Trihalomethanes in the drinking water of Concepción and Talcahuano, Chile

Abstract

Formation of trihalomethanes (THMs) during water disinfection has been related to several health problems, although the magnitude of these effects is under discussion. This paper quantifies the THMs in drinking water from the Bío-Bío Region of central Chile, the first since the modification of the national reference value (Nch 409/05) to include maximal values for THMs. THMs were quantified using a solid phase micro-extraction (SPME) method and GC-MS. The concentration ranges were 9.7-111.6, 0.1-1.0 and 0.9-25.5 mg/L for chloroform (CHCl 3 ), and dibromochloromethane (CHClBr 2 ) and bromodichloromethane (CHCl 2 Br), respectively. Bromoform was not detected in any sample. There were good correlations (R 2 =0.91-0.98, Po0.001) between the THMs and the residence time of the water, the distance from the treatment plant and an inverse correlation to free chlorine in the water. The Additive Toxicity Index Value (0.07-1.00) showed that all samples were within the Chilean reference value for THMs in drinking water. However, several values were close to exceeding the maximum permitted concentration (200, 100, 100 and 60 mg/L for CHCl 3 , CHBr 3 , CHClBr 2 and CHCl 2 Br, respectively), which may occur when the water demand is low and thus residence times are longer.

Household Cleaning Activities as Noningestion Exposure Determinants of Urinary Trihalomethanes

“…This finding corroborates engineering trends linking higher water residence time into pipes with enhanced THM formation potential. 26,33,34 The significant (p = 0.01) negative influence of water THM concentrations on urinary TTHM levels was driven by water THM concentrations being >75th percentile (>83 μg L −1 ). No associations were observed between per capita water consumption rates and urinary TTHM for those participants using: (i) only tap (n = 21, 6%) (r S = −0.14, p = 0.54), (ii) water sources other than tap (bottled water and mobile station water) (n = 90, 28%) (r S = −0.11, p = 0.29), and (iii) both tap and other water sources (n = 214, 66%) (r S = 0.13, p = 0.06) (Figure S5, Supporting Information).…”

“…Internal THM exposure measurements in biofluids may often be complicated, given the volatile nature of THM, rapid metabolic turnover, and/or the random THM loss via exhalation in studies using blood and exhaled breath as biomarkers of THM exposures. , Though short-lived (<1 h), a noticeable correlation exists between measured blood and urinary THM concentrations, which fall within the sub μg L –1 range for both biomarkers. Urinary THM measurements have been used in exposure studies involving swimmers in indoor swimming pools .…”

Spatial and seasonal variability of tap water disinfection by-products within distribution pipe networks

“…A few studies have investigated the effect of household variability on water THM levels within a specific DMA and its pipe network features. Loyola-Sepulveda et al (2009) showed a significant positive correlation between household water THM levels and residence time and distance from the point of entry, and a significant negative correlation with free residual chlorine. By sampling water from washroom faucets in commercial buildings with increasing distance (km) from the water utility, an increase up to 2.5 times in water THM levels was documented (Rodriguez et al, 2003).…”

“…It is only during the last couple of decades that the structural integrity and characteristics of piped UDWDS are studied together with the formation of THM in tap water, including, the size of UDWDS (Dion-Fortier et al, 2009) and the duration of water stagnation (Sadiq and Rodriguez, 2004). Most of field studies collected water samples along the UDWDS (Rodriguez et al, 2003;Pereira et al, 2004;Mouly et al, 2010), while a few of them sampled directly at the points of use in households with a limited number of sampling points (17 households by Symanski et al (2004); 6 houses by Loyola-Sepulveda et al (2009)). Other pertinent field studies considered (i) a limited number of sampled points (>3) along a UDWDS (LeBel et al, 1996), (ii) the effect of water residence time on water DBP levels (Chen and Weisel, 1998), (iii) the selection of sampling points based on distances from the water treatment plants (Baytak et al, 2008), and (iv) the influence of hydraulic parameters (LeBel et al, 1996).…”

Drinking Water and Human Health Challenges in the Twenty‐First Century

“…It is only during the last couple of decades that the structural integrity and characteristics of piped UDWDS are studied along with the formation of THM in tap water, including, the size of UDWDS [60] and the duration of water stagnation [61]. Most of field studies collected water samples along the UDWDS [62][63][64], while a few of them sampled directly at the points of use in households with a limited number of sampling points (17 households, [65]; 6 houses [66]). Other pertinent field studies considered a limited number of sampled points (>3) along a UDWDS [67], the effect of water residence time on water DBP levels [68], the selection of sampling points based on distances from the water treatment plants [69], and the influence of hydraulic parameters [67].…”