Hi all…as some of you are aware, CTV’s next W5 will focus on asbestos in drinking water. They have, in advance, posted the story online this morning. I have not yet read it.

Health Canada’s website has a ‘guideline-like’ document for asbestos that concluded “Guideline There is no consistent, convincing evidence that ingested asbestos is hazardous. There is, therefore, no need to establish a maximum acceptable concentration (MAC) for asbestos in drinking water.” The WHO, in 2021, also concluded that “it is not considered appropriate or necessary to establish a guideline value for asbestos fibres in drinking-water.”

The USEPA National Primary Drinking Water Regulations currently regulate asbestos with an established a maximum contaminant level (MCL) for asbestos in drinking water of 7 MFL (million fibers per liter > 10 µm in length).

https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations#Inorganic

There will likely be additional information posted on your local AWWA section websites and that of the CWWA.

Bill

Hi all…the USEPA has just proposed MCLs for PFAS compounds. They are requesting comments in much the same way Health Canada does (albeit quite a bit more complicated). Here’s the link to the main website: https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas. Note that there are two associated webinars and there is a lot of supporting information available.

“EPA is proposing a National Primary Drinking Water Regulation (NPDWR) to establish legally enforceable levels, called Maximum Contaminant Levels (MCLs), for six PFAS in drinking water. PFOA and PFOS as individual contaminants, and PFHxS, PFNA, PFBS, and HFPO-DA (commonly referred to as GenX Chemicals) as a PFAS mixture. EPA is also proposing health-based, non-enforceable Maximum Contaminant Level Goals (MCLGs) for these six PFAS.”

Compound	Proposed MCLG	Proposed MCL (enforceable levels)
PFOA	Zero	4.0 parts per trillion (also expressed as ng/L)
PFOS	Zero	4.0 ppt
PFNA	1.0 (unitless) Hazard Index	1.0 (unitless) Hazard Index
PFHxS
PFBS
HFPO-DA (commonly referred to as GenX Chemicals)

Bill

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Per- and Polyfluoroalkyl Substances (PFAS) Proposed PFAS National Primary Drinking Water Regulation

“On March 14, 2023, EPA announced the proposed National Primary Drinking Water Regulation (NPDWR) for six PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS). The proposed PFAS NPDWR does not require any actions until it is finalized. EPA anticipates finalizing the regulation by the end of 2023. EPA expects that if fully implemented, the rule will prevent thousands of deaths and reduce tens of thousands of serious PFAS-attributable illnesses.”

EPA is requesting public comment on the proposed regulation. The public comment period will open following the proposed rule publishing in the Federal Register. Public comments can be provided at that time at www.regulations.gov under Docket ID: EPA-HQ-OW-2022-0114. Information on submitting comments to EPA dockets can be found here.

EPA will be holding two informational webinars about the proposed PFAS NDPWR on March 16, 2023, and March 29, 2023.

Hi all…for those of you interested in PFAS from a Canadian perspective an article entitled “Target and Nontarget Screening of PFAS in Drinking Water for a Large-Scale Survey of Urban and Rural Communities in Québec, Canada” has just appeared in the journal ‘Water Research’. Tap water samples were analyzed for 42 PFAS in 376 municipalities within 17 administrative regions in Quebec and it was found that 99.3% of the tap water samples were positive for at least one PFAS. In addition, “target and nontarget analysis revealed 24 PFAS classes (54 homologs) in tap water.” There is a substantial amount of information that can be gleaned from this screening, for example, comparisons of drinking water produced from groundwater and surface water, discussion of concentrations found vs guidelines/advisories/regulations, impact of pH, methods, etc.

Health Canada’s recently proposed draft objective which is targeting an objective of 30 ng/L for the sum of total per- and polyfluoroalkyl substances (PFAS) in drinking water is mentioned. Note that the Health Canada ‘sum’ refers to the 18 PFAS included in USEPA Methods 533 or 537.1 (vs the 42 surveyed here). Based on this target objective value, the authors report that they found “ten samples from 5 different localities that exceed the proposed 30 ng/L threshold” (using the 18 PFAS).

Bill

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Target and Nontarget Screening of PFAS in Drinking Water for a Large-Scale Survey of Urban and Rural Communities in Québec, Canada

Gabriel Munoz, Min Liu, Sung Vo Duy, Jinxia Liu, Sébastien Sauvé

Water Research Available online 16 February 2023, 119750 In Press, Journal Pre-proof

ABSTRACT

“Limited monitoring data are available regarding the occurrence of emerging per- and polyfluoroalkyl substances (PFAS) in drinking water. Here, we validated an analytical procedure for 42 PFAS with individual detection limits of 0.001-0.082 ng/L. We also evaluated how different sample pH conditions, dechlorinating agents, and storage holding times might affect method performance. PFAS were analyzed in tap water samples collected at a large spatial scale in Quebec, Canada, covering 376 municipalities within 17 administrative regions. Target and nontarget screening revealed the presence of 31 and 23 compounds, respectively, representing 24 homolog classes. Overall, 99.3% of the tap water samples were positive for at least one PFAS, and the ƩPFAS ranged from below detection limits to 108 ng/L (95^th percentile: 13 ng/L). On average, ƩPFAS was 12 times higher in tap water produced from surface water than groundwater; however, 6 of the top 10 contaminated locations were groundwater-based. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) had high detection rates (88% and 80%, respectively). PFOS (median: 0.15 ng/L; max: 13 ng/L) and PFOA (median: 0.27 ng/L; max: 8.1 ng/L) remained much lower than current Health Canada guidelines but higher than USEPA’s interim updated health advisories. Short-chain (C3-C6) perfluoroalkyl sulfonamides were also recurrent, especially the C4 homolog (FBSA: detection rate of 50%). The 6:2 fluorotelomer sulfonyl propanoamido dimethyl ethyl sulfonate (6:2 FTSO2PrAd-DiMeEtS) was locally detected at ∼15 ng/L and recurred in 8% of our samples. Multiple PFAS that are most likely to originate from aqueous film-forming foams were also reported for the first time in tap water, including X:3 and X:1:2 fluorotelomer betaines, hydroxylated X:2 fluorotelomer sulfonates, N-trimethylammoniopropyl perfluoroalkane sulfonamides (TAmPr-FHxSA and TAmPr-FOSA), and N-sulfopropyl dimethylammoniopropyl perfluoroalkane sulfonamidopropyl sulfonates (N-SPAmP-FPeSAPS and N-SPAmP-FHxSAPS).”

Hi all…Health Canada has been busy lately releasing new guidelines and guidance. The latest will, I’m sure, generate a lot of discussion. In a release dated February 7, Health Canada is proposing an objective of 30 ng/L for the sum of total per- and polyfluoroalkyl substances (PFAS) detected in drinking water. Total is defined by a couple of USEPA methods or a method that can detect at least 18 PFAS. Also of note is that they state “For the purposes of this proposed objective, a result of non-detect is considered to have a value of zero.” The consultation period ends on April 12.

https://www.canada.ca/en/health-canada/programs/consultation-draft-objective-per-polyfluoroalkyl-substances-canadian-drinking-water/overview.html

The existing guidelines are 0.2 ng/L for PFOA and 0.6 ng/L for PFOS. A full list of current screening values is available.

Bill

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Draft objective for per- and polyfluoroalkyl substances in Canadian drinking water

Objective for Public Consultation

Download in PDF format
(390 KB, 25 pages)

Proposed objective value: “To reduce exposure from drinking water, an objective of 30 ng/L is proposed for the sum of total per- and polyfluoroalkyl substances (PFAS) detected in drinking water. Total PFAS should be calculated using the full list of substances in either the United States Environmental Protection Agency (U.S. EPA) Method 533 or U.S. EPA Method 537.1, or both (see Appendix A). A jurisdiction could also validate and apply an alternate analytical method that quantifies a minimum of 18 PFAS. For the purposes of this proposed objective, a result of non-detect is considered to have a value of zero. It is recommended that treatment plants strive to maintain PFAS concentrations in drinking water as low as reasonably achievable (ALARA).”

Hi all…there are a lot of warnings about the impact of climate change on drinking water safety, especially as it pertains to cyanobacteria and their toxins (for example microcystin, cylindrospermopsin, and anatoxin). A paper recently published in the journal Water Research provides some hard evidence to suggest that climate change is related to, or associated with, cyanobacterial occurrence (it is hard to even describe the connection between the two given some uncertainties). Aside from the paper title, what got my attention is the statement that reads “A steady increase in the abundance of Microcystis (as potential toxin producers) during the past thirty years was correlated with increasing temperatures and declining wind speeds, but not with temporal trends in lake water nutrient concentrations, highlighting recent climate effects on potentially increasing toxin-producing taxa.” It will be interesting to see how this paper is received.

Bill

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Ancient DNA reveals potentially toxic cyanobacteria increasing with climate change

Jifeng Zhang, Kun Shi, Hans W. Paerl, Kathleen M. Rühland, Yanli Yuan, Rong Wang, Jie Chen, Mengjuan Ge, Lingling Zheng, Zhiping Zhang, BoqiangQin, Jianbao Liu, and John P. Smol

Water Research Volume 229, 1 February 2023, 119435, doi: https://doi.org/10.1016/j.watres.2022.119435

Abstract

“Cyanobacterial blooms in freshwater systems are a global threat to human and aquatic ecosystem health, exhibiting particularly harmful effects when toxin-producing taxa are present. While climatic change and nutrient over-enrichment control the global expansion of total cyanobacterial blooms, it remains unknown to what extent this expansion reflected cyanobacterial assemblage due to the scarcity of long-term monitoring data. Here we use high-throughput sequencing of sedimentary DNA to track 100 years of changes in cyanobacterial community in hyper-eutrophic Lake Taihu, China’s third largest freshwater lake and the key water source for ~30 million people. A steady increase in the abundance of Microcystis (as potential toxin producers) during the past thirty years was correlated with increasing temperatures and declining wind speeds, but not with temporal trends in lake water nutrient concentrations, highlighting recent climate effects on potentially increasing toxin-producing taxa. The socio-environmental repercussions of these findings are worrisome as continued anthropogenic climate change may counteract nutrient amelioration efforts in this critical freshwater resource.”

Hi all…in addition to the release of Health Canada’s “draft guidance on sampling and mitigation measures for controlling corrosion” for comment on December 24, there was another request for public comment. It is entitled “Draft technical document guidelines for Canadian drinking water quality – Antimony”. It is proposed that a maximum acceptable concentration (MAC) of 0.006 mg/L (6 μg/L) be established for antimony in drinking water. This is the existing MAC (i.e. unchanged). The text I have highlighted in yellow below briefly explains the need for public comment given that there is no change in the MAC being proposed. Comments are due by March 8, 2023.

Draft technical document guidelines for Canadian drinking water quality – Antimony

https://www.canada.ca/en/health-canada/programs/consultation-draft-technical-document-guidelines-canadian-drinking-water-quality-antimony/overview.html

Purpose of consultation

“This guideline technical document evaluated the available information on antimony with the intent of updating the guidelines for antimony in drinking water. The purpose of this consultation is to solicit comments on the proposed guidelines, on the approach used for its development, and on the potential impacts of implementing them.

The existing guideline technical document on antimony, developed in 1999, recommended a maximum acceptable concentration (MAC) of 0.006 mg/L (6 µg/L) based on histological changes observed in the rat in a study by Poon et al. (1998). It was risk managed to take into consideration limitations in treatment technology. This document proposes a MAC of 0.006 mg/L (6 µg/L) for antimony in drinking water, based on histological changes in the liver and changes in serum biochemistry in the rat in the same study by Poon et al. (1998). The updated proposed MAC is risk managed to take into consideration treatment challenges of lowering the MAC (especially for private wells and small systems) without significant increase in health protection. The document was reviewed by external experts and subsequently revised.”

Please send comments (with rationale, where required) to Health Canada via email at water-eau@hc-sc.gc.ca.

Bill

Hi all…Health Canada has posted a request for public comment on the draft document entitled “Guidance on sampling and mitigation measures for controlling corrosion.” They indicate that it “has been developed with the intent to provide regulatory authorities and decision-makers with guidance on sampling and mitigation measures for controlling corrosion in drinking water distribution systems. The document is being made available for a 60-day public consultation period.” Note that the deadline for public comment is Feb 15, 2023.

Comments can be sent via email to Health Canada at water-eau@hc-sc.gc.ca.

Bill

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Draft guidance on sampling and mitigation measures for controlling corrosion

PDF 

Executive summary

“Corrosion is a common issue in Canadian drinking water supplies. Corrosion is the deterioration of a material, usually a metal, that results from a reaction with its environment. In drinking water distribution systems, materials that could be affected by corrosion and release increased amounts of contaminants (specifically metals such as lead) include metal pipes (e.g., lead service lines) and fittings. There are no direct health effects linked to corrosion in distribution systems, but corrosion may cause the release of contaminants that would be a concern for the health of Canadians. The main contaminant of concern is lead, for which the key health endpoint of concern is the reduction in intelligence quotient (IQ) scores in children. Lead is used as the trigger to initiate corrosion control programs to control or mitigate its release. Corrosion control treatment can effectively minimize lead concentrations at the point of consumption. However, when water is supplied through a lead service line, treatment alone may not be sufficient to reduce lead to concentrations below Health Canada’s maximum allowable concentration (MAC) of 0.005 mg/L (5 µg/L). Therefore, the removal of the full lead service line is likely the most effective and most permanent solution.

In this document, corrosion refers to the internal corrosion of the distribution system and not external corrosion of the infrastructure. Additionally, “corrosion control” refers to the action of controlling or mitigating the release of metals, primarily lead, that results from the corrosion of materials in drinking water distribution systems. Information on components of a corrosion control program is provided. However, detailed operational aspects such as developing a corrosion plan or removal of lead service lines are outside the scope of this document…Microbiologically influenced corrosion is briefly discussed but detailed information is beyond the scope of this document.

Although corrosion itself cannot readily be measured by any single reliable method, the lead levels at a consumer’s tap can be used as an indication of corrosion. Corrosion control programs will vary depending on the responsible authority. They can range from extensive system-wide programs implemented by the water utility to localized programs implemented by a building owner, to ensure a safe and healthy environment for the occupants of residential and non-residential buildings.

This guidance document was prepared in collaboration with the Federal‑Provincial‑Territorial Committee on Drinking Water and assesses all available information on corrosion control in the context of drinking water quality and safety.”

Assessment

“The intent of this document is to provide responsible authorities, such as municipalities and water suppliers, with guidance on assessing corrosion and implementing corrosion control measures for distribution systems in residential settings to minimize exposure to lead. It also provides sampling protocols and corrective measures for multi-dwelling buildings, schools, day care facilities and office buildings for those authorities, such as school boards, building owners or employers, that are responsible for the health and safety of the occupants of such buildings.

This document outlines the steps that should be taken to reduce population exposure to lead, which may also reduce the consumer’s exposure to other corrosion-related contaminants such as copper. Concerns related to other contaminants whose concentrations may be affected by corrosion, such as iron, are also briefly discussed.

This guidance is intended to complement the information provided in the Guideline Technical Document of the Guidelines for Canadian Drinking Water Quality for lead.”

Hi all…a just published paper in the journal ‘Environmental Health Perspectives’ estimates potential bladder cases associated with chlorinated disinfection byproducts (DBPs) in the US and reports that “despite significant reductions in exposure over the past several decades, our study suggests that ∼10% of the bladder cancer cases in the United States may still be attributed to exposure to DBPs found in drinking water systems.”

The toxicology and regulation of THMs has been widely discussed since their identification in treated water and this is acknowledged in the conclusions which state “Despite the increased weight of evidence established in recent years toward inferring a causal relationship between DBP exposure and bladder cancer, more work is needed to understand the possible mechanisms involved in that relationship, clarify different sources of uncertainty, and address the utility of THM4 as a surrogate measure of risk from the most relevant DBP mixtures of toxicological interest.”

This is an open access paper and can be downloaded free of charge at: https://doi.org/10.1289/EHP9985

Bill

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Estimating National Exposures and Potential Bladder Cancer Cases Associated with Chlorination DBPs in U.S. Drinking Water

Richard J. Weisman, Austin Heinrich, Frank Letkiewicz, Michael Messner, Kirsten Studer, Lili Wang, and Stig Regli

Environmental Health Perspectives, 130:8, Online publication date: 1-Aug-2022. https://doi.org/10.1289/EHP9985

“Abstract

Background:

Disinfection byproducts (DBPs) in public water systems (PWS) are an unintended consequence resulting from reactions between mostly chlorine-based disinfectants and organic and inorganic compounds in source waters. Epidemiology studies have shown that exposure to DBP (specifically trihalomethanes) was associated with an increased risk of bladder cancer.

Objective:

Our goal was to characterize the relative differences in exposures and estimated potential bladder cancer risks for people served by different strata of PWS in the United States and to evaluate uncertainties associated with these estimates.

Methods:

We stratified PWS by source water type (surface vs. groundwater) and population served (large, medium, and small) and calculated population-weighted mean trihalomethane-4 (THM4) concentrations for each stratum. For each stratum, we calculated a population attributable risk (PAR) for bladder cancer using odds ratios derived from published pooled epidemiology estimates as a function of the mean THM4 concentration and the fraction of the total U.S. population served by each stratum of systems. We then applied the stratum-specific PARs to the total annual number of new bladder cancer cases in the U.S. population to estimate bladder cancer incidence in each stratum.

Results:

Our results show that approximately 8,000 of the 79,000 annual bladder cancer cases in the United States were potentially attributable to DBPs in drinking water systems. The estimated attributable cases vary based on source water type and system size. Approximately 74% of the estimated attributable cases were from surface water systems serving populations of >10,000 people. We also identified several uncertainties that may affect the results from this study, primarily related to the use of THM4 as a surrogate measure for DBPs relevant to bladder cancer.

Discussion:

Despite significant reductions in exposure over the past several decades, our study suggests that ∼10% of the bladder cancer cases in the United States may still be attributed to exposure to DBPs found in drinking water systems.”

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William (Bill) B. Anderson, Ph.D.

Hi all…following up from the message below, it should be noted that SARS-CoV-2 virus testing is done using raw sewage, not treated effluent (as will presumably be done for polio). Monitoring wastewater treated effluent would be a departure from the current procedure.

Bill

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From: Bill Anderson
Sent: August 12, 2022 9:32 AM
Subject: Canada to start testing some wastewater for polio as soon as possible

Hi all…as is known, wastewater contains pathogenic viruses and their genetic material. With the development of strategies and methods for collecting, analyzing, and tracking the SARS-CoV-2 virus, the door has been opened to monitor for other viruses. CBC is reporting that testing for polio and monkeypox viruses will soon be conducted in select municipalities. It is also well known that polioviruses are shed following vaccination with oral polio vaccine (OPV), vs. the inactivated polio vaccine (IPV) used in North America. Like SARS-CoV-2, OPV can mutate and some have regained pathogenic capabilities. While the virus has been on the verge of being completely eradicated it is still found in a few countries and could therefore be imported into previously eradicated jurisdictions.

There are a number of positive public health implications associated with monitoring if appropriate actions are taken. While drinking water treatment plants are designed to remove pathogens, including viruses, it would be helpful to know what ‘live’ viruses may be escaping wastewater treatment and in what concentrations to include in risk analysis and response. For more information on waterborne viruses see Health Canada’s Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Enteric Viruses.

Bill

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Canada to start testing some wastewater for polio as soon as possible

CBC Aug 11 2022

https://www.cbc.ca/news/health/canada-to-start-testing-some-wastewater-for-polio-as-soon-as-possible-1.6548651

“After new reports of polio cases abroad, and virus samples in the wastewater of several other developed countries, Canada intends to start testing wastewater from a number of cities “as soon as possible,” CBC News has learned.”

Results:

Our results show that approximately 8,000 of the 79,000 annual bladder cancer cases in the United States were potentially attributable to DBPs in drinking water systems. The estimated attributable cases vary based on source water type and system size. Approximately 74% of the estimated attributable cases were from surface water systems serving populations of >10,000 people. We also identified several uncertainties that may affect the results from this study, primarily related to the use of THM4 as a surrogate measure for DBPs relevant to bladder cancer.

Discussion:

Despite significant reductions in exposure over the past several decades, our study suggests that ∼10% of the bladder cancer cases in the United States may still be attributed to exposure to DBPs found in drinking water systems.”

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William (Bill) B. Anderson, Ph.D.