Boil Water / Do Not Drink Advisories – WaterSTP

Analysis of building plumbing system flushing practices and communications

Bill Anderson — Fri, 03 May 2019 19:51:38 +0000

Hi all…an interesting paper dealing with contamination incidents in distribution systems prompting public agencies and drinking water utilities to issue do-not-drink and do-not-use advisories has been recently published. The authors note that “after a contaminant is cleared from distribution mains, consumers are often directed to flush their plumbing. However, little validated guidance and few evaluated communications strategies are available on using flushing to decontaminate building water systems.” They report that “expert elicitation was used to assess existing flushing guidance and develop validated flushing guidance and communications for single-family residences. The resulting guidance recommends progressively opening all cold-water taps from the closest to point of entry to the furthest and allowing the water to run for at least 20 minutes. Hot-water taps should be opened progressively and run for at least 75 minutes.”

The paper is worth reading if you are wondering about guidance for such events. For those of you attending Ontario’s Water Conference & Trade Show in Ottawa next week I hope that you enjoy it, I know I always do!

Bill

Analysis of building plumbing system flushing practices and communications

Lisa Ragain, Sheldon Masters, Timothy A. Bartrand, Jennifer L. Clancy and Andrew J. Whelton
J Water Health (2019) 17 (2): 196-203
https://iwaponline.com/jwh/article/17/2/196/65542/Analysis-of-building-plumbing-system-flushing

Abstract

“Drinking water distribution system contamination incidents can prompt public agencies and drinking water utilities to issue do-not-drink and do-not-use advisories. After the contaminant is cleared from distribution mains, consumers are often directed to flush their plumbing. However, little validated guidance and few evaluated communications strategies are available on using flushing to decontaminate building water systems. Additionally, limited data support the effectiveness of current practices and recommendations. In this study, expert elicitation was used to assess existing flushing guidance and develop validated flushing guidance and communications for single-family residences. The resulting guidance recommends progressively opening all cold-water taps from the closest to point of entry to the furthest and allowing the water to run for at least 20 minutes. Hot-water taps should be opened progressively and run for at least 75 minutes. The guidance language and format conformed to grade-level and readability scores within recommended health communication ranges. The readability of eight other flushing guidance documents was also evaluated for contamination incidents from 2008–2015. Seven were written at a 10th–12th grade level, above the 6th–7th grade level recommended for health communications.”

BOIL WATER/DO NOT DRINK ADVISORIES

The post Analysis of building plumbing system flushing practices and communications appeared first on WaterSTP.

Ecophysiological Examination of the Lake Erie Microcystis Bloom in 2014: Linkages between Biology and the Water Supply Shutdown of Toledo

Bill Anderson — Tue, 11 Jul 2017 17:00:11 +0000

Hi all…in a follow-up study on the Toledo Ohio 2014 Microcystis bloom event which led to a “do not drink advisory” for more than 400,000 residents,researchers have reported that a virus may have been involved in the crisis and they warn that for utilities prone to experiencing such blooms that more stringent raw water monitoring may be necessary. Cell bound cyanotoxins (at least in the case of microcystins and anatoxin-a) usually aren’t released until the cells experience stress or die. As with other bacteria, there exist viruses which can attack cyanobacteria (cyanophage) leading to the release of toxin and if within range of a drinking water intake can be problematic. The study authors documented the viral infection by sequencing RNA from the Toledo water samples and they used computer models to simulate how the cyanobacterial blooms moved through water. They also warn that this scenario was not atypical of reoccurring Lake Erie blooms and thus may reoccur in the future.

Bill

Ecophysiological Examination of the Lake Erie Microcystis Bloom in 2014: Linkages between Biology and the Water Supply Shutdown of Toledo

Steffen et al

http://pubs.acs.org/doi/abs/10.1021/acs.est.7b00856

Environ. Sci. Technol. 2017, 51(12), 6745−6755

ABSTRACT: “Annual cyanobacterial blooms dominated by Microcystis have occurred in western Lake Erie (U.S./Canada) during summer months since 1995. The production of toxins by bloom-forming cyanobacteria can lead to drinking water crises, such as the one experienced by the city of Toledo in August of 2014, when the city was rendered without drinking water for >2 days. It is important to understand the conditions and environmental cues that were driving this specific bloom to provide a scientific framework for management of future bloom events. To this end, samples were collected and metatranscriptomes generated coincident with the collection of environmental metrics for eight sites located in the western basin of Lake Erie, including a station proximal to the water intake for the city of Toledo. These data were used to generate a basin-wide ecophysiological fingerprint of Lake Erie Microcystis populations in August 2014 for comparison to previous bloom communities. Our observations and analyses indicate that, at the time of sample collection, Microcystis populations were under dual nitrogen (N) and phosphorus (P) stress, as genes involved in scavenging of these nutrients were being actively transcribed. Targeted analysis of urea transport and hydrolysis suggests a potentially important role for exogenous urea as a nitrogen source during the 2014 event. Finally, simulation data suggest a wind event caused microcystin-rich water from Maumee Bay to be transported east along the southern shoreline past the Toledo water intake. Coupled with a significant cyanophage infection, these results reveal that a combination of biological and environmental factors led to the disruption of the Toledo water supply. This scenario was not atypical of reoccurring Lake Erie blooms and thus may reoccur in the future.”

The post Ecophysiological Examination of the Lake Erie Microcystis Bloom in 2014: Linkages between Biology and the Water Supply Shutdown of Toledo appeared first on WaterSTP.

EPA Issues Health Advisory Level for Perfluorinated Compounds in Drinking Water

Bill Anderson — Wed, 25 May 2016 13:09:47 +0000

Hi all…The USEPA has released health advisories for the perfluorinated compounds perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). As far as I am aware, there are no advisories, guidelines, or standards in Canada at this time. They are very difficult to remove from drinking water.

Bill

______________________________________

Drinking Water Health Advisories for PFOA and PFOS

“EPA has established health advisories for PFOA and PFOS based on the agency’s assessment of the latest peer-reviewed science to provide drinking water system operators, and state, tribal and local officials who have the primary responsibility for overseeing these systems, with information on the health risks of these chemicals, so they can take the appropriate actions to protect their residents. EPA is committed to supporting states and public water systems as they determine the appropriate steps to reduce exposure to PFOA and PFOS in drinking water. As science on health effects of these chemicals evolves, EPA will continue to evaluate new evidence. To provide Americans, including the most sensitive populations, with a margin of protection from a lifetime of exposure to PFOA and PFOS from drinking water, EPA has established the health advisory levels at 70 ng/L (parts per trillion).“ [EPA’s health advisories are non-enforceable and non-regulatory and provide technical information to states agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination.]

https://www.epa.gov/ground-water-and-drinking-water/drinking-water-health-advisories-pfoa-and-pfos

https://www.epa.gov/sites/production/files/2016-05/documents/drinkingwaterhealthadvisories_pfoa_pfos_5_19_16.final_.1.pdf (fact sheet)

________________________________________

If you’re interested in learning more about PFOA and PFOS we’re doing research in the this area and the paper below can bring you up to speed. Let me know if you can’t access it.

Behaviour and fate of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in drinking water treatment: A review

Mohammad Feisal Rahman, Sigrid Peldszus, and William B. Anderson

Water Research, 50(1):318–340. http://www.sciencedirect.com/science/article/pii/S0043135413008518

ABSTRACT

“This article reviews perfluoroalkyl and polyfluoroalkyl substance (PFAS) characteristics, their occurrence in surface water, and their fate in drinking water treatment processes. PFASs have been detected globally in the aquatic environment including drinking water at trace concentrations and due, in part, to their persistence in human tissue some are being investigated for regulation. They are aliphatic compounds containing saturated carbon-fluorine bonds and are resistant to chemical, physical, and biological degradation. Functional groups, carbon chain length, and hydrophilicity/hydrophobicity are some of the important structural properties of PFASs that affect their fate during drinking water treatment. Full-scale drinking water treatment plant occurrence data indicate that PFASs, if present in raw water, are not substantially removed by most drinking water treatment processes including coagulation, flocculation, sedimentation, filtration, biofiltration, oxidation (chlorination, ozonation, AOPs), UV irradiation, and low pressure membranes. Early observations suggest that activated carbon adsorption, ion exchange, and high pressure membrane filtration may be effective in controlling these contaminants. However, branched isomers and the increasingly used shorter chain PFAS replacement products may be problematic as it pertains to the accurate assessment of PFAS behaviour through drinking water treatment processes since only limited information is available for these PFASs.”

The post EPA Issues Health Advisory Level for Perfluorinated Compounds in Drinking Water appeared first on WaterSTP.