Disinfection Byproduct Formation and Fractionation Behavior of Natural Organic Matter Surrogates

While natural organic matter (NOM) surrogates are established in disinfection byproduct (DBP) research, their use in fractionation studies is rare. To understand how surrogates relate to drinking waters, a range of NOM surrogates were fractionated with XAD resins. Their trihalomethane (THM), haloacetic acid (HAA), haloacetaldehyde, haloacetonitrile, and haloketone formations after chlorination were recorded. While compounds with higher log KOW values behaved as hydrophobic acids, fractionation of the more hydrophilic compounds did not clearly correlate to the log KOW. High HAA formation from ferulic and aspartic acids and 1,1,1-trichloropropanone (1,1,1-TCP) formation from 3-oxopropanoic acid were notable. Three amino acids, asparagine, aspartic acid, and tryptophan, formed significant levels of dichloroacetonitrile (DCAN) and trichloroacetaldehyde (TCA). Formation of DBPs did not correlate to any compound physical property; however, there were several correlations between DBP groups. The most significant were between dichloroacetic acid (DCAA) and dichloroacetonitrile (DCAN), DCAN and TCA, and dichloroacetaldehyde (DCA) and trichloroacetaldehyde, indicating the possibility of similar relationships in natural waters

Characterization of the Molecular Weight and Reactivity of Natural Organic Matter in Surface Waters

Natural organic matter (NOM) can impact on all aspects of water treatments processes. Understanding the physical and chemical characteristics of NOM is essential to improving drinkingwater treatment processes. The size of NOM has important implications for drinking water treatment and the formation of DBPs, where the high molecular weight, hydrophobic components of NOM have been found to be effectively removed by conventional drinking water treatment processes, while the lower molecular weight and certain hydrophilic components of NOM are more difficult to remove using these processes. In our study, we collected raw (untreated) watersfrom three different drinking water reservoirs, characterised the molecular weight (MW) distribution of the NOM in these waters using analytical scale high performance size exclusion chromatography (HPSEC), and isolated apparent MW (AMW) fractions of the NOM using preparative scale HPSEC. We also investigated the reactivity of the AMW fractions of NOM interms of disinfection by-products (DBP) formation potential from chlorination and chloramination. We focused on the formation potential of halogen-specific adsorbable organic halogen (AOX) and nitrogen-containing DBPs (N-DBPs), since brominated and iodinated DBPs and N-DBPs have beenreported to be significantly more cytotoxic, genotoxic, and carcinogenic than the regulated DBPs. Our study found that the AMW fractions of NOM with higher SUVA254 values generally produced higher concentrations of halogenated DBPs, measured as halogen-specific AOX. Halogenated N-DBPs formed only a small fraction of AOX in both chlorination and chloramination, with higher relative contributions from halogenated N-DBPs in chloraminated samples. The propensity of the formation of N-DBPs, especially N-nitrosamines and haloacetamides, was higher in chloramination. Since these DBPs are more toxic than the regulated DBPs, further evaluation of the health risk trade-offs when selecting chlorine or chloramine as a disinfectant is essential. The size of NOM had little influence on the formation of halogenated N-DBPs, but the low to medium AMW fractions of NOM tended to form higher concentrations of N-nitrosamines. Chlorine tended to be incorporated into the higher AMW fractions of NOM, while bromine and iodine seemed to be preferentially incorporated into the lower AMW fractions of NOM. Since conventional water treatment processes are ineffective for the removal of the low to medium MW fractions of NOM, improved water treatment processes may be needed to minimise the formation of brominated andiodinated DBPs, as well as N-nitrosamines, especially for source waters that contain significant amounts of organic matter of low to medium MW

History trials: notes on law, history, and time

This article examines the relationship between law and historiography. Law played a central role in the creation of the nation-state. Historiography also narrates the victories and sacrifices of the nation and constructs its “imagined community.” Recently, court hearings are increasingly used for history authentication. Developing Hannah Arendt's argument in Eichmann in Jerusalem, the article argues that legal proceedings are not suitable for clarifying the historical record

Trihalomethanes in drinking water and bladder cancer burden in the European Union

Abstract Background: Trihalomethanes (THMs) are widespread disinfection by-products (DBPs) in drinking water, and long-term exposure has been consistently associated with increased bladder cancer risk. Objective: We assessed THM levels in drinking water in the European Union as a marker of DBP exposure and estimated the attributable burden of bladder cancer. Methods: We collected recent annual mean THM levels in municipal drinking water in 28 European countries (EU28) from routine monitoring records. We estimated a linear exposure–response function for average residential THM levels and bladder cancer by pooling data from studies included in the largest international pooled analysis published to date in order to estimate odds ratios (ORs) for bladder cancer associated with the mean THM level in each country (relative to no exposure), population-attributable fraction (PAF), and number of attributable bladder cancer cases in different scenarios using incidence rates and population from the Global Burden of Disease study of 2016. Results: We obtained 2005–2018 THM data from EU26, covering 75% of the population. Data coverage and accuracy were heterogeneous among countries. The estimated population-weighted mean THM level was 11.7μg/L [standard deviation (SD) of 11.2]. The estimated bladder cancer PAF was 4.9% [95% confidence interval (CI): 2.5, 7.1] overall (range: 0–23%), accounting for 6,561 (95% CI: 3,389, 9,537) bladder cancer cases per year. Denmark and the Netherlands had the lowest PAF (0.0% each), while Cyprus (23.2%), Malta (17.9%), and Ireland (17.2%) had the highest among EU26. In the scenario where no country would exceed the current EU mean, 2,868 (95% CI: 1,522, 4,060; 43%) annual attributable bladder cancer cases could potentially be avoided. Discussion: Efforts have been made to reduce THM levels in the European Union. However, assuming a causal association, current levels in certain countries still could lead to a considerable burden of bladder cancer that could potentially be avoided by optimizing water treatment, disinfection, and distribution practices, among other possible measures

Occurrence and toxicity of disinfection byproducts in European drinking waters in relation with the HIWATE epidemiology study

The HIWATE (Health Impacts of long-term exposure to disinfection byproducts in drinking WATEr) project was a systematic analysis that combined the epidemiology on adverse pregnancy outcomes and other health effects with long-term exposure to low levels of drinking water disinfection byproducts (DBPs) in the European Union. The present study focused on the relationship of the occurrence and concentration of DBPs with in vitro mammalian cell toxicity. Eleven drinking water samples were collected from five European countries. Each sampling location corresponded with an epidemiological study for the HIWATE program. Over 90 DBPs were identified; the range in the number of DBPs and their levels reflected the diverse collection sites, different disinfection processes, and the different characteristics of the source waters. For each sampling site, chronic mammalian cell cytotoxicity correlated highly with the numbers of DBPs identified and the levels of DBP chemical classes. Although there was a clear difference in the genotoxic responses among the drinking waters, these data did not correlate as well with the chemical analyses. Thus, the agents responsible for the genomic DNA damage observed in the HIWATE samples may be due to unresolved associations of combinations of identified DBPs, unknown emerging DBPs that were not identified, or other toxic water contaminants. This study represents the first to integrate quantitative in vitro toxicological data with analytical chemistry and human epidemiologic outcomes for drinking water DBPs