Mixture effects of drinking water disinfection by-products: implications for risk assessment

Stalter, Daniel; O’Malley, Elissa; Gunten, Urs von; Escher, Beate I.

doi:10.1039/c9ew00988d

Cited by 48 publications

(55 citation statements)

References 63 publications

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“…Common detections of contaminants, which often derive from (e.g., Cu, Pb) or are known to change substantially within (e.g., DBP) distribution systems and premise plumbing, reinforce the previously stated (e.g., Bradley et al, 2020 ; Bradley et al, 2018 ; Bradley et al, 2021 ) importance of assessing drinking-water exposures at the point-of-consumption employing an analytical toolbox that more defensibly represents the breadth and complexity of inorganic and organic contaminant mixtures documented to occur in ambient drinking-water sources (e.g., Bradley et al, 2017 ; Moschet et al, 2014 ). The results are consistent with previous TW exposure studies in PR ( Lin et al, 2020 ; Padilla and Vesper, 2018 ; Yu et al, 2015 ), the US ( Bradley et al, 2018 ; Evans et al, 2019 ; Stoiber et al, 2019 ) and elsewhere ( de Jesus Gaffney et al, 2015 ; Gonzalez et al, 2013 ; Leusch et al, 2018 ; Stalter et al, 2020 ; Tröger et al, 2018 ). In line with Safe Drinking Water Information System (SDWIS) violation reporting (accessible online at U.S. Environmental Protection Agency, 2021d ), however, several measured concentrations of DBP with well-documented public-health concerns, including bromodichloromethane and, more broadly, trihalomethanes (THM), were markedly higher than observed in the previous TW studies by this group (e.g., Bradley et al, 2020 ; Bradley et al, 2018 ; Bradley et al, 2021 ) in the mainland US.…”

Section: Resultssupporting

confidence: 92%

Pilot-scale expanded assessment of inorganic and organic tapwater exposures and predicted effects in Puerto Rico, USA

Bradley

Padilla

Romanok

et al. 2021

Science of The Total Environment

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A pilot-scale expanded target assessment of mixtures of inorganic and organic contaminants in point-of-consumption drinking water (tapwater, TW) was conducted in Puerto Rico (PR) to continue to inform TW exposures and corresponding estimations of cumulative human-health risks across the US. In August 2018, a spatial synoptic pilot assessment of than 524 organic and 37 inorganic chemicals was conducted in 14 locations (7 home; 7 commercial) across PR. A follow-up 3-day temporal assessment of TW variability was conducted in December 2018 at two of the synoptic locations (1 home, 1 commercial) and included daily pre- and post-flush samples. Concentrations of regulated and unregulated TW contaminants were used to calculate cumulative in vitro bioactivity ratios and Hazard Indices (HI) based on existing human-health benchmarks. Synoptic results confirmed that human exposures to inorganic and organic contaminant mixtures, which are rarely monitored together in drinking water at the point of consumption, occurred across PR and consisted of elevated concentrations of inorganic contaminants (e.g., lead, copper), disinfection byproducts (DBP), and to a lesser extent per/polyfluoroalkyl substances (PFAS) and phthalates. Exceedances of human-health benchmarks in every synoptic TW sample support further investigation of the potential cumulative risk to vulnerable populations in PR and emphasize the importance of continued broad characterization of drinking-water exposures at the tap with analytical capabilities that better represent the complexity of both inorganic and organic contaminant mixtures known to occur in ambient source waters. Such health-based monitoring data are essential to support public engagement in source water sustainability and treatment and to inform consumer point-of-use treatment decision making in PR and throughout the US.

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Section: Resultssupporting

confidence: 92%

Pilot-scale expanded assessment of inorganic and organic tapwater exposures and predicted effects in Puerto Rico, USA

Bradley

Padilla

Romanok

et al. 2021

Science of The Total Environment

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“…Recent research indicates that ozone oxidizes N -methylamines present in secondary wastewater effluent and generates abundant nitromethane (up to ∼35 μg/L) and that nitromethane is the key intermediate toward halonitromethanes during subsequent chlorination . Halonitromethanes are highly genotoxic − and have been observed in disinfected wastewater and recycled wastewater, particularly in systems using ozone as a primary disinfectant or preoxidant, followed by chlorine or chloramines as a final disinfection step. − In one study on wastewater reuse with ozone/BAC, ozonation was found to increase the halonitromethane formation potential of wastewater by 8–10-fold, but the identity of the halonitromethane precursors remained unknown . The same study found effective removal of halonitromethane precursors by the BAC step after ozonation, but the treatment efficacy of RO and AOP for halonitromethane precursors was not assessed.…”

Section: Introductionmentioning

confidence: 99%

Formation and Fate of Nitromethane in Ozone-Based Water Reuse Processes

Shi

Plata

Kleimans

et al. 2021

Environ. Sci. Technol.

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Ozonation is widely used in wastewater reclamation treatment trains, either for micropollutant control or as a disinfectant and preoxidant in certain reuse processes. We recently found that ozonation of secondary effluent produces nitromethane, which can be efficiently transformed to genotoxic halonitromethanes by chlorination. In this work, the fate of nitromethane through water reuse treatment trains was characterized by analyzing samples from five reuse operations employing ozone. Nitromethane was poorly (<50%) rejected by reserve osmosis (RO), not removed by, and in some cases, increased by ultraviolet/advanced oxidation processes (UV/AOP). Sufficient nitromethane remained after advanced treatment that when chlorine was added to mimic secondary disinfection, halonitromethane formation was consistently observed. In contrast, biological activated carbon removed most (>75%) nitromethane. Bench-scale experiments were conducted to verify low removal by RO in clean systems and with wastewater effluent and to quantify the kinetics of direct and indirect photolysis of nitromethane in UV/AOP. An explanation for increasing nitromethane concentration during AOP is proposed. These results indicate that nitromethane presents a unique hazard to direct potable reuse systems, due to its ubiquitous formation during wastewater ozonation, poor removal by RO and UV/AOP, and facile conversion into genotoxic halonitromethanes upon chlorine addition.

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Section: Disinfection By-products (Dbps)mentioning

confidence: 99%

“…On the other hand, the primary source of disinfection by-products (DBPs) came from the drinking water treatment plant (WTP) [40][41][42]. DBPs were determined in 15 WTPs in Beijing City from various water sources by Stalter et al [40]. They discovered that halogenic acetic acids (HAAs) and trihalomethane (THMs) accounted for 38.1% and 42.6% of all DBPs, respectively, in all treated samples.…”

Section: Disinfection By-products (Dbps)mentioning

confidence: 99%

A Review on Emerging Pollutants in the Water Environment: Existences, Health Effects and Treatment Processes

Arman

Salmiati

Aris

et al. 2021

Water

119

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Emerging pollutants (EPs), also known as micropollutants, have been a major issue for the global population in recent years as a result of the potential threats they bring to the environment and human health. Pharmaceuticals and personal care products (PPCPs), antibiotics, and hormones that are used in great demand for health and cosmetic purposes have rapidly culminated in the emergence of environmental pollutants. EPs impact the environment in a variety of ways. EPs originate from animal or human sources, either directly discharged into waterbodies or slowly leached via soils. As a result, water quality will deteriorate, drinking water sources will be contaminated, and health issues will arise. Since drinking water treatment plants rely on water resources, the prevalence of this contamination in aquatic environments, particularly surface water, is a severe problem. The review looks into several related issues on EPs in water environment, including methods in removing EPs. Despite its benefits and downsides, the EPs treatment processes comprise several approaches such as physico-chemical, biological, and advanced oxidation processes. Nonetheless, one of the membrane-based filtration methods, ultrafiltration, is considered as one of the technologies that promises the best micropollutant removal in water. With interesting properties including a moderate operating manner and great selectivity, this treatment approach is more popular than conventional ones. This study presents a comprehensive summary of EP’s existence in the environment, its toxicological consequences on health, and potential removal and treatment strategies.

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Mixture effects of drinking water disinfection by-products: implications for risk assessment

Abstract: Disinfection by-products (DBPs) in drinking water have been associated with increased cancer risk but effects of known DBPs cannot explain the mixture effects of disinfected water samples.

Cited by 48 publications

References 63 publications

Pilot-scale expanded assessment of inorganic and organic tapwater exposures and predicted effects in Puerto Rico, USA

Pilot-scale expanded assessment of inorganic and organic tapwater exposures and predicted effects in Puerto Rico, USA

Formation and Fate of Nitromethane in Ozone-Based Water Reuse Processes

A Review on Emerging Pollutants in the Water Environment: Existences, Health Effects and Treatment Processes

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