Full-scale multisampling and empirical modeling of DBPs in water and air of indoor pools.

Disinfection by-products (DBPs) are formed in the water in swimming pools due to reactions between disinfectants (chlorine, bromine, ozone) and the organic matter introduced by bathers and supply water. High concentrations of DBPs are also reported in the air of indoor swimming pools. Based on a robust multisampling program, the levels and variations of DBPs in the air (trichloramine [TCAM] and trihalomethanes [THMs]) and water (THM) were assessed, as well as their precursors (total organic carbon, water temperature, pH, free, and total chlorine) and proxies (CO2 and relative humidity) in four indoor chlorinated swimming pools. High-frequency sampling was conducted during one high-attendance day for each pool. This study focused on parameters that are easy to measure in order to develop models for predicting levels of THMs and TCAM in the air. The results showed that the number of bathers had an important impact on the levels of THMs and TCAM, with a two-to-three-fold increase in air chloroform (up to 110 µg/m3) and a two-to-four-fold increase in TCAM (up to 0.52 mg/m3) shortly after pools opened. The results of this study for the first time showed that CO2 and relative humidity can serve as proxies for monitoring variations in airborne THMs and TCAM. Our results highlight the good predictive capacity of the developed models and their potential for use in day-to-day monitoring. This could help optimize and control DBPs formation in the air of indoor swimming pools and reduce contaminant exposure for both pool employees and users.

Temporal and spatial variations in the levels of prominent airborne disinfection by-products at four indoor swimming pools.

Exposure to airborne disinfection by-products, especially trichloramine and trichloromethane, may cause various adverse health effects for the workers and users of indoor swimming pools. This study aims to evaluate the spatial and temporal variations in trichloramine and trichloromethane concentrations within and between swimming pools. Workplace measurements were carried out at four indoor swimming pools in Quebec (Canada) during the cold season. To fully represent daily operating conditions, sampling started 2 hr before the swimming pool opened and continued until 2 hr after closing. To quantify trichloramine and trichloromethane concentrations, 304 air samples have been collected. Temperature, humidity, and CO2 were measured-simultaneously every 2 hr. The results showed that both trichloramine and trichloromethane concentrations varied significantly in time. The observed daily variations in trichloramine and trichloromethane concentrations suggest that the common practice of collecting a single 2-hr air sample does not represent daily pool trichloramine and trichloromethane contamination levels and, consequently, does not represent the true exposure and health risks for workers that are present for a full 8-hr shift. This study recommends a new 8-hr sampling strategy or a full-shift strategy using a cassette with three impregnated filters as a valid and cost-effective solution for comparing time-weighted average (TWA) concentrations to permissible trichloramine exposure limits.

L'évaluation d'impact sur la santé, un outil pour promouvoir des politiques climatiques favorables à la santé.

INTRODUCTION: Potential impacts of climate change on health are increasingly studied due to the diversity of the associated risks (heatwaves, air pollution, water- and vector-borne diseases). Consequently, adaptation and mitigation strategies, including tools, have been developed by different cities, states, and organizations to assess the effects of climate change on health. OBJECTIVE: Health impact assessment (HIA) is a tool that could be used to assess the potential health impacts of climate change policies before their implementation. The objective of this study is therefore to analyze the way HIA is used in the development of these policies. METHOD: A scoping review of grey and scientific literature in French and English (period: 1990-2019) allowed us to identify 35 articles and reports, with 6 using HIA specifically. The areas of HIA application related to transport, urban planning or the building sector. The main health issues addressed in these HIAs concerned air, noise, physical activity, urban heat islands, green spaces, and functional diversity. RESULTS: These studies have shown that HIA is an approach that can facilitate cross-sectoral collaboration, and its flexibility allows for its application to adaptation and mitigation policies, as well as at several spatial scales (cities, regions). DISCUSSION: The principal limitation in this approach relates to uncertainties associated with quantifying projected impacts.

A methodology to prioritize spatio-temporal monitoring of drinking water quality considering population vulnerability.

The optimization of drinking water monitoring becomes increasingly complex with the size of a water distribution system. Municipal water managers have to combine their experiences with different types of information (historical water quality variability, infrastructure, water residence times, sociodemographic profiles, etc.) that are available in different forms (qualitative, quantitative, geographical, etc.) to be able to select the monitoring locations for regulatory compliance and routine water quality management and control. Therefore, the integration of such information requires to select suitable variables and use the appropriate data mining and aggregation methods. This work aims to develop a methodology that helps optimize drinking water quality monitoring programs by considering the different components of population vulnerability that vary both spatially and temporally. This project was conducted in a distribution system that supplies approximately 510 000 citizens. Due to the high seasonal climatic variations and the size of the network, there are also considerable spatial and temporal variations in water quality throughout the year. An index representing the spatio-temporal population vulnerability (combination of population exposure, sensitivity and adaptation capacity) to the degradation of drinking water quality was developed by selecting the relevant parameters and aggregation methods. The population vulnerability index was calculated by aggregating spatio-temporal water quality data (representing microbiological and chemical risks) and distribution network characteristics (number of leakages, pipes type and age). This information was then compared with sociodemographic data related to population sensitivity (percentage of children and the elderly, and the number of health care centers) and the population's adaptive capacity (social and material deprivation). A fuzzy synthetic evaluation method is used for parameter aggregation and to calculate the different indexes. By considering variable locations and periods of time that may better represent the population vulnerability, the results of this project are useful for drinking water managers to optimize their drinking water monitoring strategies.

Development of a drinking water quality index based on a participatory procedure using mixed multicriteria methods.

The objective of this study is to propose and apply a novel approach to develop a drinking water quality index that enables water managers to routinely identify the vulnerabilities in a distribution system (DS) while taking into account the priorities of water managers and operators. Here, we propose an innovative approach based on the participation of eight researchers and water managers. The input from these participants was included through a combination of the Delphi and MACBETH (Measuring Attractiveness by a Categorical-Based Evaluation Technique) methods, which were applied to an index developed using fuzzy logic. The index was then validated by conducting sensitivity and comparative analyses on a database from field sampling campaigns conducted in various small municipal DSs in two Canadian provinces: Quebec and Newfoundland and Labrador. Finally, the drinking water quality index was applied to a database of the DS in Quebec City, Canada. Sensitivity and comparative analyses revealed that the developed index could allow for the characterization of water sample quality and could prove useful for prioritizing interventions in the DS. The index was also useful for representing the spatial variability of water quality, and provided nuanced information about water quality, especially when the water quality parameter values complied with guidelines and regulations. These results provide a transferable and integrated approach for developing customized drinking water quality indices. This study will help pave the way for water quality managers to better prevent episodes of possible water quality deterioration.

Heavy Rainfall Impacts on Trihalomethane Formation in Contrasting Northwestern European Potable Waters.

There is emerging concern over the impact of extreme events such as heavy rainfall on the quality of water entering the drinking water supply from aboveground sources, as such events are expected to increase in magnitude and frequency in response to climate change. We compared the impact of rainfall events on streamwater quality in four contrasting upland (peatland and mineral soil) and lowland agricultural catchments used to supply drinking water in France (Brittany) and the United Kingdom (North Wales) by analyzing water samples collected before, during, and after specific events. At all four streams, heavy rainfall led to a considerable rise in organic matter concentration ranging from 48 to 158%. Dissolved organic carbon (DOC) quality, as determined using specific ultraviolet absorbance, changed consistently at all sites during rainfall events, with a greater proportion of aromatic and higher molecular weight compounds following the onset of rainfall. However, the change in DOC quality and quantity did not significantly alter the trihalomethane formation potential. We observed small increases in trihalomethane (THM) generation only at the Welsh peatland and agricultural sites and a small decrease at the Brittany agricultural site. The proportion of brominated THMs in chlorinated waters was positively correlated with bromide/DOC ratio in raw waters for all sites and hydrological conditions. These results provide a first indication of the potential implications for surface-based drinking water resources resulting from expected future increases in rainfall event intensity and extension of dry periods with climate changes.

Assessment of rain event effects on source water quality degradation and subsequent water treatment operations.

Heavy rainfall events can lead to the runoff of large amounts of dissolved and particulate matter into surface water sources that may represents challenges for drinking water treatment, such as membrane fouling, increases in chemical demands, and formation of various disinfection by products (DBPs) after disinfection, such as trihalomethanes (THM) and haloacetic acids (HAA). In this study, a framework is defined for analyzing water quality data in relation to climatic variables (rainfalls). The effects of 22 different rain events were assessed on an organic matter proxy (UV absorbance), and on different key water quality parameters for the coagulation step in a drinking water treatment plant. Extended impacts of rewetting events after long term dry period on source water quality were identified, with significant increases in raw water UV 254 nm that last almost 3 weeks. A significant effect on filtered water quality was also noticed and the potential impacts on finished waters quality was confirmed by HAA modelling results. Future studies could focus on the monitoring and modelling of other regulated DBPs such as THM as well as simulations of different scenarios of climate change to estimate the variability of DBPs and its precursors such as organic matter.

Tools and Methods to Include Health in Climate Change Adaptation and Mitigation Strategies and Policies: A Scoping Review.

Climate change represents a serious threat to the health and well-being of populations. Today, many countries, regions, and cities around the world are implementing policies and strategies to adapt to climate change and mitigate its effects. A scoping review was performed to identify tools and methods that help integrate health into climate change adaptation and mitigation policies and strategies. The literature search includes scientific and grey literature. The scientific literature was conducted using PubMed, Elsevier Embase, and Web of Science databases. A grey literature web search was performed to complement the results. A total of 35 studies (28 from the scientific literature and 7 from the grey literature) were finally included. A large majority of research articles (24/28) and almost all reports (6/7) from the grey literature were published after 2010. Results show that the tools that were found most frequently are the nested models (12/35), health impact assessment (6/35), vulnerability and adaptation assessment (3/35), conceptual frameworks (3/35), and mixed methods (3/35). This review shows an increasing interest in the topic of developing tools to better manage health issues in adaptation and mitigation strategies, with a recent increase in the number of publications. Additional analyses of tools' effectiveness should be conducted in further studies.

Perception of tap water quality: Assessment of the factors modifying the links between satisfaction and water consumption behavior.

Perception of tap water is subject to a wide range of factors and interactions. These include risk perception, tap water quality and organoleptic perceptions, microbiological and chemical quality, prior experiences, information sources, trust in water companies and other groups, and perceived control and contextual factors, among others. The objective of this study is to assess the factors that influence and determine citizen behavior regarding drinking water. A phone survey was conducted among 1014 citizens living in the city of Québec, Canada. Five different domestic water consumption profiles were elaborated according to the citizens' preferences and behavior. Descriptive statistics and mediation analyses were carried out to analyse the survey results and assess the factors modifying the links between satisfaction and water consumption behavior. Results show that drinking water quality could be loosely linked with overall satisfaction with tap water. The water consumption profile was strongly linked with satisfaction levels related to the taste, odor and color of tap water. We observed that the association between an individual's tap water satisfaction and water consumption behavior was mediated by the water treatment strategies applied at home (filtering, cooling), knowledge about drinking water quality and its production, and risk perception. The mediating effects were shown to be significant mainly among bottled-water-only and tap-water-only consumers. Future interventions that aim to encourage the population's use of tap water as a primary source should prioritize cooling and filtering tap water in their messaging, in order to improve population satisfaction. The reduction of risk perception through targeted information campaigns is also of primary importance for decreasing the number of citizens who exclusively drink bottled water.

Optimizing disinfection by-product monitoring points in a distribution system using cluster analysis.

Trihalomethanes (THMs) and Haloacetic Acids (HAAs) are the main groups detected in drinking water and are consequently strictly regulated. However, the increasing quantity of data for disinfection byproducts (DBPs) produced from research projects and regulatory programs remains largely unexploited, despite a great potential for its use in optimizing drinking water quality monitoring to meet specific objectives. In this work, we developed a procedure to optimize locations and periods for DBPs monitoring based on a set of monitoring scenarios using the cluster analysis technique. The optimization procedure used a robust set of spatio-temporal monitoring results on DBPs (THMs and HAAs) generated from intensive sampling campaigns conducted in a residential sector of a water distribution system. Results shows that cluster analysis allows for the classification of water quality in different groups of THMs and HAAs according to their similarities, and the identification of locations presenting water quality concerns. By using cluster analysis with different monitoring objectives, this work provides a set of monitoring solutions and a comparison between various monitoring scenarios for decision-making purposes. Finally, it was demonstrated that the data from intensive monitoring of free chlorine residual and water temperature as DBP proxy parameters, when processed using cluster analysis, could also help identify the optimal sampling points and periods for regulatory THMs and HAAs monitoring.

Heterogeneity in the Relationship between Disinfection By-Products in Drinking Water and Cancer: A Systematic Review.

The epidemiological evidence demonstrating the effect of disinfection by-products (DBPs) from drinking water on colon and rectal cancers is well documented. However, no systematic assessment has been conducted to assess the potential effect measure modification (EMM) in the relationship between DBPs and cancer. The objective of this paper is to conduct a systematic literature review to determine the extent to which EMM has been assessed in the relationship between DBPs in drinking water in past epidemiological studies. Selected articles (n = 19) were reviewed, and effect estimates and covariates that could have been used in an EMM assessment were gathered. Approximately half of the studies assess EMM (n = 10), but the majority of studies only estimate it relative to sex subgroups (n = 6 for bladder cancer and n = 2 both for rectal and colon cancers). Although EMM is rarely assessed, several variables that could have a potential modification effect are routinely collected in these studies, such as socioeconomic status or age. The role of environmental exposures through drinking water can play an important role and contribute to cancer disparities. We encourage a systematic use of subgroup analysis to understand which populations or territories are more vulnerable to the health impacts of DBPs.

Variability of disinfection by-products at a full-scale treatment plant following rainfall events.

The quality of drinking water sources can decrease when contaminants are transported by overland and subsurface flow and discharged into surface waters following rainfall events. Increases in organic contaminants such as road salts and organic matter may occur and potentially modify disinfection by-products (DBPs) concentration and speciation. This study investigated the effects of various spring rainfall events on the quality of treated waters at a large water treatment plant through the implementation of intensive water quality monitoring of raw, filtered and treated waters during different rainfall events. DBPs (four trihalomethanes and six haloacetic acids) and their explanatory variables (pH, turbidity, water temperature, specific ultraviolet absorbance, total and dissolved organic carbon, bromide and chlorine dose) were measured during four rainfall events. The results showed that water quality degrades during and following rainfall, leading to small increases in trihalomethanes (THM4) and haloacetic acids (HAA6) in treated waters. While THM4 and HAA6 levels remained low during the pre-rainfall period (<9 µg/L) for the four sampling campaigns, small increases in THM4 and HAA6 during and after spring rainfall events were observed. During the rainfall and post-rainfall periods, concentration peaks corresponding to 3-fold and 2-fold increases (respectively 27.5 µg/L for THM4 and 12.6 µg/L for HAA6) compared to pre-rainfall levels were also measured. A slight decrease in harmful brominated THM and HAA proportion was also observed following rainfall events.

Experimental disinfection by-product formation potential following rainfall events.

Spring rainfall events can have deleterious impacts on raw and drinking water quality for water treatment plants that use surface waters. This study compares the influence of land use and climate on DBP precursors in two catchments supplying the region around the City of Québec, Canada, and assesses the variability of Disinfection By-Product (DBP) concentration and speciation following rainfall events. DBPs (trihalomethanes (THMs) and haloacetic acids (HAAs)) and their precursors in raw waters (pH, turbidity, specific ultraviolet absorbance (SUVA), total and dissolved organic carbon, bromides and chlorine dose) were monitored. Various experimental chlorination tests, DBP formation potential (DBPFP) and Simulated Distribution Systems (SDS), were also performed. Differences in pre-rainfall (baseflow) water quality were noted according to the different watershed land uses. Raw water quality patterns showed modifications between baseflow and rainfall periods, with a degradation of raw water quality according to turbidity and SUVA in both water sources. Rainfall events were also shown to alter organic matter reactivity with an increase in THM formation potential for both sites. A less noticeable impact on HAA formation potential was observed. However, no clear differences in DBPFP tests were observed between the sites. SDS tests showed that rainfall events lead to considerable rises in organic carbon reactivity of filtered waters, even after primary treatment, with a 2-fold increase in THM and HAA concentrations following rainfall for waters representing the end of one main distribution system (20 h contact time). These increases are linked mainly to a rise in non-brominated DBPs such as chloroform, trichloroacetic acid and dichloroacetic acid. This study confirms the importance of strictly controlling OM levels during drinking water treatment to ensure safe drinking water quality throughout the distribution system.

Investigating social inequalities in exposure to drinking water contaminants in rural areas.

Few studies have assessed social inequalities in exposure to drinking water contaminants. This study explores this issue in 593 rural municipalities of Québec, Canada. Quartiles of an ecological composite deprivation index were used as a proxy of socioeconomic status. Total trihalomethanes (TTHMs) and lead were chosen as proxies of chemical drinking water quality. The results show that the majority of deprived rural municipalities apply no treatment to their water (26%) or use a basic treatment (51%), whereas a relative majority of the wealthiest municipalities (40%) use advanced treatment. The proportion of municipalities having important lead (>5 µg/L) levels is highest in most deprived municipalities. Moreover, most deprived municipalities have a higher risk of high tap lead levels (RR = 1.33; 95%CI: 1.30, 1.36). Conversely, most deprived municipalities have a lower risk of high TTHMs levels (RR = 0.78; 95%CI: 0.69, 0.86). These findings suggest an environmental inequality in drinking water contaminants distribution in rural municipalities.

Effects of future climate and land use scenarios on riverine source water quality.

Surface water quality is particularly sensitive to land use practices and climatic events that affect its catchment. The relative influence of a set of watershed characteristics (climate, land use, morphology and pedology) and climatic variables on two key water quality parameters (turbidity and fecal coliforms (FC)) was examined in 24 eastern Canadian catchments at various spatial scales (1 km, 5 km, 10 km and the entire catchment). A regression analysis revealed that the entire catchment was a better predictor of water quality. Based on this information, linear mixed effect models for predicting turbidity and FC levels were developed. A set of land use and climate scenarios was considered and applied within the water quality models. Four land use scenarios (no change, same rate of variation, optimistic and pessimistic) and three climate change scenarios (B1, A1B and A2) were tested and variations for the near future (2025) were assessed and compared to the reference period (2000). Climate change impacts on water quality remained low annually for this time horizon (turbidity: +1.5%, FC: +1.6%, A2 scenario). On the other hand, the influence of land use changes appeared to predominate. Significant benefits for both parameters could be expected following the optimistic scenario (turbidity: -16.4%, FC: -6.3%; p < 0.05). However, pessimistic land use scenario led to significant increases on an annual basis (turbidity: +11.6%, FC: +15.2%; p < 0.05). Additional simulations conducted for the late 21st century (2090) revealed that climate change impacts could become equivalent to those modeled for land use for this horizon.

A decision support system for drinking water production integrating health risks assessment.

The issue of drinking water quality compliance in small and medium scale water services is of paramount importance in relation to the 98/83/CE European Drinking Water Directive (DWD). Additionally, concerns are being expressed over the implementation of the DWD with respect to possible impacts on water quality from forecast changes in European climate with global warming and further anticipated reductions in north European acid emissions. Consequently, we have developed a decision support system (DSS) named ARTEM-WQ (AwaReness Tool for the Evaluation and Mitigation of drinking Water Quality issues resulting from environmental changes) to support decision making by small and medium plant operators and other water stakeholders. ARTEM-WQ is based on a sequential risk analysis approach that includes consideration of catchment characteristics, climatic conditions and treatment operations. It provides a holistic evaluation of the water system, while also assessing human health risks of organic contaminants potentially present in treated waters (steroids, pharmaceuticals, pesticides, bisphenol-a, polychlorobiphenyls, polycyclic aromatic hydrocarbons, petrochemical hydrocarbons and disinfection by-products; n = 109). Moreover, the system provides recommendations for improvement while supporting decision making in its widest context. The tool has been tested on various European catchments and shows a promising potential to inform water managers of risks and appropriate mitigative actions. Further improvements should include toxicological knowledge advancement, environmental background pollutant concentrations and the assessment of the impact of distribution systems on water quality variation.

Impacts of rainfall events on runoff water quality in an agricultural environment in temperate areas.

Since a rise in dissolved organic carbon (DOC) concentrations has been observed for surface waters at least over the last two decades, a change in weather conditions (temperature and precipitations) has been proposed to partly explain this increase. While the majority of DOC delivery from soils to stream occurs during rainfall events, a better understanding of the rainfall influence on DOC release is needed. This study has been conducted in Brittany, western France, on agricultural experimental plots receiving either cattle manure (CM) or pig slurry (PS) as fertilizers in accordance with local practices. Each plot was instrumented with a flow meter and an auto sampler for runoff measurements. The results show that export of DOC during high intensity events is higher than during lower intensity rainfalls. Fertilization has a noticeable impact on total organic carbon (TOC) fluxes with an increase of five to seven folds for PS and CM respectively. If TOC shock load occurs shortly after the rainfall peak, DOC maximum appears with the first flush of the event. Organic carbon (OC) is mainly under colloidal (41.2%) and soluble (23.9%) forms during the first stage of a rainfall event and a control of rainfall intensity on OC colloidal transport is suggested. These findings highlight the potential risk of receiving water quality degradation due to the increase of heavier rainfall events with climate change in temperate areas.