent their presence. However, there are several ways to prevent the harmful effects of DBPs on the health of pool users; among these, various kinds of methods that result in the reduction of combined chlorine and DBPs precursors should be mentioned. And last but not least, a new approach to the design of the ventilation system for indoor swimming pools seems to be crucial for the above-mentioned purpose.
... Unfortunately, disinfectants can react with many components (e.g., natural organic matter, bromide, and iodide), thereby resulting in the formation of disinfection byproducts (DBPs) (Chowdhury et al., 2014;Ersan et al., 2019;Hang et al., 2016;Yang et al., 2016). Toxicological studies have revealed that many DBPs are carcinogenic and teratogenic, and epidemiological studies have shown that several health issues are associated with exposure to DBPs, such as reproductive health effects, asthma, and bladder cancer (Carter and Joll, 2017;Chen et al., 2011;Font-Ribera et al., 2016;Lee et al., 2009). In a recent study, Font-Ribera et al. (2019) reported moderate associations with micronuclei in reticulocytes and DBP exposure while swimming in a chlorinated pool. ...
... The risk posed by DBPs in swimming pools have been revealed by previous studies (Gouveia et al., 2019;Yang et al., 2018a;Hang et al., 2016;Chowdhury, 2015;Chen et al., 2011;Lee et al., 2009;Panyakapo et al., 2008). Panyakapo et al. (2008) calculated the cancer risks from the highest and average concentrations of THMs in swimming pools in Thailand (1.38 × 10 −3 and 7.53 × 10 −4 , respectively). ...
... For women, the mean total risk was slightly higher than that for men owing to the differences in skin surface area and body weight. In indoor swimming pools, inhalation risks of THMs provided a higher contribution to the total cancer risk, which was consistent with the conclusions reported by other published articles (Gouveia et al., 2019;Hang et al., 2016;Chen et al., 2011;Lee et al., 2009). Lee et al. (2009) found that the lifetime cancer risks posed by THMs from oral ingestion and dermal exposure are mostly less than 10 −6 , and swimmers are at a higher risk of inhalation exposure (7.77 × 10 −4 -1.36 × 10 −3 ). ...
Article
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Disinfection is an indispensable water treatment process used to inactivate pathogens and prevent outbreaks of infectious diseases in swimming pools. However, toxic disinfection byproducts (DBPs) are inevitably formed during the process. To improve the supervision and regulation of DBPs in swimming pools, the reliability of using trihalomethanes (THMs) as the sole indicator of organic DBPs and the possibility of using easily detectable water quality parameters as predictors of DBPs were discussed based on the occurrence of 29 typical DBPs in swimming pools. Among the target DBP categories, THMs and haloacetic acids (HAAs) were the prominent species, and the concentrations of HAAs were the highest. The risk assessment results indicated that the total risk values in most pools were higher than the acceptable value (10⁻⁶). Compared with nitrosamines and THMs, HAAs were the main contributors to the cancer risks posed by dermal absorption and ingestion. THMs (r = 0.619; p < 0.01) and HAAs (r = 0.989; p < 0.01) were both significantly correlated with total DBPs (the sum of 29 DBPs). A stepwise multivariate regression model was developed by analyzing the correlations between total DBPs and water quality parameters, and the relationship coefficient R² was 0.756. This study provides important information and perspectives for the improvement and implementation of standards for swimming pool water.
... Various researchers had carried out studies to assess the THM concentrations in different types of waters (Budziak and Carasek 2007;Pavón et al. 2008;Al-Omari et al. 2005). THMs in indoor swimming pool water has reported in various countries like United States, Spain, Korea, UK, Italy, Germany, Thailand, Poland, Taiwan, and Iran (Amer Kanan 2010; Santa Marina et al. 2009;Lee et al. 2009;Chu & Nieuwenhuijsen 2002;Fantuzzi et al. 2001;Erdinger et al. 2004;Panyakapo et al. 2008;Hsu et al. 2009;Kozłowska et al. 2006;Heydari et al. 2013). In most of the studies, pool water uses Cl 2 as the disinfectant. ...
... The study on carcinogenic and non-carcinogenic effects of THMs in swimming pools is essential in public health. Few studies reported higher health risk using different measurements and indicators such as lifetime cancer risk, Hazard Index (HI), genotoxic risk, etc. (Tokmak et al. 2004;Lee et al. 2009;Jesonkova and Bozek 2013;Peng et al. 2020;Felgueiras et al. 2020). A study was reported that THMs levels in post showered blood samples were highly correlated with CF in water and air by inhalation (Silva et al. 2012). ...
... LCR was mainly from exposure to CF by inhalation found to be higher than 10 -6 in all the pools for both male and female swimmers. In contrast, exposure to the other components of THMs by ingestion and dermal observes to be negligible (Lee et al. 2009). From the LCR Inh calculations in the pool-2 swimmers will be impacted by all components of THM on continuous exposure, while pool-3 and 8 swimmers will be affected by CF and DBCM and similarly pool-7 by CF and BF. ...
Article
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Tri halo methanes (THMs), a common disinfection by products in swimming pool water are the major concern in Kuwait. With the objective of assuring the safety and health of the swimmers, the study was focused on THMs in indoor pool samples collected from mid-July to October 2018. pH, temperature, residual chlorine, and total organic carbon were analyzed in relation to THMs. The concentration ranged from 1.9 to 85.7 µg/L in all pools, and the values were within the specification limits on an average for each pool. A few significant correlations were established between Tri halo methane components from statistical analysis. Since long-term exposure of Tri halo methanes affect swimmer's health, the total lifetime cancer risk index was calculated and observed that all the pools had a value greater than 10–6, including both male and female swimmers. The main contribution of risk identified from the study was chloroform exposure through inhalation. Also, the non-carcinogenic effect on swimmers using hazard index was estimated and determined that few pools exceeded the value1.0. The average total lifetime cancer risk of all pools for men and women (8.03 × 10−6 and 8.8 × 10−6 ), hazard index for men and women (1.31 and 1.43) were above guidelines and classified as risk. Therefore, the pools should be monitored and maintained with care to reduce the concentration of disinfectant used and subsequently lowers the generation of THMs. The frequent cleaning of pools will help to continue swimming without any long term exposure effects.
... Pool water treatment also plays a factor and affects air and water quality [19]. Some research focused on changes in the water treatment system by introducing modifications such as a column with the activated carbon or with an ion-exchange deposit; this research indicated that the exchange of water led to a decrease of DBP concentrations [24][25][26][27]. ...
... Through accumulation in the cells of living organisms, they have carcinogenic, mutagenic, and teratogenic effects. These compounds can cause: asthma [24,[31][32][33], upper respiratory problems [32,34,35], eye and skin irritation [6,32], cancer [36], including bladder cancer [37][38][39], and even infertility [40,41]. ...
... Due to this, a straightforward and economical solution to help combat increased DBP concentrations was sought. Reducing DBP levels in pool water include introducing changes in the water treatment system [19,24,26,27]. The positive impact of the total pool water exchange is also indicated, thanks to which the impurities accumulated in the water are removed [27]. ...
Article
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Pool water must be constantly disinfected. Chlorine compounds used to disinfect pools react with organic substances such as sweat, urine, and personal care products introduced into pool water by users and results in the formation of disinfection byproducts. Trihalomethanes (THM), including chloroform and dissolved organic carbon (DOC) concentrations, were quantified using a two-stage process: determining initial THM and chloroform levels; then searching for a cheap and easy-to-use method to improve water quality. The method proposed here to limit THM and DOC concentrations in water is controlled showering. At three swimming pool facilities, chloroform concentrations (13.8 ± 0.33 µg/L, 15.5 ± 0.44 µg/L, and 13.9 ± 0.06 µg/L) were below the threshold concentration of 30 µg/L. At a fourth facility, however, the chloroform concentration exceeded that threshold (40.7 ± 9.68 µg/L) when showering was not controlled. Those conditions improved after the introduction of a mandatory shower; concentrations of DOC, THMs, and chloroform all decreased. The chloroform concentration decreased to 29.4 ± 3.8 µg/L, the THM concentration was 31.3 ± 3.9 µg/L, and the DOC concentration was 6.09 ± 0.05 mg/L. Pilot tests were carried out at real facilities to determine whether the control of pre-swim hygiene was possible. The introduction of proper pre-swim hygiene limited the concentration of DOC in water and can lead to a healthier environment for everyone attending the swimming facility.
... This study aimed to determine the concentration of chloroform as an indicator of THMs in the swimming pool of Shiraz University of Medical Sciences and estimate human health risk for the swimmers. The previous studies revealed high concentrations of THMs in swimming pools, with chloroform (CHCl 3 ) being the predominant species (Lee et al., 2009;Erdinger et al., 2004;Weaver et al., 2009;Simard et al., 2013). ...
... This might be associated with the simultaneous use of chlorination and ozonation for disinfecting the pool. Lee and Blahley (Lee et al., 2009) also reported that the chloroform concentration ranged from 70 to 140 μg/l in three chlorinated pools based on a small data set (Li and Blatchley, 2007). ...
... The value of which was equals 35.93μ which is a small amount and won't cause a significant problem through exposure to chloroform. A study by Lee et al. (2009); Which was performed to estimate exposure to trihalomethanes indoors in a swimming pool, showed that the highest exposure was through inhalation. While risks from dermal exposure and oral ingestion to THMs were the negligible risk level defined by the USEPA (<1μ) (Lee et al., 2009). ...
Article
This cross-sectional study aimed to examine the concentration of the by-products of chlorination in the swimming pool and estimate human health risk for the swimmers of Shiraz University of Medical Sciences. In this study, the chloroform concentrations of 16 samples were measured using Gas Chromatography (GC). All the measured concentrations were less than the allowed amount announced by the World Health Organization (WHO). The results of the cancer risk (CR) and hazard index (HI) showed that the major exposure routes were found to be dermal during swimming and the 95 percentile of estimated CR and HI for the male group were 1.38 × 10⁻¹⁰ and 1.82 × 10⁻⁵ respectively, which is higher than the values of 5.48 × 10⁻¹⁰ and 2.25 × 10⁻⁵ respectively, for the women group. Sensitivity analyses indicated that the swimming exposure time (ET), and chloroform concentration were the most relevant variables in the health risk model. Therefore, knowledge about the sources of micro-pollutants in swimming pools might help promote the health methods of the pool environment.
... Temperature ranged from 31°C to 33.4°C. Both these values fall under the prescribed WHO guideline limits [62], and are similar to those reported in other research investigations [34,39,45]. Residual chlorine content of the samples varied from 0.0703 to 0.1418 Cl 2 mL −1 , which appeared to be quite low to achieve proper disinfection of swimming pool water. ...
... High level of observed THMs may be attributed to the presence of high level of NOM content in pool water [37]. A comparative study revealed that observed THMs levels were higher than those reported in countries like Korea [34], Italy [2], UK [15], Canada [45], Germany [33] and Spain [9]. As mentioned above, Henry's law was used to estimate the concentration of THMs in air. ...
... Inhalation exposure risk values were approximately three times higher than the acceptable risk level (10 −6 ) thus indicating significant risk and possible concerns on human health. Previous studies also reported inhalation to be the major route of exposure [18,34]. Few studies, though, suggest dermal exposure to be the most significant pathway [13]. ...
Article
Disinfection is an important process to make the water free from harmful pathogenic substances, but sometimes it results in the formation of harmful by-products. Development of predictive models is required to define the concentration of THMs in pool water. Majority of studies reported inhalation to be the most significant THMs exposure route which is more likely to be dependent upon the concentration of THMs in pool water and in air. THMs concentration in the analyzed pool water samples and in air was found to be 197.18 ± 16.31 μg L−1 and 0.033 μgm3–1, respectively. Statistical parameters such as high correlation coefficients, high R2 values, low standard error, and low mean square error of prediction indicated the validity of MLR based linear model over non-linear model. Therefore, linear model can be most suitably used to pre-assess and predict the THMs levels in swimming pool water. Risk estimation studies was conducted by using the united states environmental protection agency (USEPA) Swimmer Exposure Assessment Model (SWIMODEL). The lifetime time cancer risk values related to chloroform exceeded 10−6 for both the sub-population. Inhalation exposure leads to maximum risk and contributed up to 99% to total cancer risk. Risk due to other exposure pathways like accidental ingestion and skin contact was found to be negligible and insignificant. Monte Carlo simulation results revealed that the simulated THMs risk values for the studied exposure pathways lies within ±3.1% of the average risk values obtained using SWIMODEL. Hence, the risk estimates obtained using SWIMODEL seemed to be appropriate in determining the potential risk exposure of THMs on human health. Variation in input parameters like body weight (BW) and skin surface area (SA) leads to difference in risk estimates for the studied population. Non cancer riskwas found to be insignificant as represented by low hazard quotient (HQ < 1) values. Through monitoring and regulations on control of THMs in swimming pool water is required to minimize the risk associated.
... Chlorine is inexpensive and relatively convenient to produce, store, transport, and apply. It provides rapid and long-lasting bactericidal effects but is limited mainly because of the formation of potentially toxic DBPs, such as trihalomethanes, halomethanes (THMs), haloacetic acids, halonitromethanes, haloacetonitriles, chloramines, and chlorophenols [22,25,65,[72][73][74][75][76][77][78][79][80]. For example, the levels of potentially toxic DBPs tend to be higher in hot tubs, due to recirculation and smaller volumes but also because acceptable thresholds tend to be more elevated than in swimming pools [73][74][75]. ...
... Moreover, due the chemical characteristics of thermal water, the reaction between chemical compound and disinfection agents can lead the increase the potentially toxic DBPs. [22,25,65,[72][73][74][75][76][77][78][79][80] Ozone Highly effective, no smell. Can reduced the formation of potentially toxic disinfection by-products (DBPs). ...
Article
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Natural spa springs are diffused all over the world and their use in pools is known since ancient times. This review underlines the cultural and social spa context focusing on hygiene issues, public health guidelines and emerging concerns regarding water management in wellness or recreational settings. The question of the “untouchability” of therapeutic natural waters and their incompatibility with traditional disinfection processes is addressed considering the demand for effective treatments that would respect the natural properties. Available strategies and innovative treatments are reviewed, highlighting potentials and limits for a sustainable management. Alternative approaches comprise nanotechnologies, photocatalysis systems, advanced filtration. State of the art and promising perspectives are reported considering the chemical-physical component and the biological natural complexity of the spa water microbiota.
... Long-term health effects, such as adverse reproductive outcomes, cancer, and stillbirth, have been associated with exposure (World Health Organization, 2017;Rivera-Núñez et al., 2018). In some studies, in which multi-pathway exposures have been estimated, the cancer risk of exposure to THMs in indoor swimming pool facilities is found to be unacceptably high compared with the upper limit of the acceptable cancer risk proposed by the European Commission (10 −5 ) (European Commission, 2009;Lee et al., 2009;Chen et al., 2011). Some European countries have established exposure limit values for tTHM in swimming pool water, ranging from 20 to 100 μg l −1 (ANSES, 2010;Ohlsson et al., 2014;Rijksinstituut voor Volksgezondheid en Milieu, 2014). ...
... Identifying the determinants of exposure is essential in the control of exposure but also for a valid and precise assignment of exposure levels (Rappaport and Kupper, 2008). Although the occurrence and exposure to tTHMs in swimming pools have been investigated in several previous studies (Lee et al., 2009;Westerlund et al., 2016;Boudenne et al., 2017), the determinants causing the concentration to vary within and between sampling locations have not received attention and no systematic sampling strategy to collect representative air samples has so far been proposed. The aim of this study is to determine the size and magnitude of the variability and to analyse which determinants affect the exposure within three pool facilities in order to be able to optimize a sampling strategy for tTHM. ...
Article
Introduction Negative health effects related to long-term exposure to volatile trihalomethanes (THMs) formed during the chlorination of pool water is recognized, but the determinants causing the concentrations to vary within and between sampling locations have not received much attention. Methods One hundred and twenty air samples of four THMs were examined in three Norwegian indoor pool facilities. In each facility, repeated samples were collected above a sports pool and a therapy pool, 0.05 and 0.60 m above the water’s surface. A linear mixed model (LMM) was used to identify determinants of exposure and the variability in THM concentration within and between sampling locations, days, and heights in pool facilities. Results The within variability of days, sampling locations, and heights was greater than between days, sampling locations, and heights. Determinants contributing significantly to the exposure were pool facility, height, swimming pool, day of the week, time during the day, and number of bathers. These findings limits how exposure categories should be defined to be able to identify the real long-term exposure and to propose suitable exposure limit values. Discussion These determinants could help future research be designed with effective sampling strategies and to collect information about the real long-term exposure, which is important in terms of establishing a dose–response relationship and exposure limit values. Conclusions If unbiased exposure assessments are to be conducted among the different users of the pool facility, air samples should be collected over time and for different exposure scenarios.
... The International Agency for Research on Cancer (IARC), the cancer research agency of WHO, and USEPA's Integrated Risk Information System (IRIS) classify THM (chloroform, CDBM, DCBM and bromoform) as possible or probable human carcinogens based upon sufficient evidence of carcinogenicity in animals (IARC, International Agency for Research on Cancer 2018; USEPA, U. S. Environmental Protection Agency 1987). Based upon these classifications, and similar to earlier studies (Chen et al. 2011;Chowdhury 2015;Lee, Ha, and Zoh 2009), multi-pathway risk assessment models were employed to predict the risk that exposure to THM may represent for study participants. For swimmers, for which a multi-pathway assessment model is applicable, the THM exposure through inhalation was found to be the major contributor to lifetime cancer risk. ...
... Subsequently, values obtained for representing cancer risk due to exposure to THM via oral and dermal routes were noted to provide a low contribution for the cumulative cancer risk. Previously, various investigators also reported that inhalation provided the highest % contribution to the total cancer risk associated to THM exposure in swimming pools (Chen et al. 2011;Hang et al. 2016;Lee, Ha, and Zoh 2009). Nevertheless, other studies demonstrated that the dermal route was more relevant (Chowdhury 2015). ...
Article
Disinfection by-products (DBP) such as trihalomethanes (THM) are formed when chlorine and bromine interact with natural organic materials in chlorine-treated swimming pools. Epidemiological evidence demonstrated an association between exposure to swimming pool environment and adverse health effects. Therefore, this study aimed to assess carcinogenic and non-carcinogenic risk of long-term exposure of elite swimmers and their coaches. In an Olympic-size indoor chlorinated swimming pool, THM levels were determined in water (21–69 µg/L), in the boundary layer above the water surface (59–397 µg/m³), and in the air surrounding the pool (28–390 µg/m³). These values were used to predict multi-pathway chronic daily intake (CDI), cancer risk (CR) and hazard index (HI). Oral and dermal CDI for swimmers were 2.4 × 10⁻⁶ and 2.0 × 10⁻⁸, respectively. The swimmers’ inhalation CDI (1.9 × 10⁻³ mg/kg/day) was estimated to be sixfold higher than levels obtained for coaches (3.3 × 10⁻⁴ mg/kg/day). According to guidelines, the HI was acceptable, but CR exceeded the recommended limit for both, coaches (CR: 5.5 × 10⁻⁷–8.5 × 10⁻⁵; HI: 6.5 × 10⁻⁴–1 × 10⁻¹) and swimmers (CR: 1.4 × 10⁻⁵–3.6 × 10⁻⁴ HI: 1.6 × 10⁻²–4.3 × 10⁻¹). Our findings provide further support to the need to develop comprehensive guidelines to safeguard the health of individuals involved in elite swimming.
... A class of DBPs called chloramines which includes trichloramine (a gas that gives indoor pools their typical smell) has been found to be unstable in water and able to easily penetrate the lower airways of swimmers (Schmalz et al, 2011). Trihalomethanes (THMs), another class of DBPs which has been found to be carcinogenic in rodents , have been detected in pool water and found to be seven times higher in the blood and exhaled breaths of swimmers after swimming in indoor pools (Lee & Zoh, 2009). More time spent swimming in chlorinated swimming pools was associated with increased THM concentrations . ...
... The positive health gains from swimming might be increased by reducing the potential health risks of the pool water caused by DBPs and other chemicals that lead to respiratory discomfort and could also be potentially mutagenic. Research findings recommended increasing air circulation in indoor pool settings to reduce the concentrations of DBPs as well as choosing a suitable disinfection method (Lee & Zoh, 2009); however, it is difficult to define "suitable" as studies are lacking directly comparing the DBPs generated by the wide variety of disinfectants currently used alone and in combination, including salt water electrolysis, chlorine, bromine, and ozone. Currently, apart from Germany and Denmark, few specific guidelines appear to exist worldwide or in the U.S. for the concentrations of DBPs in the swimming pool environment (Carter & Joll, 2017). ...
... The most dangerous is the effects of DBPs, which isare not noticed in many years of regular bathing. Asthma, bladder cancer, and atopic dermatitis are being increasingly recognized as risks to the health of pool users and facility employees [2,4,39,40]. It has also been confirmed that microcontaminants produced as DBPs of various enzymes, produced as DBPs, lead to the generation of oxidative stress in the cells of living organisms [41]. ...
Article
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The washings remaining after rinsing the pressure filters in swimming pool facilities constitute a stream representing the full array of impurities found in these waters. To separate individual frac-tions of these impurities, pressure membrane processes, ultra-, and nanofiltration have been used. The washings from water circuits in pools of different intended use and with various impurities were analyzed. Six fractions were obtained, with an apparent molar mass of: >200; <200; 200–30; <30kDa; 30kDa–300Da; <300Da. The quality of each fraction was evaluated in terms of physicochemical characteristics – concentration of total organic carbon (TOC), absorbable organic halogens (AOX) – and ecotoxicological characteristics (Microtox®, Artemia salina). The distribution of the impuri-ties in individual fractions varied. The highest concentrations of impurities were observed in the washings from the swimming pool, in the >200kDa fraction, 7.87, and 2.85mgCl/L. However, in the fraction below 300Da, TOC and AOX concentrations reached 0.93 and 0.47mgCl/L, respec-tively. Itshould be noted that all analyzed samples of impurity fractions were characterized by low/nontoxicity. There was no correlation between selected physicochemical parameters, or the concentration of TOC and AOX, and the toxicity level
... Several DOM properties are closely related to the occurrence of DBP precursors (such as THMs), and/or can be used as descriptors for predicting their FPs. This includes DOM's spectroscopic properties (i.e., ultraviolet absorbance at l ¼ 254 nm or SUVA 254 (Hua et al., 2015) and fluorescent signal (Roccaro et al., 2009)), its composition (e.g., the presence of protein-like organic matter (Chu et al., 2010), aromatic moieties (Hua et al., 2015), and suspended particulate matter (Hou et al., 2018)), and the bulk concentration of DOM, which can be accounted as total organic carbon, TOC (Lee et al., 2009), or as dissolved organic carbon, DOC (Peng et al., 2016). ...
Article
In order to understand and minimize the formation of halogenated disinfection by-products (DBPs), it is important to investigate how dissolved organic matter (DOM) contributes to their generation. In the present study, we analysed the DOM profile of water samples from the Barcelona catchment area by high resolution mass spectrometry (HRMS) and we studied the changes after chlorination. Chlorination produced significant changes in the DOM, decreased the average m/z and Kendrick mass defect (KMD) of their spectra and decreased the number and abundance of lignin-like features. The Van Krevelen (VK) fingerprint exhibited several noticeable changes, including the appearance of highly oxidized peaks in the tannin-like region (average O/C, 0.78 ± 0.08), the appearance of features with low H/C and the disappearance of more than half of the lipids-like features. Up to 657 halogenated peaks were generated during sample chlorination, most of which in the condensed hydrocarbons-like and the lignin-like region of the VK diagram. Around 200 features were found to be strongly correlated (ρ ≥ 0.795) to the formation potential of trihalomethanes (THMs) and 5 were correlated with the formation potential of haloacetonitrile (HANs). They all were plotted in the lignin fraction of the VK diagram, but both groups of features exhibited different nitrogen content: those features related to HANs FP had at least one nitrogen atoms in their structures, whilst those related to THMs did not.
... The values of TOC and DOC concentrations are commonly analyzed parameters of pool water quality. The TOC values presented in the literature show large variations, depending on a load of objects and the applied water treatment purification technology, they range from 0.70 to even 85 mgC/L [3,[21][22][23]. It can be assumed that all values obtained in this study did not differ from the literature data (range from 0.71 to 11.00 mgC/L). ...
Conference Paper
Full-text available
The aim of the study is to determine the fractional share of organic pollutants in washings samples, collected after pressure filters washing. The evaluation of the physicochemical and toxicological quality of raw washings, fraction <200 kDa, <30 kDa and <300 Da has been presented. Separation of selected fractions was carried out with the participation of a multistage pressure membrane system using ultra-and nanofiltration. The physicochemical analysis was conducted based on the total organic carbon (TOC) concentration, dissolved organic carbon, and total carbon. The toxicological classification of isolated fractions was also prepared using the percentage of toxicity effects obtained in commercial bioassays-Microtox ® and Artoxkit M. The concentration of TOC in the analyzed samples of raw washings was ranged from 2.50 to 11.00 mgC / L. The presented study showed a significant share of the organic pollutants fraction with a molar weight below 300 Da in the examined washings (the TOC was from 0.71 to 1.48 mgC/L). No correlation was observed between the concentration of TOC and the percentage of toxic effect. Screening toxicity tests can be a signal of swimming pool water quality; but they need to be extended with additional test organisms or observations of more morphological parameters of these organisms.
... An HAA concentration of~8000 mg/L in an indoor pool has been reported, indicating that non-volatile HAAs can easily accumulate in a swimming pool. Lee et al. (2009) collected and analyzed water samples from 183 indoor swimming pools in Seoul, Korea which were treated with different disinfectants. The results showed that the geometric mean concentrations of total THM in the swimming pool waters were 32.9 ± 2.4 mg/L with chlorine, 23.3 ± 2.2 mg/L with ozone/ chlorine, and 58.2 ± 1.7 mg/L with electrochemically generated mixed oxidants. ...
Article
In this study, a bench-scale system was utilized to assess the disinfection byproduct (DBP) formation from human endogenous organic matter. Perspiration and urine, constituting the main organic substances in swimming pools, were selected to represent the major human endogenous organics. Results revealed that the continuous input of body fluids into the reactor led to rapid accumulation of endogenous organic matter, which contributed to high concentrations of DBPs in the swimming pool. The increase in nonpurgeable organic carbon (NPDOC) concentration from the perspiration precursor was lower than that from urine during the operation. Moreover, the accumulation of swimmers' body fluids leads to increased DBP precursors, as well as increased chlorine demand and DBP formation in swimming pool water. The concentration of the trihalomethanes (THMs) and haloacetic acids (HAAs) consistently increased during the reaction. More THMs were generated in urine solution, whereas more HAAs were found in perspiration solution. To improve the water quality in swimming pools, ozonation, UV/Chlorine, and UV/H 2 O 2 treatments were evaluated for their efficacy in reducing the DBP precursors. Results revealed that all of the three treatment processes can degrade the DBP precursors in perspiration and urine, eventually decreasing the DBP concentrations. However, only the UV/H 2 O 2 treatment can decrease the formation of DBPs in perspiration and urine. In addition, the results revealed that UV/Chlorine and UV/H 2 O 2 treatments should be operated for a sufficient contact time to prevent the increased production of DBP precursors in water at the early stage of the treatment.
... On the other hand, water distribution networks, due to extended contact time between chlorine residuals and THM precursors in the system, provide suitable environments for THM formation (Al-Omari et al. 2014). Higher chlorine residuals and the presence of NOM may augment the formation of THMs (Singh et al. 2012;Lee et al. 2010). ...
Article
Full-text available
Central composite rotatable design (CCRD) was employed to optimize initial temperature (ºC), ramp function (ºC/min) and salt addition for trihalomethane extraction/quantification from the drinking water distribution network in Ratta Amral, Rawalpindi., Pakistan. Drinking water samples were collected from the treatment plant, overhead reservoir and consumer’s taps. The USEPA method for trihalomethane detection 551.1 via gas chromatography was applied using liquid–liquid extraction. The experiments with input variables for sample preparation and operational conditions were performed in a randomized order as per design of experiment by central composite rotatable design and responses were evaluated for model development. A significant ( p = 0.005) two-factor interaction model was optimized. Initial temperature was observed to be insignificant ( p = 0.64), while ramp function ( p = 0.0043) and salt addition ( p = 0.04) were significant. Product of salt addition and ramp was significant ( p = 0.004), while product of initial temperature and salt addition was insignificant ( p = 0.008). With a desirability function of 0.97, an initial temperature of 50 ºC, 6 ºC rise/min to 180 ºC and 0.5 g salt were optimized. It was found that development and optimization of the analytical methods for rapid trihalomethane detection would improve optimization of the current treatment practices in the country.
... Wang et al. also found that the cancer risks resulting from intakes of THMs are variable not only by the type of THM, but also by the route of exposure (Wang et al. 2007). Jin Lee et al. evaluated the lifetime cancer risks related with different exposure pathways by THMs in swimming pools and found that swimmers can be at the greater risk from inhalation exposure (Jin et al. 2009). THMs exposure risk to human health during non-potable reuse was estimated, and the lifetime cancer risks estimation presented that inhalation exposure to chloroform in the using peak THMFP values showed the highest cancer risks of 1.28 × 10 −6 and 1.12 × 10 −6 to residential adult and child receptors, respectively (Aina and Ahmad 2013). ...
Article
Full-text available
Trihalomethanes (THMs) and adsorbable organic halides (AOX) were generated in chlorinated water. The purpose of the study was to provide a comprehensive picture of concentration distribution, the seasonal and different water source variability of THMs and AOX. Data for THMs, AOX, and other physico-chemical parameters were from 538 samples of 16 drinking water work through a 3-year sampling program which was conducted in Shandong province with typical temperate and monsoonal climate. Selected samples were considered with the influence of factors such as season, water source, and disinfectant. The THMs and AOX concentration of the samples disinfected with chlorine ranged from 2.1–105 μg/L and 11–238 μg/L, respectively. The THMs and AOX concentration of the samples disinfected chlorine dioxide ranged from N.D.–47.6 μg/L and N.D.–102 μg/L, respectively. The median concentration of THMs and AOX of samples disinfected with chlorine were 35 μg/L and 61 μg/L, much higher than chlorine dioxide, respectively. Ninety-two percent of the samples disinfected with chlorine and all samples disinfected with chlorine dioxide met Chinese drinking water standard for THMs. The ratio of tribromethane (TBM) to THMs of samples disinfected with chlorine was 19%, lower than chlorine dioxide 42%. Bromine substitution factor (BSF) of THMs and initial concentration of bromide showed weak correlation, and the Spearman correlation coefficient was 0.38. THMs and AOX concentrations showed noticeable seasonal variations with the highest median concentrations in spring. The levels of THMs and AOX in drinking water varied with different water sources and followed the order local reservoir > Yellow River reservoir > ground water. The survey results complement the database of THMs and AOX occurrence in drinking water in China, and offer a significant reference data for setting disinfections by-products occurrence in countries or regions with similar climate around the world.
... Lee et al., 2009) Chlorine and ChloraminesPeople experienced a serious of infection after a party where they spend(Kaydos-Daniels et al., 2008) ...
Article
Water contamination through anthropogenic and industrial activities has led to the emergence and necessity of disinfection methods. Chlorine and bromine gases, often used to disinfect water, resulted in the by-product formation by reacting with organic matter. The Disinfectant by-products (DBP) led to the formation of Trihaloaceticacid (TAA), Trihalomethane (THM), and other minor components. The release of chemicals has also led to the outbreak of diseases like infertility, asthma, stillbirth, and types of cancer. There are new approaches that are found to be useful to compensate for the generation of toxic by-products and involve membrane technologies, namely reverse osmosis, ultrafiltration, and nanofiltration. This review mainly focuses on the toxicology effects of DBPs and various approaches to mitigate the same. The health hazards caused by different DBPs and the various treatment techniques available for the removal are discussed. In addition, a critical comparison of the different removal techniques was discussed.
... Najgroźniejsze jest to oddziaływanie UPD, które nie jest dostrzegane przez wiele lat regularnych kąpieli. Astma, rak pęcherza moczowego, atopowe zapalenie skóry stanowią coraz szerzej analizowane zagrożenia dla zdrowia użytkowników basenów, a także pracowników obiektów [48,50,89,90]. Potwierdzone zostało wytwarzanie przez mikrozanieczyszczenia w postaci ubocznych produktów dezynfekcji różnych enzymów, które działają w sposób wywołujący stres oksydacyjny w komórkach żywych organizmów [91]. ...
Thesis
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The pool water environment is a specific system whose quality is shaped by a number of factors related to both the purification technology and the diversity of introduced pollutants. It should be borne in mind that the water feeding the circuit circulates, to a large extent, in a closed system for many months, and only its losses are constantly replenished with fresh tap water. This type of solution allows you to reduce water consumption, but carries the risk of concentration of contaminants in circulation, including by-products of disinfection. It is necessary to verify the effectiveness of currently available pool water treatment technologies. Also, there is a need for search for new, cheap and quick methods of diagnosing ingredients that may have a detrimental effect on living organisms. The purposes of this paper involve the adaptation of the possibility to use a new way of supporting the quality control of pool water in the form of biotest, as well as presentation of the perspectives for re-use of the rinse water after rinsing the filters used in technological circuits. However, due to the complexity of the topic, the main goals have been divided into sub-objectives, including identification of basic problems of pool water quality in physico-chemical as well as toxicological terms, assessment of the possibility of reusing post-wash washings without prior purification and using processes - sedimentation, dechlorination and coagulation, and the prospects of using pressure membrane processes in purifying pool water and washing processes individual and integrated systems. The subject matter of the research were the samples of pool water collected from the pools of different destination, of selected elements of purification circuits and the rinse water collected after rinsing the filtration resources. We have also analysed samples of purified rinse water after single purification processes and from circuits integrated with membrane processes. The main problems with the quality of pool water in the analysed objects concerned the violations of permitted levels of certain factors (the level of bonded chlorine and water turbidity. It was found that the personal load of the pool results in an increase of the contamination introduced into the water. Also, the factors indicating an increase in anthropogenic pollution in pool water include concentration of bonded chlorine and potassium. The quality of swimming pool water was also influenced by the pool structure (in the case of free chlorine concentrations found lower), the time spent inside the pool by the users (lower turbidity in swimming pools), as well as its intended use (total organic carbon concentration varies depending on the facility and circulation). Supporting physicochemical evaluation with tools in the field of ecotoxicology is a new possibility in the analysis of pool water quality. However, it should be borne in mind that performing such analyzes requires proper sample preparation, in particular free chlorine removal. For this reason, it would be more appropriate to use biotests in assessing the effectiveness of treatment processes. In the standard toxicity analysis, a parallel assessment should be performed using different test organisms. It is important to choose appropriate organisms for the test group so as to limit e.g. the risk of obtaining results of mutually exclusive results. The quality and composition of rinse water depended, inter alia, on the type of filter bed. In the washing liquids formed after rinsing the pressure filters, a large amount of the total suspension corresponded to the flocculated from the flocculent bed after contact coagulation. In contrast, in the washing liquids from the cleaning of the washed bed, the suspended matter was made up of spent diatomaceous earth. The large amount of total suspension and the increased concentration of chlorine causes that the rinsing liquids of the filters cannot be directly discharged into the environment. Despite the lack of phytotoxicity in the performed biotests. The processes of sedimentation and physical dechlorination have contributed to a significant improvement in the quality of washings. The problem identified was the large differences in the quality of the washings obtained between consecutive filtration cycles, which significantly hinders prediction of the effectiveness of the cleaning results obtained. The coagulation process worked very well in purifying washings, including removing general slurry. However, it requires the addition of additional chemicals. And it can also cause an increase in the concentration of aluminum in the washing liquids coming from the pressure filters rinsing. Phytotoxicity of sediments after coagulation and supernatant liquids strongly depends on the value of physicochemical parameters of raw washings. Therefore, it is difficult to estimate the toxicological quality of the coagulation products obtained. Pressure diaphragm processes were characterized by high efficiency in removing impurities present in the washings. The ultrafiltration process achieved significant turbidity retention and UV ultraviolet absorbance254However, due to the knowledge about the type of organic contaminants introduced by bathers, it was reasonable to use the process of nanofiltration to purify the pool water. An obstacle in the use of membrane processes in the pool water treatment circuits is the reduction of transport capacity of membranes, as a result of blocking pores, as well as degradation of their surface as a result of contact with chlorine. For this reason, it is necessary to introduce processes that prepare the feed for membrane filtration. The aeration process did not contribute to the improvement of transport and separation capacities of ultra- and nanofiltration membranes. A significant improvement in the properties of the tested membranes was obtained in integrated coagulation - sedimentation - membrane filtration systems, with the final efficiency depending on the coagulant dose, the washing temperature and sedimentation time. The integrated process including two-stage ultrafiltration and nanofiltration allowed to obtain a high-quality permeate that could feed the pool circuit. The research confirmed that despite the growing requirements for the quality of swimming pool water, it is necessary to conduct further work on the possibilities of modernization of swimming pool water circulations.
... Therefore, the cleaning workers in the swimming pools and spas are exposed to numerous disinfection byproducts (DBPs) that are present in the indoor air of the pool areas. These include irritative compounds such as chloramines and trihalomethanes (THMs) and have been the subject of several previous studies (Caro and Gallego 2007;Zwiener et al. 2007;Lee et al. 2009Lee et al. , 2010Weaver et al. 2009;Richardson et al. 2010;Bessonneau et al. 2011;Schmalz et al. 2011a;Hansen et al. 2012;Westerlund et al. 2015). DBPs are formed in the reactions of the disinfecting chemicals (often NaClO) and organic or inorganic impurities, originating for example from toiletries, sweat, and urine (Hery et al. 1995;Judd and Black 2000;Hsu et al. 2009;Hansen et al. 2012). ...
Article
Full-text available
Swimming pools and spas require a high hygiene level, and therefore constant cleaning. In this study, cleaning workers’ exposure to volatile organic compounds (VOCs), trichloramine (TCA), and particulate matter (PM) in the swimming pools and spas were evaluated. Also, statistical methods were employed to determine what activities affect the exposure to disinfection byproducts (DBPs). The study was conducted in 32 swimming pools and spas. The measurement locations were pool areas, bathrooms, and locker rooms, both during cleaning and opening hours. During the cleaning, the total volatile organic compound (TVOC) concentrations were low, on average 96, 251, and 91 µg/m³ for locker rooms, bathrooms, and pool areas, respectively. Similarly, during the opening hours, the TVOC concentrations were on average 78, 125, and 83 µg/m³, for locker rooms, bathrooms, and pool areas, respectively. This is in line with previous studies investigating cleaning work in other environments. The most prevalent compounds during the cleaning were 2-(2-butoxyethoxy)ethanol (DEGBE), 2-(2-ethoxyethoxy)ethanol (DEGEE), 2-butyl-1-octanol, trichloromethane (chloroform), decamethylcyclopentasiloxane (D5), and carbon tetrachloride. The most prevalent compounds during the opening hours were D5, D-limonene, carbon tetrachloride (bathrooms and pool areas), and trichloromethane (bathrooms and pool areas). The TCA concentrations during the cleaning in the bathrooms and pool areas were on average 60 and 67 µg/m³, respectively, and during the opening hours, 28 and 122 µg/m³, respectively. The use of disinfectants was found to increase the TCA concentration in the bathrooms, while the other cleaning products did not. Even though the TCA concentrations were below the WHO’s guideline and the Finnish occupational exposure limit value of 500 µg/m³, the measured TCA levels were occasionally high enough to pose a risk of irritative symptoms. The PM concentrations were low, both in the real-time monitoring (aerodynamic diameter, Dae ≤ 15 µm) and inhalable dust samples (Dae ≤ 100 µm). Highest measured inhalable dust concentration was 350 µg/m³, well below the Finnish occupational limit value of 5,000 µg/m³ for organic inhalable dust.
... They are then inhaled, which is connected with risks of becoming ill with asthma, allergies, or other respiratory diseases for long-term swimming pool users. The solution to the problem may be, among others using proper water treatment [32][33][34][35] or proper ventilation [35][36][37] . ...
... It should be noted that this observation does not necessary indicate that the water quality is improved in periods of high attendance because other hazards are very likely to be augmented as consequence of occupancy and the bathers' inputs to water (namely microbiologic agents). In light of the results from various studies employing multipathway assessment models, revealing that inhalation route has the highest percentual contribution to the total cancer risk associated to THM exposure in swimming pools (Chen et al., 2011;Gouveia et al., 2019;Hang et al., 2016;Lee et al., 2009), our findings suggest that vulnerable people such as infants, children, elderly and people with chronic diseases should prefer the early morning period to perform their swimming practices. The results presented in Fig. 3A show that TTHM concentration measured in the air immediately above the water surface was significantly higher than in the air of the surrounding environment of the pool (first activity: z = −2.46, ...
Article
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Air exposures occurring in indoor swimming pools are an important public health issue due to their popularity and regular use by the general population, including vulnerable groups such as children and elderly people. More comprehensive information on indoor air quality (IAQ) in swimming pools is thus needed in order to understand health risks, establish appropriate protective limits and provide evidence-based opportunities for improvement of IAQ in these facilities. In this context, twenty public indoor swimming pools located in the Northern Region of Portugal were examined in two sampling campaigns: January-March and May-July 2018. For each campaign, a comprehensive set of environmental parameters was monitored during the entire period of the facilities' operating hours of a weekday, both indoors and outdoors. In addition, four air (1-h samplings) and water samples were collected. Findings show that comfort conditions, ultrafine particles number concentrations and exposure to substances in the indoor air (concentration and composition) is likely to vary greatly from one public indoor swimming pool to another. Trihalomethanes (THM) and dichloroacetonitrile were the predominant disinfection by-products identified in the indoor air but other potentially hazardous volatile organic compounds, such as limonene, 1,2,4-trimethylbenzene, 2,2,4,4,6,8,8-heptamethylnonane, 2- and 3-methylbutanenitrile, acetophenone, benzonitrile, and isobutyronitrile were found to have relevant putative emission sources in the environment of the swimming pools analyzed. Furthermore, indicators of poor ventilation conditions (namely carbon dioxide, relative humidity and existence of signs of condensation in windows) and some water-related parameters (THM levels, conductivity and salinity) were found to be determining factors of the measured airborne THM concentrations that appeared to significantly potentiate the exposure. In summary, this work provides evidence for the need to establish adequate standards for the comprehensive evaluation of IAQ in public swimming pools, in order to guide further development of evidence-based prevention/remediation strategies for promoting healthy environments in swimming pools.
... 22,23 It turns out that THMs are highly volatile, and some reports claim that THMs are absorbed via the respiratory route. [24][25][26] Erdinger et al 27 demonstrated that the content of THMs in swimmers' blood is correlated with their content in the ambient air of swimming pools and not with the content in the water, and with a direct impact of swimming intensity on THM accumulation in the organism of swimmers. ...
Preprint
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Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming-pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since they have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of these volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming-pools (water ingestion, skin absorption and inhalation) contribute to the individual exposome. CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated-pools as customers, particularly children, may also be affected has been a matter of debate. In this article, the EAACI Joint Task Force of the Working Group of Allergy, Asthma & Sports and the Interest Groupf of Environmental & Occupational Allergy discusses the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports and recreational attendance) and identify the main recommendations and unmet needs for research in this area.
... The presence of these species in raw water facilitates the reproduction of microorganisms in drinking water distribution systems. They also induce the utilization of a high chlorine dose and act as the precursor for the formation of harmful disinfection by-products (DBP), such as trihalomethanes (THMs), which are classified as potentially carcinogenic chlorine organic compounds (Lee et al., 2009). They can cause a reducing in the efficiency of water treatment facilities by interfering with various oxidants, increasing the solubility of heavy metals due to complexation with metals and adsorbed organic pollutants (Yang et al. 2007). ...
Article
Full-text available
Removal of natural organic matter from water using chemically activated coffee husk The presence of natural organic matter (NOM) in source water has posed many challenges for conventional water treatment facilities. Small organic acids, such as humic acid, present in NOM, have a high potential to influence the performance of water treatment processes. Uncontrolled application of agricultural chemicals leads to the simultaneous presence of toxic substances. In this work, batch adsorption experiments were conducted to examine the biosorp-tion of HA onto chemically activated coffee husk. The biosorption process was studied as a function of operating conditions, such as contact time, pH of the solution, HA concentration, adsorbent dose and agitation speed parameters. Experimental results showed that the adsorption has an equilibrium time of 60 min with a maximum adsorption of 93.7%. The optimum pH for maximum HA adsorption was found to be 5.5, with a maximum adsorption of 94.3%.. As the dose of adsorbent increased from 1 to 25 g/L, the concentration of HA was observed to reduce from 10 to 1.67 mg/L which is below the WHO (World Health Organization) guideline value of 2 mg/L. The amount of HA adsorbed increased with increasing the initial adsorbent concentration from 0.5 to 20 mg/L. The adsorption kinet-ics well fitted the pseudo-second order model with the correlation coefficient R2 = 0.997 and Ks = 0.078. The experimental sorption equilibrium can be represented by the Langmuir isotherm (R2 = 0.998, SSE = 0.006). An average desorption capacity of 87.3% was observed. The study shows that chemically activated coffee husk can be a potential candidate to be used as a biosorbent in the removal of NOM from aqueous solutions. ABSTRACT AJCR: https://escipub.com/american-journal-of-chemical-research/ 1
... urine, sweat, cosmetics, lotions, skin cells, hair, etc.) (Chowdhury et al., 2014;Kanan and Karanfil, 2011;Kim et al., 2002) ( Figure 2). Continuous contaminants and chlorine addition, together with water recirculation with a long replacement time can enhance DBP formation in the pool water (Glauner et al., 2005;Lee et al., 2009). ...
... Similarly, CR inge , CR derm , and CR inha are total carcinogenic risks for the total OPEs through oral ingestion, dermal contact, and inhalation absorption, respectively. The same SF are adopted for the SF inge,i , SF derm,i , and SF inha,I because of the shortage of available data as other studies (Lee et al., 2009;Li et al., 2018b;Wang et al., 2019). The values of RfD and SF for OPEs are listed in Table S3 of the Supplementary Information. ...
Article
Organophosphate esters (OPEs) are extensively used as flame retardants and plasticizers in China; however, their potential carcinogenicity causes great concern. To date, their environmental distribution in water samples from the lower Yangtze River Basin still remains uncharacterized. This study systematically investigated the occurrence and spatial distribution of 13 OPEs, as well as their associated potential risks, in water samples from the lower Yangtze River and its 88 major inflowing rivers. The total OPE (ΣOPE) concentrations ranged from 55.6 to 5071 ng/L, with a median of 144 ng/L. Among them, halogenated OPEs were the dominant group with an average of 61.6%, and tris(1-chloro-2-propyl) phosphate (12.6–450 ng/L, median: 53.38 ng/L) and tris(2-choroethyl) phosphate (11.0–1202 ng/L, median: 36.4 ng/L) were the most abundant OPEs. Significantly different concentrations were found with spatial variations (p < 0.01), and were higher in southern cities than in northern cities of the lower Yangtze River Basin. Principal component analysis with multiple linear regression and Spearman correlations showed that the main sources were likely emission of vehicular and marine traffic. Ecological risk analysis showed that the risk quotient (RQ) values of samples remained below 1, but the percentage of 0.1 < RQ ≤ 1 was 26.9%, indicating a medium risk of OPEs in water samples. Moreover, ethylhexyl diphenyl phosphate predominantly contributed to the ecological risk, accounting for >89.2% of the total ecological risk of ΣOPEs. However, the total non-carcinogenic and carcinogenic risks of ΣOPEs were negligible at the detected concentrations, even in a high exposure scenario. The risks from major inflowing rivers of the lower Yangtze River were almost one order of magnitude higher than those of the mainstream lower Yangtze River.
... Les THM ont été détectés et quantifés à des concentrations importantes dans les eaux et l'air des piscines ; ils représentent de 5 à 10% des composés organohalogénés totaux (méthode AOX). Les molécules majoritaires sont le chloroforme (CHCl3) ou le bromoforme (CHBr3) lorsque l'eau -désinfectée au chlore-est riche en bromures (comme l'eau de mer) ou lorque l'eau est désinfectée au brome (Aggazzotti et Predieri, 1986;Beech et al., 1980;Erdinger et al., 2004;Fantuzzi et al., 2001;Lee et al., 2009;Nieuwenhuijsen et al., 2000;Simard et al., 2013;Weaver et al., 2009 ;Lourencetti et al., 2012;Parinet et al., 2012;Manasfi et al., 2016). Les THM incluent également le dichlorobromométhane et le bromodichlorométhane. Le tableau 3-B de l'annexe 3 présente les concentrations médianes trouvées dans les eaux de piscine de différents pays. ...
... 22,23 It turns out that THMs are highly volatile, and some reports claim that THMs are absorbed via the respiratory route. [24][25][26] Erdinger et al 27 demonstrated that the content of THMs in swimmers' blood is correlated with their content in the ambient air of swimming pools and not with the content in the water, and with a direct impact of swimming intensity on THM accumulation in the organism of swimmers. ...
Article
Full-text available
Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming-pools. Among the disinfection options, the approaches using chlorine-based products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by-products (CBPs). The formation of CBPs is of particular concern since some have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming-pools (water ingestion, skin absorption and inhalation) contribute to the individual exposome. Some CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated-pools as customers, particularly children, may also be affected has been a matter of debate. In this article, we discuss the current evidence regarding the health effects of both acute and chronic exposures in different populations (work-related exposures, intensive sports and recreational attendance) and identify the main recommendations and unmet needs for research in this area. link: http://doi.org/10.1111/all.15014
... Chlorine-based disinfectants threaten human health, agricultural production, environmental quality and aquatic ecosystem health in a variety of ways by (1) reaction with Natural Organic Matter (NOM) or bromide in raw-water leads to the formation of DBPs such as Trihalomethanes (THMs), bromates, effl uent and other chemical compounds which poses acute toxicity to human health, aquatic ecosystem and other consumers [13][14][15][16][17]. (2) The direct toxic effect of chlorinebased chemicals on the aquatic organisms including vegetative bacteria, mycobacteria, viruses, and fungi by destroying their cell membranes, the cell hydrophobicity, as well as total Adenosine Triphosphate (ATP) [18,19]. ...
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Because of the current situation regarding the Covid-19 pandemic in more than 200 countries and territories, an early discussion is proposed on the use of chlorinebased disinfectants as an important precautionary measure to disinfect the surfaces and kill the Covid-19. However, the excessive use of chlorine-based disinfectants will surely make the highest residual concentrations in the water, soil, and other environmental components by various means such as surface runoff and leaching, etc. Crossing the permissible limits in water and soil system and in other environmental components will pose risks to human health in the form of skin, eyes, cancer, and other associated diseases. Similarly, it may also decline the agricultural production by excessive salt (Cl- ) accumulations (salinization) and will also threaten the aquatic and wild ecosystems. Therein, the ecological integrity assessments regarding the use of chlorine-based disinfectants in the current situation are very much important. Meanwhile, this will open a new area of interest for the researcher and would be of great importance to investigate its critical levels in the environmental components and its potentially toxic effects.
... 24 For adults in SPWs, IR, ET, EF, and ED were 25 mL h À1 , 1.3 h per event, 120 event per year, and 30 years, respectively. 25 For DWs, IR was 2.14 L per day for males and 2 L per day for females, 26 EF was 365 days per year, and ED was the same as ATL. The PC was 1-3 Â 10 À3 cm h À1 . ...
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... Zeng et al. (2020) proposed for the disinfection three methods, i.e., ultraviolet irradiation (UV) and two UV-based advanced oxidation processes (UV-AOPs) (UV/ hydrogen peroxide, UV/H 2 O 2 and UV/peroxymonosulfate, UV/ PMS). The use of chemicals for water disinfection, which simultaneously have strong oxidizing properties, causes the formation of disinfection by-products (DBPs) such as trihalomethanes (THM) (Lee et al., 2009), organic acids (Zhang et al., 2020), aldehydes and other unidentified compounds (Lee et al., 2010). Some substances occurring in water, such as i.e. bromides and natural organic matter (NOM), are the precursors of halogenated DBP in drinking water (Yin et al., 2020). ...
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... Human health risks due to DBPs exposure can be mitigated through the adoption of appropriate control strategies. Development of a specific DBPs control strategy is based on a number of ISP design and management factors including, pool types (e.g., leisure pools, lap pools, hot tubs) (Daiber et al., 2016;Hery et al., 1995), source water quality (e.g., organic and inorganic precursors, pH, temperature) (Hansen et al., 2012;Kanan and Karanfil, 2011;Kim et al., 2002;LaKind et al., 2010;Simard et al., 2013), disinfection processes (methods) (e.g., UV treatment, chlorination, ozonation) (Lee et al., 2009;McMaster, 2011;Richardson et al., 2010), bathers (e.g., number, behavior, and personal hygiene condition) (Chu and Nieuwenhuijsen, 2002;Daiber et al., 2016;Kristensen et al., 2010), and air ventilation conditions (Bessonneau et al., 2011;Jacobs et al., 2007). ...
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Disinfectants are added to swimming pools to kill harmful pathogens. Although liquid chlorine (sodium hypochlorite) is the most commonly used disinfectant, alternative disinfection techniques like electrochemically generated mixed oxidants or electrochemically generated chlorine, often referred to as salt water pools, are growing in popularity. However, these disinfectants react with natural organic matter and anthropogenic contaminants introduced to the pool water by swimmers to form disinfection byproducts (DBPs). DBPs have been linked to several adverse health effects, such as bladder cancer, adverse birth outcomes, and asthma. In this study, we quantified 60 DBPs using gas chromatography-mass spectrometry and assessed the calculated cytotoxicity and genotoxicity of an indoor community swimming pool before and after switching to a salt water pool with electrochemically generated chlorine. Interestingly, the total DBPs increased by 15% upon implementation of the salt water pool, but the calculated cytotoxicity and genotoxicity decreased by 45% and 15%, respectively. Predominant DBP classes formed were haloacetic acids, with trichloroacetic acid and dichloroacetic acid contributing 57% of the average total DBPs formed. Haloacetonitriles, haloacetic acids, and haloacetaldehydes were the primary drivers of calculated cytotoxicity, and haloacetic acids were the primary driver of calculated genotoxicity. Diiodoacetic acid, a highly toxic iodinated DBP, is reported for the first time in swimming pool water. Bromide impurities in sodium chloride used to electrochemically generate chlorine led to a 73% increase in brominated DBPs, primarily driven by bromochloroacetic acid. This study presents the most extensive DBP study to-date for salt water pools.
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W pierwszej części artykułu przedstawiono cechy fizykochemiczne zanieczyszczeń olejowych, główne źródła oraz omówiono procesy zachodzące po ich dostaniu się do wody. W drugiej części natomiast przybliżono pojęcie sorpcji i sorbentu, przy-wołano podstawowe ich podziały i wymieniono, jakie cechy powinien mieć sorbent dobrze adsorbujący zanieczyszczenia olejowe.
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In many countries water disinfection for human consumption is still carried out via chlorination which generates by-products such as trihalomethanes (THM). Exposure to THM constitutes a public health risk as such substances are known to be carcinogenic. This study evaluated exposure to THMs by inhalation in showers and assessed the carcinogenic risk for lifetime exposure. The study population involved students at Universidad de los Andes residing in Bogotá, Colombia. The risk assessment was performed stochastically and the exposure parameters were taken as probability distributions. Most variables were measured in relation to the chosen population. The risk was calculated using two different methodologies but no significant variations were obtained. The average risk calculated for men and women was 56 cases in a million (5.6 × 10⁻⁵). A sensitivity analysis was carried out where it was found that the parameters that increase risk the most are the concentration of chloroform in the water, exposure time, and the volume of the shower cubicle.
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Trihalomethanes (THMS) are chemicals that are formed when naturally occurring organic materials combine with free chlorine as disinfection byproducts. In spite of the fact that there is a peril of utilizing THMs in chlorinated drinking water, the health dangers of un-disinfected water is much greater. Therefore, this study concerned with lowering chlorine dose to amount adequate to kill waterborne pathogen with low concentration of THMs compound formation. The analysis program was conducted in Qena district at 5 fixed points comprised Salhyia plant outlet and four sites represented beginnings, middle and end of the plant network to determine the presence of chlorine disinfection by-products in treated water with respect to the disinfection process. So, chlorine dose, THMs compounds concentration, temperatures and bacteriological counts were measured a long three months. The results showed that when the chlorine dose reduced gradually to 4 mg L-1, formation of chloroform, bromoform, dichlorobromomethane and total THM compounds in the plant outlet decreased gradually and reached to its least concentration (6.2, 3.3,0.0, 10.9 μg L-1 respectively) and inhibited in some cases. This reduction in THM compound formation was also directly proportional to decreasing in temperature ratios. Moreover, bacteriological analysis showed that chlorine reduction did not affect its disinfection efficiency even at the end of the network. So it is recommended to reduce the population's exposure to halogenated organic compounds in drinking water by decreasing the chlorine dose without affecting the disinfection efficiency.
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Disinfection is an essential technological stage in water treatment. It is used not only for potable water but also for, e. g., swimming pool water. Water chlorination is the most common method for eliminating microorganisms today. However, active chlorine reacting with natural and anthropogenic compounds dissolved in water gives rise to the formation of numerous compounds that may be hazardous to human health. The assortment of anthropogenic contaminants grows every year; UV filters are well represented among them. Since recently, they are referred to as ecotoxicants, while their application to skin protection becomes more and more popular all over the world. Over 30 compounds, including numerous halogenated derivatives forming in the aquatic chlorination of a popular UV filter avobenzone in the presence of inorganic salts of iron and copper, as well as bromides and iodides, were identified by gas-chromatography–high-resolution mass spectrometry. The study demonstrated the notable variation of the qualitative and quantitative composition of the reaction products depending on the added salt. It is worth mentioning the formation of brominated and iodinated products.
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We measured the concentrations of Trihalomethanes (THMs), Chloroform (TCM), Bromodichloromethane (BDCM), Dibromochloromethane (DBCM) and Bromoform (TBM), in water, indoor air and exhaled air before and after using chlorine and ozone-chlorine disinfected swimming pools from September 2020 to January 2021. Two parallel panels of adult subjects swam for 60 min in a chlorine and an ozone-chlorine indoor swimming pool. The concentration of total THMs (tTHMs) in water samples of chlorine and ozone-chlorine swimming pools were in the ranges of 170.8–192.5 μg/L and 161.3–180.4 μg/L, respectively which exceeded the WHO guideline value. High levels of THMs were found in indoor air at the height of 10 cm compared to 150 cm above water surface. We found a statistically significant correlation between the concentration of THMs in water and indoor air samples. The results showed that the levels of all detected THMs in participant’ exhaled air after 60 min swimming were 11–13 times higher than those of before exposure. A statistically significant linear correlation was observed between THMs levels in the exhaled air and indoor air at the height of 10 cm above the water surface, but not with the levels at the height of 150 cm. We also found that the levels of THMs in exhaled air were associated with the energy expenditure, swimming distance and time, but not correlated with BMI and skin area.
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Colorimetric fiber optic sensor was developed for determination of total and residual chlorine in water. Developed sensor is based on absorption and detects values in the red, green, blue color space which is converted in user-oriented hue, saturation, value color model. Hue, saturation, value color model is enforced to simplify determination of the key chemical parameters concentration in water. Concentrations of total and residual chlorine in swimming pool water samples were measured by standard chemical laboratory analysis and compared with concentrations obtained by sensor, to approve the repeatability and effectiveness of the innovative method for measurements in water. In addition, results obtained by analysis of surface water and swimming pool water were compared in order to prove effectiveness of sensor for different water media. The absolute value between the two compared methods for the total chlorine concentrations was in the range from 0.014 to 0.067 mg/L and for residual chlorine from 0.002 to 0.06 mg/L. The linearity of calibration curve, limit of detection and quantitation, accuracy and precision are investigated to prove the validation of the analytical procedure to determine chlorine species by sensor. Used sensor method with its advantages (efficiency, low cost, simple use, small size, repeatability) was used on laboratory scale for the first time separately for total chlorine and residual chlorine and demonstrates possibility to replace expensive standard analytical laboratory equipment.
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This study aimed to estimate chronic daily intake (CDI) and to predict the attributable lifetime cancer risk (LCR) and hazard index (HI) from concurrent exposure to four trihalomethanes (THMs; chloroform, bromodichloromethane, dibromochloromethane and bromoform), via multiple exposure routes (oral ingestion, dermal contact and inhalation), among 238 non-competitive attendees of 10 Portuguese public indoor swimming pools (SPs), using a probabilistic approach based on Monte Carlo simulations. Exposure parameters of study participants were collected via questionnaires and THMs levels in SPs water were determined according the respective normative standards. The CDI for total THMs calculated for male and female participants considering all routes was 7.52 and 8.97 mg/kg/day, respectively. SP attendees presented higher CDI through inhalation than via the other two exposure routes, and chloroform was the compound contributing the most to total THMs CDI. The risk analysis indicated that the total LCR and HI from the targeted THMs were higher than the negligible risk levels (1 × 10⁻⁶ and 1, respectively) in the scenarios examined (central tendency exposure and reasonable maximum exposure), and the health risk for females was slightly higher than for males. This study suggests that there are possible adverse health risks, thus, to protect pool attendees, adequate mitigation measures, and comprehensive regulatory guidelines on individual THMs concentrations are needed.
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Quantification of regulated and emerging disinfection byproducts (DBPs) in swimming pool water, as well as the assessment of their lifetime health risk are limited in China. In this study, the occurrence of regulated DBPs (e.g., trihalomethanes, haloacetic acids) and emerging DBPs (e.g., haloacetonitriles, haloacetaldehydes) in indoor swimming pool water and the corresponding source water at a city in Eastern China were determined. The concentrations of DBPs in swimming pool water were 1-2 orders of magnitude higher than that in source water. Lifetime cancer and non-cancer risks of DBPs stemming from swimming pool water were also estimated. Inhalation and dermal exposure were the most significant exposure routes related to swimming pool DBP cancer and non-cancer risks. For the first time, buccal and aural exposure were considered, and were proven to be important routes of DBP exposure (accounting for 17.9%-38.9% of total risk). The cancer risks of DBPs for all swimmers were higher than 10⁻⁶ of lifetime exposure risk recommended by United States Environmental Protection Agency, and the competitive adult swimmers experienced the highest cancer risk (7.82 × 10⁻⁵). These findings provide important information and perspectives for future efforts to lower the health risks associated with exposure to DBPs in swimming pool water.
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This study aimed to understand the exposure levels of trihalomethanes (THMs) in an indoor swimming pool and calculate the risks of exposure to THMs, based on the presence of each THM species, of children swimmers aged 6–17, in Beijing, China. We obtained exposure factors for the children through questionnaires and measured THM concentrations through laboratory tests, and we combined the results with an exposure model to calculate the risks, with consideration of different exposure routes (oral ingestion, inhalation and dermal absorption). In terms of exposure factors for the swimmers aged 6–17, the average body weight, exposure duration, exposure frequency, swimming time, shower time, changing time, warm-up exercise and rest time, skin surface area and ingestion rate of pool water were 40.46 kg, 2.70 years, 96 events/year, 64.03 min/event, 17.04 min/event, 15.31 min/event, 12.71 min/event, 1.37 m2 and 48.93 ml/event, respectively. The THM concentrations in swimming pool water, shower water, swimming pool air and locker room air were 67.17 μg/L, 12.64 μg/L, 358.66 μg/m3 and 40.98 μg/m3, respectively. The average cancer risk of THMs was 5.44 × 10−6, which is an unacceptable risk according to the United State Environmental Protection Agency(USEPA) Guidelines. The average hazard index was 0.007, i.e., less than 1, indicating that the noncancer risk was acceptable. TCM was the main substance in 4 species of THMs. and inhalation exposure was the main exposure pathway. The risk of cancer and noncancer from inhalation exposure to THMs accounts for 97%-99% of the total risk. As a result, the disease control authorities and administrative department should pay attention to the health and safety of swimming facilities and, at the same time, establish standards for THMs in the air through further research.
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Swimming pools adopt chlorination to ensure microbial safety. Giardia has attracted attention in swimming pool water because of its occurrence, pathogenicity, and chlorine resistance. To control Giardia concentrations in pool water and reduce the microbial risk, higher chlorine doses are required during disinfection. Unfortunately, this process produces carcinogenic disinfection byproducts that increase the risk of chemical exposure. Therefore, quantitatively evaluating the comparative microbial vs. chemical exposure risks that stem from chlorination inactivation of Giardia in swimming pool water is an issue that demands attention. We simulated an indoor swimming pool disinfection scenario that followed common real-world disinfection practices. A quantitative microbial risk assessment coupled with a chemical exposure risk assessment was employed to compare the Giardia microbial exposure risk (MER) and the trihalomethane chemical exposure risk (CER) to humans. The results demonstrated a 22% decrease in MER- and CER-induced health exposure risk, from 8.45E-5 at 8:00 to 6.60E-5 at 19:00. Both the MER and CER decreased gradually, dropping to 3.26E-5 and 3.35E-5 at 19:00, respectively. However, the CER exceeded the MER after 18:30 and became the dominant factor affecting the total exposure risk. Past the 18 h mark, the contribution of trihalomethane CER far exceeded the risk aversion from microbial inactivation, leading to a net increase in total exposure risk despite the declining MER. Swimmers may consider swimming after 19:00, when the total exposure risk is the lowest. Lowering water temperature and/or pH were identified as the most sensitive factors to minimize the overall health exposure risk.
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Taking samples at eight points chosen from two conventional water treatment plants for the city of Salamanca, the formation and evolution of THM levels were studied on 11 different dates. The values obtained were correlated statistically with the following parameters: concentration of humic acids (only raw water), pre- and postchlorination dosages, UV absorbance (UV-254), pH and temperature. No statistical correlation was observed either with the humic acids content or with the organic matter measured as UV-254. A correlation was only found with the prechlorination dosage in the clarifiers of the old plant. However, in both plants there was a correlation with the postchlorination dosage although this was not very patent owing to the impossibility of knowing the contribution of each parameter at one of the sampling sites where postchlorination and pH correction are performed simultaneously. A clear linear correlation (r = 0.4345, P = 0.0001) was observed with temperature. Using stepwise regression (ANCOVA) a mathematical function was obtained (R = 0.8066, P = 0.0001) that relates the concentration of chloroform with temperature and the sampling points. From this it is deduced that both pH and temperature increase this concentration, although for each pH value all the In CHCl3 (μg/l) vs temperature curves showed a maximum (Tc = 18.97°C), after which chloroform levels decrease sharply. On attempting to quantify the contribution of the rest of the parameters studied here concerning the levels of THMs, it may be inferred that others should be considered, such as the design, the dimensions and the exploitation of the water treatment plants studied.
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Ozone has been proposed for water disinfection because it is more efficient than chlorine for killing microbes and results in much lower levels of carcinogenic trihalomethanes than does chlorination. Ozone leads to formation of hypobromous acid in surface waters with high bromine content and forms brominated organic by-products and bromate. The carcinogenicity and chronic toxicity of potassium bromate (KBrO3) was studied in male B6C3F1 mice and F344/N rats to confirm and extend the results of previous work. Mice were treated with 0, 0.08, 0.4, or 0.8 g/L KBrO3 in the drinking water for up to 100 wk, and rats were provided with 0, 0.02, 0.1, 0.2, or 0.4 g/L KBrO3. Animals were euthanatized, necropsied, and subjected to a complete macroscopic examination. Selected tissues and gross lesions were processed by routine methods for light microscopic examination. The present study showed that KBrO3 is carcinogenic in the rat kidney, thyroid, and mesothelium and is a renal carcinogen in the male mouse, KBrO3 was carcinogenic in rodents at water concentrations as low as 0.02 g/L (20 ppm; 1.5 mg/kg/day). These data can be used to estimate the human health risk that would be associated with changing from chlorination to ozonation for disinfection of drinking water.
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Exposure to drinking water disinfection by-products (DBPs), such as trihalomethanes (THMs), has been associated with bladder and colorectal cancer in humans. Exposure to DBPs has typically been determined by examining historical water treatment records and reconstructing study participants' water consumption histories. However, other exposure routes, such as dermal absorption and inhalation, may be important components of an individual's total exposure to drinking water DBPs. In this study, we examined individuals' exposure to THMs through drinking, showering, or bathing in tap water. Thirty-one adult volunteers showered with tap water for 10 min (n = 11), bathed for 10 min in a bathtub filled with tap water (n = 10), or drank 1 l of tap water during a 10 min time period (n = 10). Participants provided three 10 ml blood samples: one sample immediately before the exposure; one sample 10 min after the exposure ended; and one sample 30 min (for shower and tub exposure) or 1 h ( for ingestion) after the exposure ended. A sample of the water (from the tap, from the bath, or from the shower) was collected for each participant. We analyzed water samples and whole blood for THMs (bromoform, bromodichloromethane, dibromochloromethane, and chloroform) using a purge-and-trap/gas chromatography/mass spectrometry method with detection limits in the parts-per-quadrillion range. The highest levels of THMs were found in the blood samples from people who took 10 min showers, whereas the lowest levels were found in the blood samples from people who drank 1 l of water in 10 min. The results from this study indicate that household activities such as bathing and showering are important routes for human exposure to THMs.
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Samples of drinking water are routinely analysed for four trihalomethanes (THMs), which are indicators of by-products of disinfection with chlorine, by UK water suppliers to demonstrate compliance with regulations. The THM data for 1992-1993 to 1997-1998 for three water suppliers in the north and midlands of England were made available for a UK epidemiological study of the association between disinfection by-products and adverse birth outcomes. This paper describes the THM levels in these three supply regions and discusses possible sources of variation. THM levels varied between different suppliers' water, and average THM levels were within the regulatory limits. Chloroform was the predominant THM in all water types apart from the ground water of one supplier. The supplier that distributed more ground and lowland surface water had higher dibromochloromethane (DBCM) and bromoform levels and lower chloroform levels than the other two suppliers. In the water of two suppliers, seasonal fluctuations in bromodichloromethane (BDCM) and DBCM levels were found with levels peaking in the summer and autumn. In the other water supplier, chloroform levels followed a similar seasonal trend whereas BDCM and DBCM levels did not. For all three water suppliers, chloroform levels declined throughout 1995 when there was a drought period. There was a moderate positive correlation between the THMs most similar in their structure (chloroform and BDCM, BDCM and DBCM, and DBCM and bromoform) and a slight negative correlation between chloroform and bromoform levels.
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The occurrence and the fate of trihalomethanes (THMs) in the water supply system of Hanoi City, Vietnam was investigated from 1998 to 2001. The chlorination efficiency, THM speciation, and, THM formation potential (THMFP) was determined in the water works and in tap water. With regard to THM formation, three types of groundwater resources were identified: (I) high bromide, (II) low bromide, and (III) high bromide combined with high ammonia and high dissolved organic carbon (DOC) concentrations. Under typical treatment conditions (total chlorine residual 0.5-0.8 mg/L), the total THM formation was always below WHO, EU, and USEPA drinking water standards and decreased in the order type I > type II > type III, although the THMFP was > 400 micrograms/L for type III water. The speciation showed > 80% of bromo-THMs in type I water due to the noticeable high bromide level (< or = 140 micrograms/L). In type II water, the bromo-THMs still accounted for some 40% although the bromide concentration is significantly lower (< or = 30 micrograms/L). In contrast, only traces of bromo-THMs were formed (approximately 5%) in type III water, despite bromide levels were high (< or = 240 micrograms/L). This observation could be explained by competition kinetics of chlorine reacting with ammonia and bromide. Based on chlorine exposure (CT) estimations, it was concluded that the current chlorination practice for type I and II waters is sufficient for > or = 2-log inactivation of Giardia lamblia cysts. However, in type III water the applied chlorine is masked as chloramine with a much lower disinfection efficiency. In addition to high levels of ammonia, type III groundwater is also contaminated by arsenic that is not satisfactory removed during treatment. N-nitrosodimethylamine, a potential carcinogen suspected to be formed during chloramination processes, was below the detection limit of 0.02 microgram/L in type III water.
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Dermal contact with some organic disinfection by-products (DBPs) such as trihalomethanes in chlorinated drinking water has been established to be an important exposure route. We evaluated dermal absorption of two haloketones (1,1-dichloropropanone and 1,1,1-trichloropropanone) and chloroform while bathing, by collecting and analyzing time profiles of expired breath samples of six human subjects during and following a 30-min bath. The DBP concentrations in breath increased towards a maximum concentration during bathing. The maximum haloketone breath concentration during dermal exposure ranged from 0.1 to 0.9 microg / m(3), which was approximately two orders of magnitude lower than the maximum chloroform breath concentration during exposure. Based on a one-compartment model, the in vivo permeability of chloroform, 1,1-dichloropropanone, and 1,1,1-trichloropropanone were approximated to be 0.015, 7.5 x 10(- 4), and 4.5 x 10(- 4) cm / h, respectively. Thus, haloketones are much less permeable across human skin under normal bathing conditions than is chloroform. These findings will be useful for future assessment of total human exposure and consequent health risk of these DBPs.
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Cryptosporidium parvum oocysts and Clostridium perfringens spores are very resistant to chlorine and other drinking-water disinfectants. Clostridium perfringens spores have been suggested as a surrogate indicator of disinfectant activity against Cryptosporidium parvum and other hardy pathogens in water. In this study, an alternative disinfection system consisting of an electrochemically produced mixed-oxidant solution (MIOX; LATA Inc.) was evaluated for inactivation of both Cryptosporidium parvum oocysts and Clostridium perfringens spores. The disinfection efficacy of the mixed-oxidant solution was compared to that of free chlorine on the basis of equal weight per volume concentrations of total oxidants. Batch inactivation experiments were done on purified oocysts and spores in buffered, oxidant demand-free water at pH 7 and 25°C by using a disinfectant dose of 5 mg/liter and contact times of up to 24 h. The mixed-oxidant solution was considerably mute effective than free chlorine in inactivating both microorganisms. A 5-mg/liter dose of mixed oxidants produced a >3-log10- unit (>99.9%) inactivation of Cryptosporidium parvum oocysts and Clostridium perfringens spores in 4 h. Free chlorine produced no measurable inactivation of Cryptosporidium parvum oocysts by 4 or 24 h, although Clostridium perfringens spores were inactivated by 1.4 log10 units after 4 h. The on- site generation of mixed oxidants may be a practical and cost-effective system of drinking water disinfection protecting against even the most resistant pathogens, including Cryptosporidium oocysts.
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Bladder cancer has been associated with exposure to chlorination by-products in drinking water, and experimental evidence suggests that exposure also occurs through inhalation and dermal absorption. The authors examined whether bladder cancer risk was associated with exposure to trihalomethanes (THMs) through ingestion of water and through inhalation and dermal absorption during showering, bathing, and swimming in pools. Lifetime personal information on water consumption and water-related habits was collected for 1,219 cases and 1,271 controls in a 1998-2001 case-control study in Spain and was linked with THM levels in geographic study areas. Long-term THM exposure was associated with a twofold bladder cancer risk, with an odds ratio of 2.10 (95% confidence interval: 1.09, 4.02) for average household THM levels of >49 versus < or =8 micro g/liter. Compared with subjects not drinking chlorinated water, subjects with THM exposure of >35 micro g/day through ingestion had an odds ratio of 1.35 (95% confidence interval: 0.92, 1.99). The odds ratio for duration of shower or bath weighted by residential THM level was 1.83 (95% confidence interval: 1.17, 2.87) for the highest compared with the lowest quartile. Swimming in pools was associated with an odds ratio of 1.57 (95% confidence interval: 1.18, 2.09). Bladder cancer risk was associated with long-term exposure to THMs in chlorinated water at levels regularly occurring in industrialized countries.
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Cryptosporidium parvum oocysts and Clostridium perfringens spores are very resistant to chlorine and other drinking-water disinfectants. Clostridium perfringens spores have been suggested as a surrogate indicator of disinfectant activity against Cryptosporidium parvum and other hardy pathogens in water. In this study, an alternative disinfectant system consisting of an electrochemically produced mixed-oxidant solution (MIOX; LATA Inc.) was evaluated for inactivation of both Cryptosporidium parvum oocysts and Clostridium perfringens spores. The disinfection efficacy of the mixed-oxidant solution was compared to that of free chlorine on the basis of equal weight per volume concentrations of total oxidants. Batch inactivation experiments were done on purified oocysts and spores in buffered, oxidant demand-free water at pH 7 an 25 degrees C by using a disinfectant dose of 5 mg/liter and contact times of up to 24 h. The mixed-oxidant solution was considerably more effective than free chlorine in activating both microorganisms. A 5-mg/liter dose of mixed oxidants produced a > 3-log10-unit (> 99.9%) inactivation of Cryptosporidium parvum oocysts and Clostridium perfringens spores in 4 h. Free chlorine produce no measurable inactivation of Cryptosporidium parvum oocysts by 4 or 24 h, although Clostridium perfringens spores were inactivated by 1.4 log10 units after 4 h. The on-site generation of mixed oxidants may be a practical and cost-effective system of drinking water disinfection protecting against even the most resistant pathogens, including Cryptosporidium oocysts.
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Chloroform, generally regarded as a non-genotoxic compound, is associated with the induction of liver and/or kidney tumors in laboratory mice and rats. In particular, chloroform produced renal tubule tumors in low incidence in male Osborne-Mendel rats when administered by corn-oil gavage or in the drinking water. There is a lack of data on intermediate endpoints that may be linked to renal cancer development in this strain of rat, in contrast to mice. Specifically, evidence linking chloroform-induced liver and kidney tumors in mice with cytotoxicity and regenerative cell proliferation is very strong, but weak in the rat. In the present study, kidney tissue from a carcinogenicity bioassay of chloroform in Osborne-Mendel rats was re-evaluated for histological evidence of compound-induced cytotoxicity and cell turnover. All rats treated with 1800 ppm (160 mg/kg/day, high-dose group) in the drinking water for 2 years and half the rats treated with 900 ppm (81 mg/kg/day) had mild to moderate changes in proximal convoluted tubules in the mid to deep cortex indicative of chronic cytotoxicity. Tubule alterations specifically associated with chronic chloroform exposure included cytoplasmic basophilia, cytoplasmic vacuolation, and nuclear crowding consistent with simple tubule hyperplasia. Occasional pyknotic cells, mitotic figures in proximal tubules, and prominent karyomegaly of the renal tubule epithelium were present. These alterations were not present in control groups or at the 200-ppm (19 mg/kg/day) or 400-ppm (38 mg/kg/day) dose levels. This new information adds substantially to the weight of evidence that the key events in chloroform-induced carcinogenicity in rat kidney include sustained cellular toxicity and chronic regenerative hyperplasia.
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The formation of trihalomethanes (THMs) in a model swimming pool using hypobromous and hypochlorous acids as disinfectants has been studied. Factorial design was used to generate and process data from systematically-conducted experiments on a series of 11 samples of swimming pool simulant. The variables considered were organic loading (urine and humic acid concentration), disinfectant type and concentration, incubation time and degree of agitation. A disinfectant concentration of 6 mg l−1 was used throughout. The variables affecting bromoform formation were urine and humic acid concentration and disinfectant type. Interactions were observed between humic acid and urine and also between urine and disinfectant. The effect of urine was to suppress bromoform formation. Levels of chlorine-containing THMs were unaffected by humic acid at the concentrations used; only the urine concentration and disinfectant type had a significant effect on these THMs. No interactions between any three or more variables were observed for any THM.
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Using a combination of spectral identification techniquesgas chromatography coupled with low- and high-resolution electron-impact mass spectrometry (GC/EI-MS), low- and high-resolution chemical ionization mass spectrometry (GC/CI-MS), and infrared spectroscopy (GC/IR)we identified many drinking water disinfection byproducts (DBPs) formed by ozone and combinations of ozone with chlorine and chloramine. Many of these DBPs have not been previously reported. In addition to conventional XAD resin extraction, both pentafluorobenzylhydroxylamine (PFBHA) and methylation derivatizations were used to aid in identifying some of the more polar DBPs. Many of the byproducts identified were not present in spectral library databases. The vast majority of the ozone DBPs identified contained oxygen in their structures, with no halogenated DBPs observed except when chlorine or chloramine was applied as a secondary disinfectant. In comparing byproducts formed by secondary treatment of chlorine or chloramine, chloramine appeared to form the same types of halogenated DBPs as chlorine, but they were generally fewer in number and lower in concentration. Most of the halogenated DBPs that were formed by ozone−chlorine and ozone−chloramine treatments were also observed in samples treated with chlorine or chloramine only. A few DBPs, however, were formed at higher levels in the ozone−chlorine and ozone−chloramine samples, indicating that the combination of ozone and chlorine or chloramine is important in their formation. These DBPs included dichloroacetaldehyde and 1,1-dichloropropanone.
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In general, chlorination is the method of drinking water disinfection most favoured by the water industry. Occasional outbreaks of water transmitted disease, the identification of chlorine as a source of potentially harmful disinfection by-products, and the emergence of recalcitrant pathogens has led to heightened regulation for the removal of microbial pathogens and disinfection by-products from drinking water. As a result, research and development of alternative disinfection technologies has intensified. Electrochemical disinfection has emerged as one of the more feasible alternatives to chlorination. Research using a range of cell configurations has shown electrochemical disinfection to be effective against a range of pathogens. However, in many of the systems, disinfection efficacy appears to be related to the generation of chlorine species. The apparent prevalence of chlorine as the mechanism of disinfection begs the question as to whether electrochemical disinfection has an advantage over chlorination in terms of its inactivation efficacy and potential to form disinfection by-products. This paper reports on a series of experiments evaluating the disinfection efficacy of an electrochemical disinfection technology against Escherichia coli and bacteriophage MS2. The results of these experiments conclude that electrochemical disinfection can be effective without the generation of chlorine species.
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Natural water, highly contaminated with coliforms, was electrochemically treated in a stirred batch system with the use of two Ti electrodes and direct current, the polarity of which alternated automatically in half cycles of 1 min. The process was found to be effective and the percentage of the initial concentration of bacteria which were destroyed was found to be proportional to both treatment time and the square of current density obeying the kinetic model α = ki2 t; consequently the time needed for complete disinfection was inversely proportional to the square of current density. The percentage above was found to be independent of the initial concentration of germs at least for the range of concentrations employed. The residual disinfection capacity, after completion of the electrochemical treatment, was also verified by mixing electrochemically treated, disinfected natural water with contaminated water.
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Water from swimming pools in the Miami area was analyzed for nitrates, chlorates and trihalomethanes. The average concentrations of nitrate and chlorate found in freshwater pools were 8.6 mg/liter and 16 mg/liter respectively, with the highest concentrations being 54.9 mg/liter and 124 mg/liter, respectively. The average concentration of total trihalomethanes found in freshwater pools was 125 micrograms/liter (mainly chloroform) and in saline pools was 657 micrograms/liter (mainly bromoform); the highest concentration was 430 micrograms/liter (freshwater) and 1287 micrograms/liter (saltwater). The possible public health significance of these results is briefly discussed.
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The presence of chloroform as the result of disinfection with sodium hypochlorite was demonstrated in the water and ambient air of indoor swimming pools. Environmental monitoring was performed in 12 indoor swimming pools in northern Italy and the level of human exposure was assessed. Biological monitoring performed by gas chromatography on human plasma and alveolar air samples evidenced that the uptake of chloroform in swimmers varies according to the intensity of the physical activity and age. The elimination of chloroform in alveolar air in one subject showed a very short half-life (from 20 to 27 min) and a complete clearance within 10 h after the end of exposure.
Article
In this article, exposure to trihalomethanes (THMs) in indoor swimming pools as a consequence of water chlorination is reported. Environmental and biological monitoring of THMs was performed in order to assess the uptake of these substances after a defined period in five competitive swimmers, regularly attending an indoor swimming pool to train for competition during four sampling sessions. Analyses were performed by gas-chromatography and the following THMs were detected: chloroform (CHC13), bromodichloromethane (CHBrC12), dibromochloromethane (CHBrsC1) and bromoform (CHBr3). CHC13 appeared the most represented compound both in water and in environmental air before and after swimming. CHBrC1w and CHBr2C1 were always present, even though at lower levels than CHC13, CHBr3, was rarely present. In relation to biological monitoring, CHC13, CHBrC12 and CHBr2C1 were detected in all alveolar air samples collected inside the swimming pool. Before swimming, after 1 h at rest at the pool edge, the mean values were 29.4 +/- 13.3, 2.7 +/- 1.2 and 0.8 +/- 0.8 micrograms/m3, respectively, while after spending 1 h swimming, higher levels were detected (75.6 +/- 18.6, 6.5 +/- 1.3 and 1.4 +/- 0.9 micrograms/m3, respectively). Only CHC13 was detected in all plasma samples (mean: 1.4 +/- 0.5 micrograms/1) while CHBrC1x and CHBr2C1 were observed only in few samples at a detection limit of 0.1 micrograms/1. After 1 h at rest, at an average environmental exposure of approx. 100 micrograms/m3, the THM uptake was approx. 30 micrograms/h (26 micrograms/h for CHC1c, 3 micrograms/h for CHBrC12 and 1.5 micrograms/h for CHBr2C1). After 1 h swimming, the THM uptake is approx. seven times higher than at rest: a THM mean uptake of 221 micrograms/h (177 micrograms/h, 26 micrograms/h and 18 micrograms/h for CHC13, CHBrC12 and CHBr2C1, respectively) was evaluated at an environmental concentration of approx. 200 micrograms/m3.
Article
Chloroform, generally regarded as a non-genotoxic compound, is associated with the induction of liver and/or kidney tumors in laboratory mice and rats. In particular, chloroform produced renal tubule tumors in low incidence in male Osborne-Mendel rats when administered by corn-oil gavage or in the drinking water. There is a lack of data on intermediate endpoints that may be linked to renal cancer development in this strain of rat, in contrast to mice. Specifically, evidence linking chloroform-induced liver and kidney tumors in mice with cytotoxicity and regenerative cell proliferation is very strong, but weak in the rat. In the present study, kidney tissue from a carcinogenicity bioassay of chloroform in Osborne-Mendel rats was re-evaluated for histological evidence of compound-induced cytotoxicity and cell turnover. All rats treated with 1800 ppm (160 mg/kg/day, high-dose group) in the drinking water for 2 years and half the rats treated with 900 ppm (81 mg/kg/day) had mild to moderate changes in proximal convoluted tubules in the mid to deep cortex indicative of chronic cytotoxicity. Tubule alterations specifically associated with chronic chloroform exposure included cytoplasmic basophilia, cytoplasmic vacuolation, and nuclear crowding consistent with simple tubule hyperplasia. Occasional pyknotic cells, mitotic figures in proximal tubules, and prominent karyomegaly of the renal tubule epithelium were present. These alterations were not present in control groups or at the 200-ppm (19 mg/kg/day) or 400-ppm (38 mg/kg/day) dose levels. This new information adds substantially to the weight of evidence that the key events in chloroform-induced carcinogenicity in rat kidney include sustained cellular toxicity and chronic regenerative hyperplasia.
Article
Pre-oxidation is often applied to reduce the formation of disinfection by-products (DBPs). The aim of pre-oxidation is to remove the centers of natural organic matter (NOM) which are responsible for the formation of DBPs. In this paper, the differences between ozone- and OH-radical-induced oxidation to remove DBP-precursors are compared. The experiments were done with water of the River Ruhr (Germany) with a concentration of dissolved organic carbon (DOC) of 2 mg/l. Ozonation was able to remove DBP precursors selectively. After application of an absorbed ozone mass of 1.5 mg/mg DOC, a reduction in the formation potential for (THM-FP) and in the formation potential for organic halogen adsorbable on activated carbon (AOX-FP) down to 68 and 73% of the initial concentration was achieved, respectively. A removal of NOM was not achieved using absorbed ozone masses between 0.5 and 1.5 mg/mg DOC. In the hydrogen peroxide/UV process, in which OH-radicals are the reactive species, an increase in the THM concentration was measured after application of this process with short irradiation times. The maximum value of the THM-FP was 20% higher than the initial THM-FP. After an irradiation time of 1,050 min and a hydrogen peroxide consumption of 5.6 mg/l, the THM-FP and AOX-FP decreased to 75 and 71% of the initial formation potential, respectively. There was no selective removal of DBP precursors because the DOC concentration decreased also to 75% of the initial DOC-concentration after 1,050 min of irradiation.
Article
This population-based case-control study was conducted in southern Ontario, Canada from 1992 to 1994 to assess the relationship between chlorination by-products in public water supplies and cancers of the colon and rectum. Interviews providing residence and water source histories were completed by 76% of eligible cancer cases and 72% of eligible controls. Supplemental data from municipal water supplies were used to estimate individual exposure to water source, chlorination status, and by-product levels as represented by trihalomethanes (THMs) during the 40-year period before the interview. The analyses included 767 colon cases, 661 rectal cases, and 1545 controls with exposure information for at least 30 of these years (75% of subjects with completed interviews). Among males, colon cancer risk was associated with cumulative exposure to THMs, duration of exposure to chlorinated surface water, and duration of exposure to a THM level > or = 50 microg/liter and 75 microg/liter. Males exposed to chlorinated surface water for 35-40 years had an increased risk of colon cancer compared with those exposed for < 10 years (odds ratio, 1.53; 95% confidence interval, 1.13-2.09). Males exposed to an estimated THM level of 75 microg/liter for > or = 35 years had double the risk of those exposed for < 10 years (odds ratio, 2.10; 95% confidence interval, 1.21-3.66). In contrast, these relationships were not observed among females. No relationship was observed between rectal cancer risk and any of the measures of exposure to chlorination by-products. The results of this study should be interpreted with caution because they are only partially congruent with the limited amount of literature addressing this issue.
We have reviewed the relevant issues in the exposure assessment of disinfection by-products (DBPs) of chlorination for epidemiological and health risk assessment. Various DBPs can be detected in drinking water and swimming pools, and the reported levels show a considerable range, but were generally below the current health standard for total trihalomethanes (TTHMs) (100 microg/l). Relatively little information is available on the correlation between the various DBPs in drinking water and in swimming pools. Chloroform was generally, but not always, the most predominant DBP. In epidemiological studies, TTHM levels have been used as an indicator for total DBP load, even though TTHM levels do not always correlate well with individual DPBs. Factors such as residence time, temperature, pH, organic content, including humic and fulvic acid and bromide levels affect the composition and levels of DBPs. Although there are biomarkers of DBPs, mainly for chloroform and more recently for the other volatile trihalomethanes (THMs) and the nonvolatile haloacetic acids (HAAs) such as trichloroacetic acid (TCAA) and dichloroacetic acid (DCAA), they have not been used in epidemiological studies. The THMs have been measured in exhaled breath and serum, while the HAAs have been measured in urine. These biomarkers have been useful to estimate the actual uptake of the DBPs and the relative contribution of various exposure routes. Physiologically based pharmacokinetic (PBPK) models exist for, e.g. chloroform, but their main target organs are the kidney and liver and they have not been used in epidemiological studies. Tap water ingestion, showering, bathing, swimming, boiling water and dishwashing are all activities that have been associated with the uptake of DBPs, and considerable variation in these activities has been observed between people. No studies have reported on the correlation between human uptake of DBPs and water-zone mean estimates, but various studies found a good correlation between THM concentrations in exhaled breath and THM concentrations in water during showering and swimming. In general exposure assessment in epidemiological studies has been limited which complicates the interpretation. These findings have implications for epidemiological studies, particularly with reference to Berkson and classical error type models, study power, attenuation and precision of health-risk estimates and study efficiency. Recommendations are made for further areas of study.
Article
Data on concentrations of trihalomethanes (THMs) in raw and chlorinated water collected from three water treatment plants in Taiwan and estimates of the lifetime cancer risk for THMs from drinking water, using age-adjusted factors and volatilization terms, are presented. Data on THM levels in drinking water were obtained from the annual reports of the Environmental Protection Administration (EPA) of Taiwan. The methodology for estimation of lifetime cancer risks was taken from the USEPA. Chloroform was the major species of THMs, especially in the water plant of south Taiwan. Chloroform contributed the majority of the lifetime cancer risks (range: 87.5-92.5%) of total risks from the three water supply areas. All lifetime cancer risks for CHCl(3), CHBrCl(2), CHBr2Cl, and CHBr3 from consuming tap water in the three water supply areas were higher than 10(-6). The sum of lifetime cancer risks for CHCl(3), CHBrCl(3), CHBr2Cl, and CHBr3 was highest (total risk for total THMs<1.94x10(-4)) for tap water from south Taiwan.
Article
The study evaluated occupational exposure to trihalomethanes (THMs) in indoor swimming pools. Thirty-two subjects, representing the whole workforce employed in the five public indoor swimming pools in the city of Modena (Northern Italy) were enrolled. Both environmental and biological monitoring of THMs exposure were performed. Environmental concentrations of THMs in different areas inside the swimming pools (at the poolside, in the reception area and in the engine-room) were measured as external exposure index, while individual exposure of swimming pool employees was estimated by THMs concentration in alveolar air. The levels of THMs observed in swimming pool water ranged from 17.8 to 70.8 microg/l; the mean levels of THMs in ambient air were 25.6+/-24.5 microg/m3 in the engine room, 26.1+/-24.3 microg/m3 in the reception area and 58.0+/-22.1 microg/m3 at the poolside. Among THMs, only chloroform and bromodichloromethane were always measured in ambient air, while dibromochloromethane was detected in ambient air rarely and bromoform only once. Biological monitoring results showed a THMs mean value of 20.9+/-15.6 microg/m3. Statistically significant differences were observed according to the main job activity: in pool attendants, THMs alveolar air were approximately double those observed in employees working in other areas of the swimming pools (25.1+/-16.5 microg/m3 vs. 14.8+/-12.3 microg/m3, P < 0.01). THMs in alveolar air samples were significantly correlated with THMs concentrations in ambient air (r = 0.57; P < 0.001). Indoor swimming pool employees are exposed to THMs at ambient air levels higher than the general population. The different environmental exposure inside the swimming pool can induce a different internal dose in exposed workers. The correlation found between ambient and alveolar air samples confirms that breath analysis is a good biological index of occupational exposure to these substances at low environmental levels.
Article
The effect of ultraviolet radiation from low- and medium-pressure mercury arc lamps on Cryptosporidium parvum oocysts was studied using a collimated beam apparatus. Experiments were conducted using parasites suspended in both filtered surface water and phosphate buffered laboratory water. Inactivation of oocysts was measured as reduction in infectivity using a CD-1 neonatal mouse model and was found to be a non-linear function of UV dose over the range of germicidal doses tested (0.8-119 mJ/cm2). Oocyst inactivation increased rapidly with UV dose at doses less than 25 mJ/cm2 with two and three log-units inactivation at approximately 10 and 25 mJ/cm2, respectively. The cause of significant leveling-off and tailing in the UV inactivation curve at higher doses was not determined. Maximum measured oocyst inactivation ranged from 3.4 to greater than 4.9 log-units and was dependent on different batches of parasites. Water type and temperature, the concentration of oocysts in the suspension, and the UV irradiance did not have significant impacts on oocyst inactivation. When compared on the basis of germicidal UV dose, the oocysts were equally sensitive to low- and medium-pressure UV radiation. With respect to Cryptosporidium, both low- and medium-pressure ultraviolet radiation are attractive alternatives to conventional chemical disinfection methods in drinking water treatment.
Article
In drinking water treatment, the inactivation of microorganisms increases with increasing disinfectant exposure (product of concentration and contact time, CT). Also, the formation of undesired (toxic) disinfection by-products increases with CT. The present study proposes a new concept that uses this undesired side effect of chemical water disinfection for a fast and reliable test of treatment efficiency. In laboratory systems, bromate formation during ozonation and the formation of trihalomethanes during chlorination were used to calculate the disinfectant exposure, which is a measure for the achieved degree of disinfection.
Article
Fifteen chlorination by-products were analyzed in 416 water samples collected from 35 water treatment plants in Korea from 1996 to 1998. These samples were divided into five groups according to water sources (Han-river, Nakdong-river, Youngsan-river, Kum-river and Cheju) and detected CBPs were classified into six classes (trihalomethanes; THMs, haloacetic acids; HAAs, haloacetonitriles: HANs haloketones; HKs, chloralhydrate; CH, chloropicrin; CP) and then, it was observed the detection tendency and frequency of CBPs in each water source. The total concentration of CBPs in treated water from Nakdong-river or Han-river was higher than those from the other rivers. And the distribution pattern of each class of CBPs was similar in all water sources. THMs were the highest portion in the range of 40-50%, and HAAs and HANs were 28-35 and 9-15%, respectively. And there was a strong correlation between HANs and HKs (r=0.813). Each and total concentrations of CBPs showed to be more affected by the water source in two-way analysis of variance (two-way ANOVA) among the concentration of CBPs, the source of water and season.