This study investigates the relationship between storm-driven changes in natural organic matter (NOM) and disinfection byproduct (DBP) formation. The novel framework presented correlates specific differential absorbance at 254 nm (Sp-ΔUV254), which measures the change in UV254 due to chlorination normalized by initial dissolved organic carbon (DOC) concentration, with critical water quality parameters such as chlorine demand, DBP formation, size-fractionated NOM, and lignin to enhance mechanistic understandings of DBP precursor dynamics. To evaluate the impact of a storm on the DBP precursor dynamics, samples were collected from the Neversink River (NY) during a high-flow event. The formation of total trihalomethanes (THMs), or specific trihalomethanes (Sp-THM) when normalized by initial DOC, strongly correlated to Sp-ΔUV254. The pre- and postchlorinated samples' quotients of absorbances at 250 and 365 nm (E2/E3) yielded a strong correlation despite a decreased ΔUV254 due to chlorination, suggesting dissolved organic matter transformation to less aromatic structures, in agreement with size exclusion chromatography (SEC) data. A novel SEC-DOC technique showed THM precursors increased during the rising limb of the storm with a predominant molecular weight range of 2000-10,000 Da. Stable water isotope (δ18O) measurements suggest quick mobilization of stored NOM accumulated in the watershed, which was also supported by quantified lignin concentrations.

The Neversink Reservoir watershed, an important contributor to New York City's drinking water supply, was sampled over the summer of 2022 to investigate the spatiotemporal variability of dissolved organic matter (DOM) and disinfection byproducts (DBP) potential (e.g., dichloroacetic acids (DCAAs), trichloroacetic acids (TCAAs), trihalomethane (THM)) and their relationship to geomorphic features (e.g., topographic indices (TI), drainage area, and runoff patterns) under baseflow conditions. Eleven sub-basins were monitored for fluorescent DOM, dissolved organic carbon (DOC), fluorescence index, specific ultraviolet absorbance at 254 nm (SUVA), turbidity, and DBP formation potential. Results showed that DOM was primarily aromatic, chromophoric, and mostly derived from terrestrial sources with DOC means ranging spatially from 0.83 to 1.38 mg/L. DBP potential concentrations varied more spatially (43 to 157 mu g/L for TCAA) than over time (23.9 to 48 mu g/L for TCAA at the Main Branch). Drainage area and topographic index explained differences in DOC means (R-2 = 0.41, R-2 = 0.87) and SUVA means (R-2 = 0.48, R-2 = 0.59) across sub-basins and had moderate explanatory power for specific DBP precursor concentrations (R-2 = 0.05 to R-2 = 0.49). TI showed the strongest relationship with DOC (R = -0.93) and SUVA (R = -0.77) with an inverse relationship that has not been commonly observed but is present in similar hardwood forested watersheds.

Characteristics of intermittent piped water supply, in which the distribution system is not continuously pressurized, can allow contamination to enter pipes as intrusion. Two source waters were chlorinated and dosed with synthetic and real wastewater to simulate intrusion into a pipe with stagnant water to measure its impact on DBP formation potential. The formation and speciation of DBPs, including trihalomethanes, haloacetic acids, and haloacetonitriles, were measured throughout 7-day long experiments. Concentrations of regulated DBPs were greatest in experiments with either no intrusion or in experiments simulating intrusion of synthetic wastewater that lacked known chloramine-forming compounds. Intrusion from real and synthetic wastewater with chloramine-forming compounds quickly quenched existing free chlorine residual, limiting reactions with chlorine throughout the rest of the experiment. However, we observed up to 3.8 times greater dichloroacetonitrile concentrations 30 minutes following modified synthetic intrusion than pre-intrusion concentrations, compared to only a slight increase with no intrusion. After intrusion, regulated DBPs accounted for 77.9–92.6% of the total mass concentrations of DBPs measured in this study yet only accounted for 8.9–71.4% of the calculated additive cytotoxicity. In this study, we demonstrate that wastewater intrusion into a drinking water distribution system during stagnation likely leads to the formation of chloramine compounds if free chlorine is available. Certain types of intrusion, particularly with waters that do not contain chloramine-forming compounds, may increase overall DBP formation and is particularly pronounced for nonregulated haloacetonitriles, which contribute a greater effect on overall toxicity than currently regulated DBPs. These findings justify future work regarding the water safety impacts of wastewater intrusion, particularly increased DBP-attributed toxicity and haloacetonitrile formation, highlighting the need for strategic interventions to protect chemical drinking water quality in piped water systems with intermittent supplies or those that are vulnerable to outages.

Haloacetonitriles (HANs) are unregulated nitrogenous disinfection byproducts (N-DBPs) widely distributed in drinking water distribution systems. These N-DBPs originate from the reaction of organic precursors and disinfectants including chlorine, chloramine, or chlorine dioxide. This study was aimed at determining HAN yields from model organic compounds under both chlorination and chloramination conditions by laboratory studies. The specific conditions selected (i.e., doses, sequence, pH, reaction times) were intended to create chemical environments that are similar to those that exist in drinking water treatment systems. Precursor compounds selected for study included some key biochemicals known to be present in drinking waters. Results of these laboratory experiments are presented in the form of molar yields for specific precursor compounds, and some were mathematically compensated for excessive HAN degradation during laboratory testing. Model compound data clearly showed aspartic acid to be the most productive dihaloacetonitrile (DHAN) precursor tested. This compound in its free state has the potential to add substantially to a water's DHAN formation under free chlorination. There are other amino acids, such as histidine and asparagine that may contribute, but these are probably secondary to aspartic acid. While proteins or polypeptides are far less reactive with free chlorine as compared to free amino acids, their greater abundance makes them potential important members of the DHAN precursor pool. In contrast, nucleic acids appear to be relatively insignificant as DHAN precursors. There are other potential precursors such as aromatic amines (i.e., 3-aminophenol), and even some hydroxylated aliphatic amines (i.e., 4-amino-2-hydroxybutyric acid), that could be significant contributors under free chlorination conditions. This study showed that DHAN formation in systems using chloramines depends strongly on the pre‑chlorine contact time. Unlike free chlorine systems, lignin and lignin phenols may be significant DHAN precursors when chloramines are used. Organic amines, such as aspartic acid and asparagine may also contribute as important precursors in chloramination systems.

BACKGROUND:Some disinfection byproducts (DBPs) are teratogens based on toxicological evidence. Conventional use of predominant DBPs as proxies for complex mixtures may result in decreased ability to detect associations in epidemiological studies.OBJECTIVE:We assessed risks of obstructive genitourinary birth defects (OGDs) in relation to 12 DBP mixtures and 13 individual component DBPs.METHODS:We designed a nested registry-based case-control study (210 OGD cases; 2100 controls) in Massachusetts towns with complete quarterly 1999-2004 data on four trihalomethanes (THMs) and five haloacetic acids (HAAs). We estimated temporally-weighted average DBP exposures for the first trimester of pregnancy. We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for OGD in relation to individual DBPs, unweighted mixtures, and weighted mixtures based on THM/HAA relative potency factors (RPF) from animal toxicology data for full-litter resorption, eye defects, and neural tube defects.RESULTS:We detected elevated aORs for OGDs for the highest of bromodichloromethane (aOR = 1.75; 95% CI: 1.15-2.65), dibromochloromethane (aOR = 1.71; 95% CI: 1.15-2.54), bromodichloroacetic acid (aOR = 1.56; 95%CI: 0.97-2.51), chlorodibromoacetic acid (aOR = 1.97, 95% CI: 1.23-3.15), and tribromoacetic acid (aOR = 1.90; 95%CI: 1.20-3.03). Across unweighted mixture sums, the highest aORs were for the sum of three brominated THMs (aOR = 1.74; 95% CI: 1.15-2.64), the sum of six brominated HAAs (aOR = 1.43; 95% CI: 0.89-2.31), and the sum of nine brominated DBPs (aOR = 1.80; 95% CI: 1.05-3.10). Comparing eight RPF-weighted to unweighted mixtures, the largest aOR differences were for two HAA metrics, which both were higher with RPF weighting; other metrics had reduced or minimally changed ORs in RPF-weighted models.

Small drinking water systems in the United States often suffer from repeated Safe Drinking Water Act water quality violations that necessitate upgrades to the existing centralized systems to achieve compliance. Community water systems (CWSs) need to evaluate the tradeoffs between public health, environmental and economic impacts when choosing these system improvements. This study developed the input and output components of a triple-bottom-line methodology to compare two alternatives: (1) installing a centralized treatment upgrade or (2) a point-of-use/point-of-entry device over a 30-year period, using a health exposure assessment specific contaminants, life cycle analysis of environmental impacts improvement, and life cycle costing to account for the useful life of components and the number of households served by a CWS. We present recommendations and considerations for future usage of the triple-bottom-line approach methodology.

Intermittent water supply (IWS) is found in many parts of the world, especially in low- and middle-income regions, and is characterized by a loss of distribution system pressure, periods of stagnation, the intrusion of contaminants, repressurization of the piped system when service is resumed after a no-supply period, and the need for consumer water storage. Although we have a robust understanding of the impacts of IWS on microbial water quality, less research emphasis has been placed on the impact of intermittency on chemical water quality, such as the formation of disinfection byproducts (DBPs). Chemical disinfection is commonly used to remove or inactivate waterborne pathogens during drinking water treatment and distribution to protect and improve microbial water quality. However, characteristics of IWS have known or suspected contributions to factors that impact DBP formation during drinking water distribution and household storage, such as the intrusion of organic matter, variable post-chlorine water ages, and growth and/or regrowth of microbial communities. This review discusses the impact of IWS on the formation and fate of DBPs, drawing upon the literature regarding continuous water supply systems and key characteristics of IWS. We call for more frequent monitoring of DBPs in IWS and further investigation of the mechanisms affecting DBP formation and speciation under various IWS conditions.

The U.S. Environmental Protection Agency (EPA) is considering a regulatory revision of the Disinfectant and Disinfection Byproduct Rule (DBPR) with a goal of limiting nationwide exposure to DBPs of emerging health concern. The occurrence of four brominated haloacetic acids (HAAs), which are generally more toxic in in vitro assays than the five currently regulated HAAs and are candidates for future regulation, were surveyed in 4924 public water systems under EPA's fourth unregulated contaminant monitoring rule (UCMR4). Using UCMR4 data, this study evaluated the nationwide occurrence of nine HAA species and the potential for two regulatory scenarios (the mass sum of all nine HAA species, HAA9, or just the six brominated HAA species, HAA6Br) to control nationwide exposure to the most toxic HAAs. Neither HAA9 nor HAA6Br approaches were effective for identifying water systems that exhibit high HAA exposure, assessed as additive cytotoxicity, because they are more specific to the HAA species that form at high concentrations rather than the species that are most toxic. However, the effectiveness of HAA6Br is highly sensitive to the relative toxicity of one HAA compound, monobromoacetic acid, which has the highest in vitro toxicity among HAAs but also the lowest occurrence and about which little is known regarding in vivo health risks. In contrast to HAA9, systems with high HAA-associated additive toxicity tend to share similar treatment and disinfectant characteristics as systems with high HAA6Br concentrations. Systems with high source water bromide and total organic carbon were far more likely to use chloramines as a disinfectant residual compared to other systems, but were no more likely to adopt organic precursor removal technologies (biofiltration, granular activated carbon, and ion exchange) than other systems, on average.

Rainwater collection systems often include a first flush volume to divert contaminants away from collected and stored rainwater. These have traditionally been designed for a set volume, to capture and divert the first 1-2 mL of rain deposited onto a roof. However, environmental and collection system parameters can vary the volume of the first flush necessary to effectively divert contaminants. Using a test-scale rainwater collection system in Amherst, Massachusetts (USA), a series of experiments were conducted to assess the quality of rainwater in the system per collection volume and time. This included a tracer study of an ideal contaminant, water quality measurements of atmospheric rain, fractionated first flush, and the collection tank during rain events. First flush samples contained elevated dissolved organic carbon (DOC) concentrations up to 40 mg/L, with high variability between the rain events. UV 254, DOC, and conductivity all trended together indicating a uniform wash-off of contaminants. Higher intensity storms increased roof wash-off deposition and environmental conditions affected the necessary first flush volumes. The majority of contaminants likely originated from roof wet and dry deposition. The design of first flush in rainwater harvesting systems needs to account for local precipitation patterns, storm intensity, and canopy conditions.

Background: Trihalomethanes (THM), a major class of disinfection by-products, are widespread and are associ-ated with adverse health effects. We conducted a global evaluation of current THM regulations and concen-trations in drinking water. Methods: We included 120 countries (-7000 million inhabitants in 2016), representing 94% of the world pop-ulation. We searched for country regulations and THM routine monitoring data using a questionnaire addressed to referent contacts. Scientific and gray literature was reviewed where contacts were not identified or declined participation. We obtained or estimated annual average THM concentrations, weighted to the population served when possible. Results: Drinking water regulations were ascertained for 116/120 (97%) countries, with 89/116 (77%) including THM regulations. Routine monitoring was implemented in 47/89 (53%) of countries with THM regulations. THM data with a varying population coverage was obtained for 69/120 (58%) countries consisting of-5600 million inhabitants (76% of world's population in 2016). Population coverage was >= 90% in 14 countries, mostly in the Global North, 50-89% in 19 countries, 11-49% among 21 countries, and <= 10% in 14 countries including India, China, Russian Federation and Nigeria (40% of world's population). Discussion: An enormous gap exists in THM regulatory status, routine monitoring practice, reporting and data availability among countries, especially between high-vs. low-and middle-income countries (LMICs). More efforts are warranted to regulate and systematically assess chemical quality of drinking water, centralize, harmonize, and openly report data, particularly in LMICs.

Many challenges remain before we can fully understand the multifaceted role that natural organic matter (NOM) plays in soil and aquatic systems. These challenges remain despite the considerable progress that has been made in understanding NOM’s properties and reactivity using the latest analytical techniques. For nearly 4 decades, the International Humic Substances Society (IHSS, which is a non-profit scientific society) has distributed standard substances that adhere to strict isolation protocols and reference materials that are collected in bulk and originate from clearly defined sites. These NOM standard and reference samples offer relatively uniform materials for designing experiments and developing new analytical methods. The protocols for isolating NOM, and humic and fulvic acid fractions of NOM utilize well-established preparative scale column chromatography and reverse osmosis methods. These standard and reference NOM samples are used by the international scientific community to study NOM across a range of disciplines from engineered to natural systems, thereby seeding the transfer of knowledge across research fields. Recently, powerful new analytical techniques used to characterize NOM have revealed complexities in its composition that transcend the “microbial” vs. “terrestrial” precursor paradigm. To continue to advance NOM research in the Anthropocene epoch, a workshop was convened to identify potential new sites for NOM samples that would encompass a range of sources and precursor materials and would be relevant for studying NOM’s role in mediating environmental and biogeochemical processes. We anticipate that expanding the portfolio of IHSS reference and standard NOM samples available to the research community will enable this diverse group of scientists and engineers to better understand the role that NOM plays globally under the influence of anthropogenic mediated changes.

Tropane alkaloids (TA) are compounds widespread in the Solanaceae family. The genera Atropa, Brugmansia, Hyoscyamus, and Scopolia, produce the pharmaceuticals hyoscyamine (Hy) and scopolamine (Sc), which are valued for their antimuscarinic and anticholinergic actions. The enzyme hyoscyamine 6β-hydroxylase (H6H) (EC 1.14.11.11) catalyzes both the hydroxylation of hyoscyamine to 6β-hydroxyhyoscyamine and the epoxidation of the latter, leading to scopolamine (Hashimoto et al. 1993). During the examination of three genes in the TA biosynthetic pathway, the first committed step, the path branch point, and the final step in 13 accessions of Hyoscyamus niger from North America and Europe, genetic variations were found to be absent except in the h6h gene locus (GenBank: D26583.1). Quantification of TA showed average concentrations of 26 to 520 μg/g of dry leaf tissue among the accessions. From a monohybrid cross of the expected (Pennsylvania accession Ames 3103, aa) and novel (Netherlands accession PI 641691, bb) genotypes, the F2 population (n = 104) leaf and root tissues were extracted, analyzed for Hy and Sc contents, and compared with the h6h genotypes (aa, ab, bb). The polymorphism showed Mendelian inheritance. The presence of the polymorphic gene bb showed a marginally significantly greater concentration of hyoscyamine in the leaf tissue (P = 0.0675) and significantly greater concentration in root tissue (P = 0.0436), along with increased concentration of scopolamine in the root tissue (P = 0.0494) compared with the aa genotype. The increase in overall TA in the root tissue of the genotype bb was accompanied by a reduction in scopolamine in the foliar tissue. The 694-bp b amplicon has been sequenced for comparison with the expected 550-bp a amplicon and can be a useful enzymatic variant for TA metabolic engineering.

Recent data showing fast degradation of the emerging disinfection by-product 2,6-dichloro-1,4-benzoquinone (DCBQ) in the presence of free chlorine seem incompatible with the high concentrations reported in drinking water distribution systems. The current study was conducted to reconcile this apparent incompatibility. Laboratory tests showed that the published protocol for DCBQ preservation, addition of formic acid without conventional reducing agents, was problematic. Formic acid does not rapidly reduce free chlorine, allowing chlorine residuals to persist during sample workup and analysis. Acidic conditions from formic acid addition along with a persistent free chlorine residual catalyzed additional DCBQ formation when organic precursors were present. This led to large positive analytical bias during formation potential testing using raw water and model precursors. DCBQ levels previously reported using the formic acid preservation method are likely to show a strong positive bias. For future testing, we recommend the use of glycine or arsenite followed by formic acid.

Traditional approaches toward evaluating oil spill mitigation effectiveness in drinking water supplies using analytical chemistry can overlook residual hydrocarbons and treatment byproducts of unknown toxicity. Zebrafish (Danio rerio) were used to address this limitation by evaluating the reduction in toxicity to fish exposed to laboratory solutions of dissolved crude oil constituents treated with 3 mg/L ozone (O3 ) with or without a peroxone-based advanced oxidation process using 0.5 M H2 O2 /M O3 or 1 M H2 O2 /M O3 . Crude oil water mixtures (OWMs) were generated using three mixing protocols-orbital (OWM-Orb), rapid (OWM-Rap), and impeller (OWM-Imp) and contained dissolved total aromatic concentrations of 106-1019 µg/L. In a first experiment, embryos were exposed at 24 h post fertilization (hpf) to OWM-Orb or OWM-Rap diluted to 25%-50% of full-strength samples and in a second experiment, to untreated or treated OWM-Imp mixtures at 50% dilutions. Toxicity profiles included body length, pericardial area, and swim bladder inflation, and these varied depending on the OWM preparation, with OWM-Rap resulting in the most toxicity, followed by OWM-Imp and then OWM-Orb. Zebrafish exposed to a 50% dilution of OWM-Imp resulted in 6% shorter body length, 83% increased pericardial area, and no swim bladder inflation, but exposure to a 50% dilution of OWM-Imp treated with O3 alone or with 0.5 M H2 O2 /M O3 resulted in normal zebrafish development and average total aromatic destruction of 54%-57%. Additional aromatic removal occurred with O3  + 1 M H2 O2 /M O3 but without further attenuation of toxicity to zebrafish. This study demonstrates using zebrafish as an additional evaluation component for modeling the effectiveness of freshwater oil spill treatment methods. Environ Toxicol Chem 2022;41:2822-2834. © 2022 SETAC.

Urine contains high concentrations of nitrogen and phosphorus, which can be utilized as fertilizer in sustainable agriculture, forestry, and landscaping. Before urine application, the nitrogen can be stabilized with calcium hydroxide (lime), which raises the pH and inhibits urea hydrolysis. However, the impact of lime-treated urine on plants and soils remains unclear. Here, lime-treated urine diluted 1:10 with water was applied to soils with sunflowers (Helianthus annuus L.), and growth and soil bacterial diversity was examined at 2 months. We show that lime-treated urine significantly increased sunflower growth up to 85 %, plant biomass up to 151 %, leaf area up to 137 %, and the number of leaves per plant by 2.5 compared to untreated plants. No major differences in bacterial Shannon or Simpson diversity indices were detected between treatment groups, though small shifts in phyla composition were observed, depending on treatment and plant presence. This work demonstrates that recycled urine can effectively be used for the fertilization of non-food crops and landscaping plants.

Iodinated disinfection by-products (I-DBPs) have recently emerged as part of the pool of DBPs of public health concern. Due to limitations in measuring individual I-DBPs in a water sample, the surrogate measure of total organic iodine (TOI) is often used to account for the sum of all I-DBPs. In this study, TOI and total iodine (TI) are quantified in raw and treated waters in treatment trains at three sites in the Northeast United States. The occurrence, magnitude, and seasonality of these species was investigated within each sampling train and across the different sites. A regression model was developed to explore how TOI occurrence varies with routinely measured physical and chemical parameters in a water sample. The TOI and TI concentration at the three sites ranged from below the method detection limit to 18 mu g/L and from 3 and 18.9 mu g/L, respectively. There was substantial inter-monthly variability in TOI without a clear seasonal signal, and the concentration of TOI did not increase upon treatment. The results of the multivariate regression model showed that dissolved organic carbon (DOC), specific UV254 absorbance (SUVA), combined chlorine residual (TCl2), and pH were all significantly related to TOI concentration to varying degrees. A Tobit model was fit to show TOI predictions against observed (measured) TOI values. The model could explain approximately 46% of the variance of TOI concentrations in the treated waters. (c) 2020 Elsevier Ltd. All rights reserved.

Halobenzoquinones (HBQs) are emerging disinfection by-products (DBPs) that are postulated drivers of bladder carcinogenicity. Prior assessments of 2,6-dichloro-1,4-benzoquinone (DCBQ) occurrence in drinking water distribution systems have revealed a gradual decline with increasing distance from points of entry. While this signals a degradation pathway, there is limited quantitative data on rate of that degradation. A systematic evaluation of DCBQ hydrolysis was performed, resulting in a rate law that is first order in both hydroxide [OH-] and [DCBQ]. The impact of temperature on that rate was characterized according to the Arrhenius relationship. Under the conditions tested (pH similar to 7.2, T = 20 degrees C) chloramine did not significantly impact DCBQ concentrations. However, DCBQ was rapidly degraded in solutions containing free available chlorine (FAC). Kinetic analysis showed non-integer order with respect to FAC. Further investigation led to a model that invoked reaction with dichlorine monoxide (Cl2O) as well as FAC. (C) 2021 Elsevier Ltd. All rights reserved.