Ontario Drinking Water Research Articles

Drinking water quality management progress in Ontario, two decades after Walkerton.

Following the waterborne disease outbreak in Walkerton, Ontario, the province made significant efforts to implement recommendations of the public inquiry that resulted. As Ontario reformed its drinking water sector, other jurisdictions were advancing risk-based quality management frameworks for drinking water, including the World Health Organization (WHO) through its water safety plan (WSP) framework. Two decades after the Walkerton tragedy, this paper seeks to: (i) evaluate alignment of Ontario's Drinking Water Quality Management Standard (DWQMS) with the WSP framework (ii) review readily available data for evidence that Ontario's DWQMS implementation has improved drinking water safety and promoted a preventive approach through risk-based quality management. Our study found strong alignment between the Ontario DWQMS and WSP frameworks, with supporting programmes and risk assessment procedures present. Analysis of available regulatory data revealed abundant reporting of water quality and adverse incidents in municipal water systems. However, performance data were publicly available, the use of percentage scores for water quality testing obscures the details of system performance and water safety. Reports describing the DWQMS plan and audit results were difficult to obtain and not standardized. There is a need to develop mechanisms to ensure continual improvement of the DWQMS.

Portable Rapid Paper-Based Device for Analysis of Carbamates and Organophosphates in Water Samples

Traditionally, the analysis of contaminants in water samples is performed using sophisticated techniques, namely HPLC, GC, and MS, requiring qualified personnel and laboratory infrastructure. Such methods are not feasible for the detection of contaminants in the field. In contrast, paper-based portable devices have been demonstrated as versatile, sustainable, and cheap solutions for such purposes. Paper consists of a pressed sheet of entangled hydrophilic cellulose fibres with excellent porosity. Such features enable the capillarity motion of liquids and the immobilization of active substances on the surface.Pesticides are critical pollutants in regions where agricultural activity is intense and represent a serious health risk for rural workers and their communities. These chemicals have been applied in enormous quantities to increase crop production in many countries. Carbamates (CBs) and organophosphates (OPs) are employed as active ingredients in industrial formulations of insecticides. They are considered highly toxic due to their inhibition action in the cholinergic transmission found in the nervous system of living organisms.This work aims to present a low-cost and simple operational paper-based testing device for the fast detection of CBs and OPs in water samples based on Ellman’s method of acetylcholinesterase (AChE) inhibition. We have named the proposed device “dip-and-fold” due to its how-to-use procedure: first, the device’s bottom edge is dipped in the water sample. The liquid moves up by capillarity towards the detection zone, in which the analytes find the AChE previously immobilized on the paper. The top edge of the paper is covered with a thin parafilm layer to avoid leaking.After a 10-minute incubation, the AChE is inhibited in the presence of CBs and/or OPs. Then, the device is folded to release both enzymatic substrate acetylthiocholine iodide (ACThI) and indicator 5,5′-Dithiobis (2-nitrobenzoic acid) (DTNB) from a secondary paper to the detection zone for the colorimetric reaction. The detection zone area remains white in the presence of CBs and/or OPs (inhibited AChE); otherwise, it becomes yellow in the absence of these pesticides (active AChE).It is worthy to emphasize that the dip-and-fold has all required ingredients immobilized onto the paper substrates prior to tests, which excludes the necessity of extra reagents and materials. Besides, the sample can be transferred to the device by capillarity motion when dipping it directly into the contaminated water, eliminating any risk of having contact with the pesticides. Experiment The dip-and-fold device was fabricated using two analytical papers and a backing card as a foldable scaffold. Blotting paper (Whatman GB003) was used as the main device’s component for the sample loading by capillarity as well as for the immobilization of 3 µL AChE (100 U/mL), using chitosan 1% (w/v, in acetic acid 2%), as a crosslinker. The secondary component was the filter paper (Whatman grade 4) in which the 3µL of the substrate ACThI (25mM) and 3 µL of DTNB (10mM) were impregnated on the surface. The detection tests were carried out using standard solutions of carbofuran, propoxur (both carbamates) and chlorpyriphos (an organophosphate) at concentrations between 0.1 and 0.0001 mM. Control samples of DI water were also tested. A minimum volume of methanol was required to dissolve the pesticides in water. Yellow-coloured results of the tests were evaluated by taking digital photos of the devices using a smartphone. The RGB channels of images were analyzed using ImageJ software. Results and Conclusion The result interpretation was performed by comparing the plotted curves of the blue channel (B) values obtained from the images of each tested device for the different analytes and their respective concentrations. The evaluation of the plotted curves confirmed that the yellow colour's intensity is inversely proportional to the concentration of the analytes in the sample, which means, the more intense the yellow, the lower the concentration of pesticides in the sample. The concentrations applied in this study meet the parameters proposed by the Ontario Drinking Water Quality Standards (ODWQS) and may be compared to other paper-based devices described in the literature.Both propoxur and carbofuran presented consistent results that were observed by a steady decrease of the B values related to their concentration. In contrast, the chlorpyrifos presented a non-linear curve, which can be attributed to the higher amount of methanol used as a co-solvent to dissolve it in water due to its extremely poor solubility.The dip-and-fold device presented an exclusive, eco-friendly, and economical testing platform for pesticide detection in water, which offers an attractive solution for water assessment in vulnerable areas exposed to these toxic chemicals. Figure 1

Phylogenies of microcystin-producing cyanobacteria in the lower Laurentian Great Lakes suggest extensive genetic connectivity.

Lake St. Clair is the smallest lake in the Laurentian Great Lakes system. MODIS satellite imagery suggests that high algal biomass events have occurred annually along the southern shore during late summer. In this study, we evaluated these events and tested the hypothesis that summer bloom material derived from Lake St. Clair may enter Lake Erie via the Detroit River and represent an overlooked source of potentially toxic Microcystis biomass to the western basin of Lake Erie. We conducted a seasonally and spatially resolved study carried out in the summer of 2013. Our goals were to: 1) track the development of the 2013 summer south-east shore bloom 2) conduct a spatial survey to characterize the extent of toxicity, taxonomic diversity of the total phytoplankton population and the phylogenetic diversity of potential MC-producing cyanobacteria (Microcystis, Planktothrix and Anabaena) during a high biomass event, and 3) compare the strains of potential MC-producers in Lake St. Clair with strains from Lake Erie and Lake Ontario. Our results demonstrated a clear predominance of cyanobacteria during a late August bloom event, primarily dominated by Microcystis, which we traced along the Lake St. Clair coastline downstream to the Detroit River's outflow at Lake Erie. Microcystin levels exceeded the Province of Ontario Drinking Water Quality Standard (1.5 µg L−1) for safe drinking water at most sites, reaching up to five times this level in some areas. Microcystis was the predominant microcystin producer, and all toxic Microcystis strains found in Lake St. Clair were genetically similar to toxic Microcystis strains found in lakes Erie and Ontario. These findings suggest extensive genetic connectivity among the three systems.

Nationwide assessment of nitrosamine occurrence and trends

Nitrosamine data reported from the first rounds of samples collected under the second Unregulated Contaminants Monitoring Rule (UCMR2) and the Ontario Drinking Water Surveillance Program were reviewed to assess the frequency and magnitude of occurrence and the effect of disinfectant type and other treatment factors on reported nitrosamine concentrations. Initial monitoring data reveal that N‐nitrosodimethylamine (NDMA) was detected in drinking water at concentrations higher than the UCMR2 minimum reporting level (MRL) of 2 ng/L in 1 of every 10 samples. Other nitrosamines (e.g., N‐nitrosodiethylamine, N‐nitroso‐di‐n‐butylamine, N‐nitrosopyrrolidine, and N‐nitroso‐methylethylamine) were rarely detected at levels above their MRLs. NDMA was primarily detected in systems using chloramines, with more than two thirds of all chloraminated water systems detecting NDMA in at least one sample. Follow‐up survey results from 45 water systems participating in UCMR2 and 6 water systems from Ontario, Canada, generally followed expected trends based on the literature. NDMA occurrence was more frequent and concentrations were higher in water systems having long contact times with chloramines. A comparison of maximum‐residence‐time distribution system samples with entry point samples indicates that NDMA concentrations may increase in a chloraminated distribution system if precursors have not fully reacted at the entry point.

Human Health and the Biological Effects of Tritium in Drinking Water: Prudent Policy Through Science - Addressing the ODWAC New Recommendation.

Tritium is a radioactive form of hydrogen and is a by-product of energy production in Canadian Deuterium Uranium (CANDU) reactors. The release of this radioisotope into the environment is carefully managed at CANDU facilities in order to minimize radiation exposure to the public. However, under some circumstances, small accidental releases to the environment can occur. The radiation doses to humans and non-human biota from these releases are low and orders of magnitude less than doses received from naturally occurring radioisotopes or from manmade activities, such as medical imaging and air travel. There is however a renewed interest in the biological consequences of low dose tritium exposures and a new limit for tritium levels in Ontario drinking water has been proposed. The Ontario Drinking Water Advisory Council (ODWAC) issued a formal report in May 2009 in response to a request by the Minister of the Environment, concluding that the Ontario Drinking Water Quality Standard for tritium should be revised from the current 7,000 Bq/L level to a new, lower 20 Bq/L level. In response to this recommendation, an international scientific symposium was held at McMaster University to address the issues surrounding this change in direction and the validity of a new policy. Scientists, regulators, government officials, and industrial stakeholders were present to discuss the potential health risks associated with low level radiation exposure from tritium. The regulatory, economic, and social implications of the new proposed limit were also considered.The new recommendation assumed a linear-no-threshold model to calculate carcinogenic risk associated with tritium exposure, and considered tritium as a non-threshold chemical carcinogen. Both of these assumptions are highly controversial given that recent research suggests that low dose exposures have thresholds below which there are no observable detrimental effects. Furthermore, mutagenic and carcinogenic risk calculated from tritium exposure at 20 Bq/L would be orders of magnitude less than that from exposure to natural background sources of radiation. The new proposed standard would set the radiation dose limit for drinking water to 0.0003 mSv/year, which is equivalent to approximately three times the dose from naturally occurring tritium in drinking water. This new standard is incongruent with national and international standards for safe levels of radiation exposure, currently set at 1 mSv/year for the general public. Scientific research from leading authorities on the carcinogenic health effects of tritium exposure supports the notion that the current standard of 7,000 Bq/L (annual dose of 0.1 mSv) is a safe standard for human health.Policy-making for the purpose of regulating tritium levels in drinking water is a dynamic multi-stage process that is influenced by more than science alone. Ethics, economics, and public perception also play important roles in policy development; however, these factors sometimes undermine the scientific evidence that should form the basis of informed decision making. Consequently, implementing a new standard without a scientific basis may lead the public to perceive that risks from tritium have been historically underestimated. It was concluded that the new recommendation is not supported by any new scientific insight regarding negative consequences of low dose effects, and may be contrary to new data on the potential benefits of low dose effects. Given the lack of cost versus benefit analysis, this type of dramatic policy change could have detrimental effects to society from an ethical, economical, and public perception perspective.

Factors Influencing Formation of Trihalomethanes in Drinking Water: Results from Multivariate Statistical Investigation of the Ontario Drinking Water Surveillance Program Database

Abstract The presence of trihalomethanes (THMs) in drinking water is an important issue in the context of their potential health effects. Numerous studies have developed models in the past three decades relating THMs concentrations to different factors (e.g., dissolved organic carbon [DOC], chlorine dose, pH, etc.). Previous studies characterized the importance of specific factors through controlled studies using synthetic water or source waters from a small number of water treatment plants. Few studies have reported looking for factors related to THMs formation system-wide across many different water supply systems, and in environments where many factors vary simultaneously. This study presents the results of a multivariate statistical analysis for 162 water supply systems in Ontario, Canada for 2000 to 2004. Principal component analysis (PCA) was applied to determine important factors and possible clusters of variation. PCA identified DOC, chlorine dose, pH, temperature, and reaction time as significant factors for THMs formation. Separate clusters were observed for DOC-colour; chlorine dose-total/free residual chlorine; and hardness-alkalinity. Each cluster indicated factors varying together and representing significant variation. Temperature and pH were found significant and uncorrelated throughout the analysis. The multivariate analysis is the first phase of a continuing investigation into THMs formation with the ultimate goal of developing a predictive model, which can be used to perform human health risk-cost balance studies for drinking water quality management.

The Status of Drinking Water in Ontario, Canada (1992–1999)

This study was conducted to investigate the characteristics of public water works (PWW) in southern Ontario with respect to their water sources and treatment regimes. Data from 481 PWW covering the period 1992-1999 were collected and cartographic manipulations as well as descriptive analyses of the PWW attributes were performed. Tests of associations between different PWW attributes were done using Fisher's Exact test and Cochran-Mantel-Haenszel statistics. Water sources for the PWW included surface water (SW) (21% lakes; 13% rivers), ground water (GW) (64%) and mixed sources (2%). Most (81%) of the population was supplied with SW. Filtration was performed by 84% and 8% of the PWW using SW and GW, respectively. Similarly, disinfection was performed by 99% and 91% of the PWW using SW and GW respectively. There was no significant difference in treatment regimes between PWW in urban and those in rural areas but treatment regime was a function of water source. Overall, most PWW (87.8%) met the minimum treatment requirements of the then Ontario Drinking Water Objectives (ODWO). The study shows that most PWW complied with the minimum treatment requirements of the then ODWO. The minimum treatment required by the ODWO was disinfection for GW and both disinfection and filtration for SW. The non-compliant PWW will need to comply for continued provision of safe drinking water. Suffice it to say that both watershed protection and improved water treatment will be imperative for the continued provision of safe drinking water and control of waterborne diseases.

Drinking water contamination in Walkerton, Ontario: positive resolutions from a tragic event

In May 2000, Escherichia coli O157:H7 and Campylobacter jejuni contaminated the drinking water supply in Walkerton, Ontario. Seven people died and over 2,000 were ill as a result. The Ontario Provincial Government set up a judicial Inquiry into the circumstances surrounding the outbreak and also moved quickly to introduce a new Drinking Water Regulation that incorporated some significant requirements for drinking water providers. The Inquiry itself was in three parts: (a) part 1 related to the events that occurred in Walkerton and why the water contamination occurred; (b) part 1A related specifically to the role of the Provincial Government in the event; and (c) part 2 related to the future of drinking water safety in Ontario with potential to influence regulation on a wider basis. A number of other actions were taken after Walkerton. In August 2000, the Ontario Government, through the Regulatory body, the Ontario Ministry of the Environment (MOE) (a) re-issued and revised the Ontario Drinking Water Objectives (ODWO) as the Ontario Drinking Water Standards (ODWS) and (b) introduced new regulations governing drinking water in Ontario--the Ontario Drinking Water Protection Regulation. One of the key features of the Drinking Water Protection Regulation was the requirement to produce an independent Engineers' Report on all water systems. This paper provides a unique perspective on the Walkerton tragedy and its aftermath. The author was active in many aspects of the resulting activity (Chair of the Ontario Water Works Association's (a section of the AWWA) Special Committee involved in Part 2 of the Walkerton Inquiry; author of several of the Engineers' Reports mandated by Regulation; reviewer on behalf of the Regulator of Engineers' Reports submitted by others). The Engineers' Reports were of interest because (1) the drinking water providers (mostly municipalities) were mandated by regulation to complete the Reports by specific dates and are paying for the Reports, (2) the work had to be done by a registered professional engineer who is not an employee of the owner or the operator if a different entity and (3) the engineer had to sign a declaration that the Regulator could rely on the accuracy of the Report. In other words, the Municipality retained the Engineer and paid them to produce the Report--the Engineer essentially carried the liability while the Regulator had the final say in the acceptability of the Report, a sort of eternal triangle of responsibilities. The paper will outline how the drinking water profession in North America worked together to provide the Walkerton Inquiry with the benefit of its experience and knowledge of best practices to the benefit of consumers and the drinking water providers. It will also outline the procedures adopted to produce the independent Engineers' Reports and how the findings are being applied to further improve drinking water safety in Ontario, across Canada and in similar situations around the world.

Physical Processes Controlling Taste and Odor Episodes in Lake Ontario Drinking Water

Circulation and thermal structure of the coastal waters were studied as a part of an interdisciplinary program to investigate the taste and odor problem in drinking water along the north and western shores of Lake Ontario. The currents and temperature variations were found to be strongly linked to winds, with winds from the west causing upwelling and eastward flowing currents, and winds from the east inducing downwelling and warm westward flowing currents. The downwelling along the north shore during late August and early September of 2000 was associated with a pulse in concentration of the taste and odor causing compound geosmin. This study indicates that during this episode the onshore directed mean currents and cross-shore fluxes in the surface layer transported geosmin to the coastal waters of the north shore.

Disinfection assessment in full-scale chlorine contact chambers

In 1998, the City of Brantford Water Purification Plant was retrofitted with an ultra-high-rate upflow clarification process and two post-clarification chlorine contact chambers. The objective of the work described herein was to assess the theoretical inactivation of Giardia lamblia cysts by free chlorine disinfection in the new chlorine contact chambers. At the time this research was conducted, Ontario drinking water disinfection requirements were not as comprehensive as they are now, following the Walkerton outbreak. In an effort to remain proactive with respect to potential new disinfection regulations in Canada, the 1989 United States Environmental Protection Agency Surface Water Treatment Rule (SWTR) was used to assess the disinfection capability of the City of Brantford chlorine contact chambers. The Ontario Ministry of the Environment promulgated the Ontario Drinking Water Protection Regulation (DWPR) shortly after this project was completed (using the SWTR as a model), reaffirming the relevance of the approach described herein. This study showed that the new chlorine contactors did not provide sufficient contact time to ensure the minimum 0.5-log inactivation of G. lamblia cysts under all potential adverse scenarios. Contactor modifications were made to correct design deficiencies. The comprehensive assessment of the disinfection strategies presented here may be useful to other utilities in Ontario that must now comply with newly implemented DWPRs as well as utilities in other provinces that wish to be proactive with respect to potential new regulations in Canada regarding pathogen control. Key words: surface water treatment rule (SWTR), disinfection, chlorine, Giardia lamblia, CT concept, tracer studies, T10 contact time, log inactivation.

Risky Business: An Analysis of Claimsmaking in the Development of an Ontario Drinking Water Objective for Tritium

Risky Business: An Analysis of Claimsmaking in the Development of an Ontario Drinking Water Objective for Tritium

Risky Business: An Analysis of Claimsmaking in the Development of an Ontario Drinking Water Objective for Tritium

On December 22, 1994, the Minister of Environment and Energy for Ontario announced an interim Ontario Drinking Water Objective for tritium (a radioactive waste product released into drinking water supplies during nuclear power production) of 7,000 Bq/L. The Minister's decision overrode the advice of his own advisory committee which had recommended a much lower level (100 Bq/L). Concerns have surfaced with respect to the potential adverse health effects associated with long-term exposure to low doses of tritium, though much uncertainty remains. This paper explores the struggle over the interpretation of the tritium ‘problem’ as claimsmaking in the context of the social construction of risk. Specifically, the paper documents how coalitions in the dispute constructed and communicated the risks associated with tritium in drinking water through the use of identifiable rhetorical idioms and claimsmaking styles that reflect, reinforce, and legitimize their contrasting core values and interests. The coalitions also adopt fundamentally contrasting risk assessment methods. Using excerpts from public hearings on the issue, the paper explores use of risk as a rhetorical resource through an examination of the contrasting risk assessment paradigms adopted by rival coalitions. Such analysis can contribute to our understanding of the use of scientific information in debates over contentious social problems.

Determination of diquat and paraquat in water by liquid chromatography-(electrospray ionization) mass spectrometry

A method for the determination of the herbicides diquat and paraquat in water was developed using liquid chromatography-(electrospray ionization) mass spectrometry [LC-(ESI)MS]. The analytes were isolated on an ENVI-8 DSK solid phase extraction (SPE) disk and eluted with 5-M trifluoroacetic acid (TFA). The eluate was evaporated to dryness and the analytes were redissolved in the mobile phase (7% methanol/93% water/25-mM TFA). The extract was analyzed by liquid chromatography (C1 column) with postcolumn addition of propionic acid/methanol followed by (ESI)MS. Diquat was detected using the [M 2+ − H +] ion (M 2+ = dication) at m/ z 183, whereas paraquat was detected using the mono-trifluoroacetate ion pair [M 2+/ −OOCCF 3] at m/ z 299. Quantitation was done by isotope dilution mass spectrometry using d 4-diquat and d 8-paraquat and the corresponding ions [M 2+ − D +] and [M 2+/ −OOCCF 3] at m/ z 186 and m/ z 307, respectively. Detection limits of 0.1 and 0.2 μg/L, respectively (based on the dications), were adequate to meet the Ontario Drinking Water Objectives of 70 and 10 μg/L, respectively, and the Ontario Provincial Water Quality Objective for diquat of 0.5 μg/L. Precision and accuracy were 14% and 6% for diquat and 12% and 3% for paraquat.

DETERMINATION OF GROUNDWATER ATTENUATION DISTANCES FOR MUNICIPAL LANDFILL SITES IN ONTARIO

Establishing an attenuation zone is widely used in Ontario to protect groundwater users on property adjacent to the landfill. The main purpose of such an establishment is to provide compliance with the Ministry of Environment and Energy Reasonable Use Policy Objectives (RUPO) at the downgradient attenuation zone boundary. Evaluation of an attenuation zone includes the following: identification of the aquifer to be protected; selection of the list of critical parameters; and the attenuation distance calculations. To select the list of critical contaminants it is recommended to calculate the pollution index (PI), or the ratio between the leachate and RUP concentrations for parameters with established Ontario Drinking Water Objectives. Parameters with the highest values of PI are considered as critical ones and used in attenuation distance calculations. Such calculations are based on the hydrochemistry results at two or more downgradient wells. In particular, a concentration gradient for each critical parame...

A STATISTICALLY BASED TRIGGER MECHANISM FOR EVALUATION OF GROUNDWATER QUALITY IN LANDFILL MONITORING WELLS

According to the Ontario Ministry of Environment and Energy (OMEE) requirement, the owner/operator of a municipal landfill site should develop a detailed contingency plan to deal with unexpected and unacceptable deterioration of groundwater quality at compliance locations. In order to implement such a contingency, a comprehensive trigger mechanism including trigger limits for leachate related parameters, should be in place.The straightforward application of the Reasonable Use Policy Objectives (RUPO) or the Ontario Drinking Water Objectives (ODWO) for defining trigger concentrations can provide a false alarm of unacceptable groundwater contamination at the site boundary due to landfilling operations. In fact, on some occasions, elevated (above the RUPO and ODWO) concentrations at compliance locations could be caused by the variability in groundwater quality rather than the natural man-made activity. In order to avoid this false alarm for contingency implementation, it is proposed to establish trigger limi...