Study of the potential health effects of disinfection by-products (trihalomethanes) in drinking water: A review

2019 ◽  
Author(s):  
Mohd Faizal Ab Jalil ◽  
Ain Nihla Kamarudzaman ◽  
Nasrul Hamidin ◽  
Ahmad Anas Nagoor Gunny
1997 ◽  
Vol 105 (1) ◽  
pp. 108-109 ◽  
Author(s):  
J Fawell ◽  
D Robinson ◽  
R Bull ◽  
L Birnbaum ◽  
G Boorman ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Glòria Carrasco-Turigas ◽  
Cristina M. Villanueva ◽  
Fernando Goñi ◽  
Panu Rantakokko ◽  
Mark J. Nieuwenhuijsen

Disinfection by-products (DBPs) are ubiquitous contaminants in tap drinking water with the potential to produce adverse health effects. Filtering and boiling tap water can lead to changes in the DBP concentrations and modify the exposure through ingestion. Changes in the concentration of 4 individual trihalomethanes (THM4) (chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)), MX, and bromate were tested when boiling and filtering high bromine-containing tap water from Barcelona. For filtering, we used a pitcher-type filter and a household reverse osmosis filter; for boiling, an electric kettle, a saucepan, and a microwave were used. Samples were taken before and after each treatment to determine the change in the DBP concentration. pH, conductivity, and free/total chlorine were also measured. A large decrease of THM4 (from 48% to 97%) and MX concentrations was observed for all experiments. Bromine-containing trihalomethanes were mostly eliminated when filtering while chloroform when boiling. There was a large decrease in the concentration of bromate with reverse osmosis, but there was a little effect in the other experiments. These findings suggest that the exposure to THM4 and MX through ingestion is reduced when using these household appliances, while the decrease of bromate is device dependent. This needs to be considered in the exposure assessment of the epidemiological studies.


2013 ◽  
Vol 7 (1) ◽  
pp. 128-144

Chlorination disinfection by-products (DBPs) are formed when water is chlorinated and the organic matter in the water reacts with chlorine to form these by-products. There have been concerns about the potential health effects of these by-products, including cancer and reproductive effects. Here we have reviewed the literature on reproductive health effects. Epidemiological studies on neural tube defects, urinary tract defects and small for gestation age/intra growth retardation have shown the most consistent statistically significant associations with an index of DBPs, but generally the risk estimates are small. The interpretation of the studies is not straight forward because they may not be directly comparable because of differences in DBP mixtures, exposure categories and actually uptake of DBPs due to differences in e.g. ingestion rates, showering, bathing, and swimming. Only few specific DBPs have been studied and THMs have often been used as a marker for other DBPs, since they are often routinely available. Sample sizes, and therefore power, have at times been low, particularly when the population was split into exposure categories. Although most studies considered some confounders, (residual) confounding by other water contaminants or other factors related to water intake, cannot always be excluded. Case ascertainment, for outcomes such as spontaneous abortion and certain congenital anomalies is far from straight forward, and for the latter at times anomalies are lumped together with different aetiology, which may be inappropriate. Furthermore, as with many reproductive epidemiological, if the putative agent affects both early pregnancy loss and later birth outcomes such as congenital anomalies, interpretation of later birth outcomes may be more difficult.


Author(s):  
Mark J. Nieuwenhuijsen ◽  
James Grellier ◽  
Rachel Smith ◽  
Nina Iszatt ◽  
James Bennett ◽  
...  

This paper summarizes the epidemiological evidence for adverse health effects associated with disinfection by-products (DBPs) in drinking water and describes the potential mechanism of action. There appears to be good epidemiological evidence for a relationship between exposure to DBPs, as measured by trihalomethanes (THMs), in drinking water and bladder cancer, but the evidence for other cancers including colorectal cancer is inconclusive and inconsistent. There appears to be some evidence for an association between exposure to DBPs, specifically THMs, and little for gestational age/intrauterine growth retardation and, to a lesser extent, pre-term delivery, but evidence for relationships with other outcomes such as low birth weight, stillbirth, congenital anomalies and semen quality is inconclusive and inconsistent. Major limitations in exposure assessment, small sample sizes and potential biases may account for the inconclusive and inconsistent results in epidemiological studies. Moreover, most studies have focused on total THMs as the exposure metric, whereas other DBPs appear to be more toxic than the THMs, albeit generally occurring at lower levels in the water. The mechanisms through which DBPs may cause adverse health effects including cancer and adverse reproductive effects have not been well investigated. Several mechanisms have been suggested, including genotoxicity, oxidative stress, disruption of folate metabolism, disruption of the synthesis and/or secretion of placental syncytiotrophoblast-derived chorionic gonadotropin and lowering of testosterone levels, but further work is required in this area.


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