Y Kimura S, Zheng W, N Hipp T, M Allen J, D Richardson S. Total organic halogen (TOX) in human urine: A halogen-specific method for human exposure studies. Journal of environmental sciences (China). 2017 Aug;58:285-295. doi: 10.1016/j.jes.2017.04.008.
Disinfection by-products (DBPs) are a complex mixture of compounds unintentionally formed as a result of disinfection processes used to treat drinking water. Effects of long-term exposure to DBPs are mostly unknown and were the subject of recent epidemiological studies. However, most bioanalytical methods focus on a select few DBPs. In this study, a new comprehensive bioanalytical method has been developed that can quantify mixtures of organic halogenated compounds, including DBPs, in human urine as total organic chlorine (TOCl), total organic bromine (TOBr), and total organic iodine (TOI). The optimized method consists of urine dilution, adsorption to activated carbon, pyrolysis of activated carbon, absorption of gases in an aqueous solution, and halide analysis with ion chromatography and inductively coupled plasma-mass spectrometry. Spike recoveries for TOCl, TOBr, and TOI measurements ranged between 78% and 99%. Average TOCl, TOBr, and TOI concentrations in five urine samples from volunteers who consumed tap water were 1850, 82, and 21.0μg/L as X–, respectively. Volunteers who consumed spring water (control) had TOCl, TOBr, and TOI average concentrations in urine of 1090, 88, and 10.3μg/L as X–, respectively. TOCl and TOI in the urine samples from tap water consumers were higher than the control. However, TOBr was slightly lower in tap water urine samples compared to mineral water urine samples, indicating other sources of environmental exposure other than drinking water. A larger sample population that consumes tap water from different cities and mineral water is needed to determine TOCl, TOBr, and TOI exposure from drinking water.
Zhang Y, Chu W, Yao D, Yin D. Control of aliphatic halogenated DBP precursors with multiple drinking water treatment processes: Formation potential and integrated toxicity. J Environ Sci (China). 2017 Aug;58:322-330. doi: 10.1016/j.jes.2017.03.028.
The comprehensive control efficiency for the formation potentials (FPs) of a range of regulated and unregulated halogenated disinfection by-products (DBPs) (including carbonaceous DBPs (C-DBPs), nitrogenous DBPs (N-DBPs), and iodinated DBPs (I-DBPs)) with the multiple drinking water treatment processes, including pre-ozonation, conventional treatment (coagulation-sedimentation, pre-sand filtration), ozone-biological activated carbon (O3-BAC) advanced treatment, and post-sand filtration, was investigated. The potential toxic risks of DBPs by combing their FPs and toxicity values were also evaluated. The results showed that the multiple drinking water treatment processes had superior performance in removing organic/inorganic precursors and reducing the formation of a range of halogenated DBPs. Therein, ozonation significantly removed bromide and iodide, and thus reduced the formation of brominated and iodinated DBPs. The removal of organic carbon and nitrogen precursors by the conventional treatment processes was substantially improved by O3-BAC advanced treatment, and thus prevented the formation of chlorinated C-DBPs and N-DBPs. However, BAC filtration leads to the increased formation of brominated C-DBPs and N-DBPs due to the increase of bromide/DOC and bromide/DON. After the whole multiple treatment processes, the rank order for integrated toxic risk values caused by these halogenated DBPs was haloacetonitriles (HANs)≫haloacetamides (HAMs)>haloacetic acids (HAAs)>trihalomethanes (THMs)>halonitromethanes (HNMs)≫I-DBPs (I-HAMs and I-THMs). I-DBPs failed to cause high integrated toxic risk because of their very low FPs. The significant higher integrated toxic risk value caused by HANs than other halogenated DBPs cannot be ignored.
Allen JM, Cuthbertson AA, Liberatore HK, Kimura SY, Mantha A, Edwards MA, Richardson SD. Showering in Flint, MI: Is there a DBP problem? J Environ Sci (China). 2017 Aug;58:271-284. doi: 10.1016/j.jes.2017.06.009.
Lead contamination in the City of Flint, MI has been well documented over the past two years, with lead levels above the EPA Action Level until summer 2016. This resulted from an ill-fated decision to switch from Detroit water (Lake Huron) with corrosion control, to Flint River water without corrosion control. Although lead levels are now closer to normal, reports of skin rashes have sparked questions surrounding tap water in some Flint homes. This study investigated the presence of contaminants, including disinfection by-products (DBPs), in the hot tap water used for showering in the homes of residents in Flint. Extensive quantitative analysis of 61 regulated and priority unregulated DBPs was conducted in Flint hot and cold tap water, along with the analysis of 50 volatile organic compounds and a nontarget comprehensive, broadscreen analysis, to identify a possible source for the reported skin rashes. For comparison, chlorinated hot and cold waters from three other cities were also sampled, including Detroit, which also uses Lake Huron as its source water. Results showed that hot water samples generally contained elevated levels of regulated and priority unregulated DBPs compared to cold water samples, but trihalomethanes were still within regulatory limits. Overall, hot shower water from Flint was similar to waters sampled from the three other cities and did not have unusually high levels of DBPs or other organic chemicals that could be responsible for the skin rashes observed by residents. It is possible that an inorganic chemical or microbial contaminant may be responsible.
Nie X, Liu W, Zhang L, Liu Q. Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test. Journal of environmental sciences (China). 2017 Jun;56:36-44. doi: 10.1016/j.jes.2016.07.016.
The genotoxicity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the umu-test. The pretreatment procedure of samples for the umu-test was optimized for drinking water analysis. The results of the umu-test were in good correlation with those of the Ames-test. The genotoxicity and production of haloacetic acids (HAAs) were the highest for chlorinated samples. UV+chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of Cl2 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks.
Parvez S, Frost K, Sundararajan M. Evaluation of Drinking Water Disinfectant Byproducts Compliance Data as an Indirect Measure for Short-Term Exposure in Humans. Int J Environ Res Public Health. 2017 May 20;14(5). pii: E548. doi: 10.3390/ijerph14050548.
In the absence of shorter term disinfectant byproducts (DBPs) data on regulated Trihalomethanes (THMs) and Haloacetic acids (HAAs), epidemiologists and risk assessors have used long-term annual compliance (LRAA) or quarterly (QA) data to evaluate the association between DBP exposure and adverse birth outcomes, which resulted in inconclusive findings. Therefore, we evaluated the reliability of using long-term LRAA and QA data as an indirect measure for short-term exposure. Short-term residential tap water samples were collected in peak DBP months (May-August) in a community water system with five separate treatment stations and were sourced from surface or groundwater. Samples were analyzed for THMs and HAAs per the EPA (U.S. Environmental Protection Agency) standard methods (524.2 and 552.2). The measured levels of total THMs and HAAs were compared temporally and spatially with LRAA and QA data, which showed significant differences (p < 0.05). Most samples from surface water stations showed higher levels than LRAA or QA. Significant numbers of samples in surface water stations exceeded regulatory permissible limits: 27% had excessive THMs and 35% had excessive HAAs. Trichloromethane, trichloroacetic acid, and dichloroacetic acid were the major drivers of variability. This study suggests that LRAA and QA data are not good proxies of short-term exposure. Further investigation is needed to determine if other drinking water systems show consistent findings for improved regulation.
Al-Otoum F, Al-Ghouti MA, Ahmed TA, Abu-Dieyeh M, Ali M. Disinfection by-products of chlorine dioxide (chlorite, chlorate, and trihalomethanes): Occurrence in drinking water in Qatar. Chemosphere. 2016 Sep 13;164:649-656. doi: 10.1016/j.chemosphere.2016.09.008.
The occurrence of chlorine dioxide (ClO2) disinfection by-products (DBPs) in drinking water, namely, chlorite, chlorate, and trihalomethanes (THMs), was investigated. Two-hundred-ninety-four drinking water samples were collected from seven desalination plants (DPs), four reservoirs (R), and eight mosques (M) distributed within various locations in southern and northern Qatar. The ClO2 concentration levels ranged from 0.38 to <0.02 mg L-1, with mean values of 0.17, 0.12, and 0.04 mg L-1 for the DPs, Rs, and Ms, respectively. The chlorite levels varied from 13 μg L-1 to 440 μg L-1, with median values varying from 13 to 230 μg L-1, 77-320 μg L-1, and 85-440 μg L-1 for the DPs, Rs, and Ms, respectively. The chlorate levels varied from 11 μg L-1 to 280 μg L-1, with mean values varying from 36 to 280 μg L-1, 11-200 μg L-1, and 11-150 μg L-1 in the DPs, Rs, and Ms, respectively. The average concentration of THMs was 5 μg L-1, and the maximum value reached 77 μg L-1 However, all of the DBP concentrations fell within the range of the regulatory limits set by GSO 149/2009, the World Health Organization (WHO), and Kahramaa (KM).
Shen H, Chen X, Chen H. Influence on the generation of disinfection byproducts in a tannic acid solution by aluminum ions. Environmental Technology. 2016 Aug 17:1-11.
Aluminum (Al) commonly exists in natural waters, and its salts are often used as coagulants in drinking water treatment. Therefore, associated with the security of drinking water, functions of Al ions (Al3+) on generation of disinfection byproducts (DBPs) should not be ignored. This study focuses on DBPs and the carcinogenic factor of chlorinated water samples after the addition of Al3+ with different Al3+/initial tannic acid molar ratios. The results imply that Al3+ acts as a promoter of haloacetic acids (HAAs) and an inhibitor of trihalomethanes (THMs) when tannic acid is selected as model compound of natural organic matter during chlorination. Depending on the results of size exclusion chromatography and ultraviolet spectrophotometer, an equilibrium system can be assumed between hydrolysis and flocculation in tannic acid solution with Al3+. Furthermore, influences on the equilibrium system for Al3+ addition may result in various effects on generation and distribution ratios of THMs and HAAs during chlorination. Finally, according to the analyses of a fluorescence spectrophotometer, it is demonstrated that the presence of Al3+helps to increase precursors of DBPs (humic acid-like organics) and then improve the generation of DBPs.