Hi all…an interesting paper on an “approach to classify a school’s lead risk, which could help water utilities and schools prioritizing testing and remediation efforts,” recently appeared in the journal ‘Environmental Science & Technology Letters’. The authors found that “fixtures releasing lead >1 ppb occurred in >90% of schools and represented 58% of first draws and 33% of 30-s flushed samples” vs. 12% of fixtures which had first draw lead >15 ppb and 3% after a 30 s flushing. The data were collected from the Massachusetts ‘Lead in School Drinking Water Database’.

If you are able to download the paper, Figure 1 provides the lead concentration in first draw and flushed samples for water fountains (n = 8,963 and 5,274) and non-water fountain fixtures (n = 13,309 and 11,260) at schools where fixture type was identified (n = 738). The large numbers of samples analyzed adds to the general reliability of the approach and findings. For more information on the USEPA proposed Revisions to the Lead and Copper Rule (LCR) see: https://www.epa.gov/ground-water-and-drinking-water/proposed-revisions-lead-and-copper-rule. For comparison, the Health Canada maximum acceptable concentration (MAC) for total lead in drinking water is 0.005 mg/L (5 μg/L), “based on a sample of water taken at the tap and using the appropriate protocol for the type of building being sampled. Every effort should be made to maintain lead levels in drinking water as low as reasonably achievable.”

Bill

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Using the Lead and Copper Rule Revisions Five-Sample Approach to Identify Schools with Increased Lead in Drinking Water Risks

McNamara Rome, Stephen Estes-Smargiassi, Sheldon V. Masters, Alan Roberson, John E. Tobiason, R. Edward Beighley, and Kelsey J. Pieper

Environ. Sci. Technol. Lett. 2022, 9, 1, 84–89. https://doi.org/10.1021/acs.estlett.1c00845

 Abstract

“Despite public concern, the risk of lead exposure from schools remains poorly understood. The Lead and Copper Rule Revisions (LCRR) include, for the first time, a five-sample lead testing requirement for all elementary schools. However, the United States Environmental Protection Agency does not define school-wide lead risk or provide clear guidance on how results should be interpreted. Using the Massachusetts Lead in School Drinking Water Database, we explored the application of the LCRR sampling approach and provide insight into the magnitude and distribution of lead in water in Massachusetts public schools. We observed that 12% of fixtures had first draw lead >15 ppb and 3% after a 30 s flushing. Approximately 90% of fixtures with lead >15 ppb were clustered in 34% of schools. We determined a school-wide 90th percentile of 10 ppb closely approximated this clustering of problem fixtures and were able to identify schools with problem fixtures using the five-sample results with a confidence >90%. Fixtures releasing lead >1 ppb occurred in >90% of schools and represented 58% of first draws and 33% of 30-s flushed samples. Overall, our study provides an approach to classify a school’s lead risk, which could help water utilities and schools prioritizing testing and remediation efforts.”

Hi all…the existence of opportunistic pathogens in drinking water distribution systems and premise plumbing (DWPI) has been known for decades. Attention has been focused primarily on Legionella but owing to a variety of factors, solutions are a patchwork at best. Below are two recent papers on the topic.

1. The first has just been published in the journal ‘Water Research’ asking the question “how can all microorganisms of concern in drinking water distribution systems and premise plumbing be managed simultaneously?” They conclude “while a single solution that creates a “zero-risk” plumbing system is not possible, increased cooperation and multiple DWPI consideration will allow for informed balancing of risk and consequences.” The full abstract is below.
2. A second very relevant paper entitled “Legionella and other opportunistic pathogens in full-scale chloraminated municipal drinking water distribution systems” was published earlier this fall. It “aimed to quantify how physicochemical parameters, mainly monochloramine residual concentration, hydraulic residence time (HRT), and seasonality, affected the occurrence and concentrations of four common opportunistic pathogens (OPs) (Legionella, Mycobacterium, Pseudomonas, and an amoeba [I am not familiar with] Vermamoeba vermiformis) in four full-scale DWDSs in the US. Legionella as a dominant OP occurred in 93.8% of the 64 sampling events and had a mean density of 4.27 × 10⁵ genome copies per liter. Legionella positively correlated with Mycobacterium, Pseudomonas, and total bacteria. Multiple regression with data from the four DWDSs showed that Legionella had significant correlations with total chlorine residual level, free ammonia concentration, and trihalomethane concentration. They concluded that Legionella is a promising indicator of water-based OPs, reflecting microbial water quality in chloraminated DWDS.” While this remains to be confirmed in other systems, it is a promising development. I have not reproduced the abstract for this one, it is available at https://doi.org/10.1016/j.watres.2021.117571.

Bill________________________________________________________

Tenets of a Holistic Approach to Drinking Water-Associated Pathogen Research, Management, and Communication

Caitlin Proctor, Emily Garner, Kerry A. Hamilton, Nicholas J. Ashbolt, Lindsay J. Caverly, Joseph O. Falkinham III, Charles N. Haas, Michele Prevost, Rebecca Prevots, Amy Pruden, Lutgarde Raski, Janet Stout, Sarah-Jane Haig

Water Research (2021), doi: https://doi.org/10.1016/j.watres.2021.117997

ABSTRACT

“In recent years, drinking water-associated pathogens that can cause infections in immunocompromised or otherwise susceptible individuals (henceforth referred to as DWPI), sometimes referred to as opportunistic pathogens or opportunistic premise plumbing pathogens, have received considerable attention. DWPI research has largely been conducted by experts focusing on specific microorganisms or within silos of expertise. The resulting mitigation approaches optimized for a single microorganism may have unintended consequences and trade-offs for other DWPI or other interests (e.g., energy costs and conservation). For example, the ecological and epidemiological issues characteristic of Legionella pneumophila diverge from those relevant for Mycobacterium avium and other nontuberculous mycobacteria. Recent advances in understanding DWPI as part of a complex microbial ecosystem inhabiting drinking water systems continues to reveal additional challenges: namely, how can all microorganisms of concern be managed simultaneously? In order to protect public health, we must take a more holistic approach in all aspects of the field, including basic research, monitoring methods, risk-based mitigation techniques, and policy. A holistic approach will (i) target multiple microorganisms simultaneously, (ii) involve experts across several disciplines, and (iii) communicate results across disciplines and more broadly, proactively addressing source water-to-customer system management.”

Hi all…as the Monty Python show used to say, “and now for something completely different.” I always have many papers set aside to send out to this list. By far the topics generating the most recent interest among researchers, regulators, and drinking water professionals are cyanotoxins, PFAS, and microplastics but I thought I’d take a break from these. It turns out that some researchers from Denmark are studying phytotoxins – those produced by plants – from the potential of them being contaminants with the potential to impair drinking water quality. Of several different phytotoxins spiked into groundwater and ultimately treated by 5 different filter types, two of them, jacobine N-oxide and senecionine N-oxide, were found to be non-biodegradable. They were also able to identify some degradation products.

The paper is open access if you want to learn more.

Bill

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Removal of phytotoxins in filter sand used for drinking water treatment

Natasa Skrbic Mrkajic, Jawameer R.Hama, Bjarne W. Strobel, Hans Chr. B. Hansen, Lars Holm Rasmussen, Ann-Katrin Pedersen, Sarah C.B. Christensen, Mathilde J.Hedegaard

https://www.sciencedirect.com/science/article/pii/S0043135421008058?dgcid=raven_sd_via_email

Water Research Volume 205, 15 October 2021, 117610

Abstract

“Phytotoxins – toxins produced by plants – are contaminants with the potential to impair drinking water quality. They encompass a large group of toxic, partially persistent compounds that have been detected in seepage waters and in shallow wells used for drinking water production. If phytotoxins enter wells used for drinking water production, it is essential to know if the drinking water treatment processes will remove them from the water phase. However, it is currently unknown whether phytotoxins remain stable during traditional groundwater treatment using sand filters as the main treatment process. The objective of this study is to investigate removal potential of phytotoxins in biological sand filters and to asses if the removal potential is similar at different waterworks.

Microcosms were set up with filter sand and drinking water collected at different groundwater-based waterworks. To be able to monitor phytotoxin removal ptaquiloside, caudatoside, gramine, sparteine, jacobine N-oxide, senecionine N-oxide and caffeine were applied at initial concentrations of 300 µg L^-1, which is approx. two orders of magnitude higher than currently detected in environment, but expected to cover extreme environmental conditions. Removal was monitored over a period of 14 days. Despite the high initial concentration, all filter sands removed ptaquiloside and caudatoside completely from the water phase and at waterworks where pellet softening was implemented (pH 8.4) prior to rapid sand filtration, complete removal occurred within the first 30 min. All filter sands removed gramine and sparteine, primarily by a biological process, while jacobine N-oxide, senecionine N-oxide and caffeine were recalcitrant in the filter sands. During degradation of ptaquiloside and caudatoside we observed formation and subsequent removal of degradation products pterosin B and A. Filter sands with the highest removal potential were characterised by high contents of deposited iron and manganese oxides and hence large specific surface areas. Difference between bacterial communities investigated by 16S rRNA gene analyses did not explain different removal in the filter sands.

All five investigated filter sands showed similar degradation patterns regardless of water chemistry and waterworks of origin. In drinking water treatment systems biological sand filters might therefore remove phytotoxin contaminants such as ptaquiloside, caudatoside, gramine, sparteine, while for other compounds e.g. jacobine N-oxide, senecionine N-oxide further investigations involving more advanced treatment options are needed.”

Hi all…a just released article entitled “Drinking Water Disinfection by-Products and Congenital Malformations: A Nationwide Register-Based Prospective Study” has appeared in the journal ‘Environmental Health Perspectives’. The study examined 623,468 births and concluded that “TTHM exposure was associated with the increased risk of malformations of the nervous system, urinary system, genitals, and limbs in areas exclusively using chloramine. An association between chloramine-related chlorination by-products and congenital malformations has not previously been highlighted and needs further attention.”

Wow! I have never seen a study linking THMs in chloraminated water with any of the health impacts they describe, let alone all (and in particular THMs in chloraminated water as the level of these is relatively low compared with chlorinated systems). Even more surprizing is the report that these associations were NOT seen in plants using “exclusively hypochlorite as the primary water treatment method.” The article is free to download. Regulators and drinking water providers may want to be ready to respond in the event this study gets wider publicity. I haven’t had time to read this one. It makes me wonder if the THM concentrations were effectively a surrogate for another DBP grouping such as the nitrogen-based DBPs. If any of you read it and have comments, please let me know. Thanks!

Bill

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Drinking Water Disinfection by-Products and Congenital Malformations: A Nationwide Register-Based Prospective Study

Melle Säve-Söderbergh, Jonas Toljander, Carolina Donat-Vargas, and Agneta Åkesson

Environmental Health Perspectives, Vol. 129, No. 9 Published:29 September 2021CID: 097012https://doi.org/10.1289/EHP9122

https://ehp.niehs.nih.gov/doi/pdf/10.1289/EHP9122

“BACKGROUND: Drinking water chlorination by-products have been associated with adverse reproductive outcomes, although the findings for congenital malformations are still inconclusive.

OBJECTIVE: We conducted a nationwide register-based prospective study to assess whether first trimester maternal exposure to the four most common trihalomethanes [total trihalomethanes (TTHM)] via municipal drinking water was associated with risk of congenital malformation among newborns.

 METHODS: We included all births during 2005–2015 (live and stillbirths) of mothers residing in Swedish localities having >10,000 inhabitants, two or fewer operating water works, and sufficient municipal TTHM monitoring data. Individual maternal first trimester exposure was obtained by linking TTHM measurements to residential information, categorized into no chlorination and <5, 5-15, and  >15 µg TTHM/L. We also made chlorination treatment-specific analyses (exclusive use of chloramine or hypochlorite). Outcomes and covariates were obtained via linkage to health care and administrative registers. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by logistic regression.

RESULTS: Based on 623,468 births and a prevalence of congenital malformation of ∼2 cases/100 births, we observed associations between TTHM exposure in areas using chloramine and malformations of the nervous system (OR = 1:82; 95% CI: 1.07, 3.12), urinary system (OR = 2:06; 95% CI: 1.53, 2.78), genitals (OR = 1:77; 95% CI: 1.38, 2.26), and limbs (OR = 1:34; 95% CI: 1.10, 1.64), comparing the highest exposed category with the unexposed. No associations were observed in areas using exclusively hypochlorite as the primary water treatment method. By contrast, for malformations of the heart, a significant inverse association was observed only in areas using hypochlorite.

DISCUSSION: TTHM exposure was associated with the increased risk of malformations of the nervous system, urinary system, genitals, and limbs in areas exclusively using chloramine. An association between chloramine-related chlorination by-products and congenital malformations has not previously been highlighted and needs further attention. https://doi.org/10.1289/EHP9122 “

Hi all…a paper on nanoparticles has just appeared in the journal ACS EST Water. It provides baseline concentrations and sizes for typical occurrence of natural and anthropogenic (manufactured) nanoparticles (NPs) including gold, cerium, titanium, and palladium (Au, Ce, Ti, and Pd) in US drinking water sources.

The authors conclude that “NP size distributions of these surface water samples could rarely be described adequately with log-normal curve fitting, in contradiction to the common expectation that particle size is lognormally distributed in nature. There was no apparent geography-based difference, or trend, in distributions of NP sizes found in all the samples. A great amount of temporal variability was observed, suggesting that flow conditions, precipitation, and point-source release events may strongly impact NP concentrations on the day of sampling. This supports the hypothesis that [engineered nanoparticles] ENP hot spots may occur at different points in time depending on local sources and release factors. This study provides baseline concentrations and sizes for typical occurrence of natural and anthropogenic NPs (Au, Ce, Ti, and Pd) in drinking water sources on a regional geographic scale. As the usage of these elements in nanomaterials increases, monitoring their levels and fluctuations will assist in environmental and human health risk assessment.”

Prior to reading this, I didn’t stop to consider that “naturally” present nanoparticles can potentially complicate source tracking and other studies. The authors reported that of the elements examined, Ti has the highest natural abundance, followed by Ce, then Au, and Pd.

Bill

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Quantifying Nanoparticle Associated Ti, Ce, Au, and Pd Occurrence in 35 U.S. Surface Waters

https://doi.org/10.1021/acsestwater.1c00206 ACS EST Water XXXX, XXX, XXX−XXX

Logan N. Rand, Kenneth Flores, Naushita Sharma, Jorge Gardea-Torresdey, and Paul Westerhoff

ABSTRACT

“Mass flux models have predicted environmental concentrations of released engineered nanoparticles (ENPs), but their validation with field studies at high geographic scale has been limited. Additionally, baseline levels of natural and incidental nanoparticle (NP) occurrence are not well-established. This study begins to address these knowledge gaps by investigating the Au, Ce, Ti, and Pd NP content of 241 water samples from 35 drinking water sources across the U.S. over 6–9 monthsusing single particle inductively coupled plasma-mass spectrometry. Ce and Ti NPs were commonly detected, with Ce concentrations (0.3–230 μg L^–1) exceeding both ENP predictions and reports of natural abundance. The Ti NP concentrations (3–2,400 μg L^–1) were greater than modeled ENP release and similar to the expected natural abundance. Although Au and Pd NPs were rarely detected, they were present at parts per billion levels in some samples. The NP concentrations and sizes did not differ between geographic regions but were highly variable at individual sites over time, suggesting that local changes to release rates and precipitation may cause temporary hot spots. The regional NP concentrations and sizes provided here will be useful to inform continued ENP release and risk assessment studies.”

Hi all…over the past couple of decades many drinking water treatment plants have added UV as a treatment, particularly for protozoan (oo)cysts such as those of Cryptosporidium, which are resistant to chlorine. While oocysts are the primary target it is important to recognize that UV is an important technology for the inactivation of a large variety of pathogens. An article published in the Journal of Research of the National Institute of Standards and Technology provides five tables of recommended fluences (dosages) for 1 to 5 log reduction of spores, bacteria, protozoa, viruses, and algae and other large microorganisms. Some of these include opportunistic pathogens such as Legionella pneumophila, Salmonella, Mycobacteria, and the cyanobacterium Microcystis aeruginosa which can produce geosmin, MIB, and some cyanotoxins (including the regulated MC-LR). The paper is the most complete source of such data that I am aware of and is open access.

For comparative purposes the fluence/dose applied for Cryptosporidium oocysts in Canada is typically 20 to 40 mJ/cm². The bacteria/cyanobacteria listed above are generally easily inactivated at these doses.

Bill

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Sensitivity of Bacteria, Protozoa, Viruses, and Other Microorganisms to Ultraviolet Radiation

Mahsa Masjoudi, Madjid Mohseni, and James R. Bolton

Journal of Research of the National Institute of Standards and Technology Volume 126, Article No. 126021 (2021) https://doi.org/10.6028/jres.126.021

https://nvlpubs.nist.gov/nistpubs/jres/126/jres.126.021.pdf

https://www.nist.gov/nist-research-library/journal-research-nist

Introduction

“This paper represents the third revision of a compilation that goes back to 1999. The original compilation was an internal document of Trojan Technologies [1]. The first revision was published in 2006 [2], and the second revision was published in 2016 [3]. Data from the previous reviews have been included here. In addition, data from the past 5 years (up to March 2021) have been added. Two other reviews of the sensitivity of microorganisms to ultraviolet (UV) radiation have been published elsewhere [4, 5]. Tables A1–A5 (in Appendix A) present, to the best of our knowledge, a summary of all peer-reviewed fluence-response data for UV exposure of various microorganisms that are pathogens, indicators, or organisms encountered in the application, testing of performance, and validation of UV disinfection technologies. The tables reflect the current state of knowledge, but they also include the variation in technique and biological response that currently exists in the absence of standardized protocols (see Refs. 6 and 7). Most of the data are from studies of microorganisms suspended in water; however, there are a few entries for microorganisms on surfaces or in air. Users are encouraged to review the original referenced publication for more details on the experimental protocols before they use the data. The references from which the data were abstracted must be carefully read to understand how the reported fluences were calculated and the assumptions and procedures used in the calculations.”

“Finally, it is noted that in Europe and other parts of the world, the units W m–2 for irradiance or fluence rate and J m–2 for fluence (UV dose) are more commonly used; the conversions are 1 mW cm–2 = 10 W m–2 and 1 mJ cm–2 = 10 J m–2 . The data in the tables are for specific log reductions, where log reduction = 1, 2, 3, 4, and 5 for mean 90%, 99%, 99.9%. 99.99%, and 99.999% reduction, respectively. Log reduction is defined as log₁₀ (N₀/N), where N₀ is the initial viable microorganism count, and N is the final value after UV exposure.”

Hi all…while several studies have reported that viable infectious SARS-CoV-2 virus doesn’t seem to survive wastewater treatment there have not been any studies that I am aware of which have assessed survival of the virus itself and its RNA in freshwater. A recently published study found that persistence of viable SARS-CoV-2 was temperature dependent, remaining infectious for significantly longer periods of time in freshwater at 4°C than at 20°C. This is consistent with other viruses. The T₉₀ for infectious SARS-CoV-2 in river water was 2.3 days and 3.8 days at 20°C and 4°C, respectively, but the viral RNA was much more stable (remained detectable for the 20 day duration of the experiment). The authors acknowledged that, unsurprisingly, “indigenous microbial populations” play an important role in RNA stability. Several other potential surrogates for SARS-CoV-2 RNA were not useful.

Bill

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Decay of infectious SARS-CoV-2 and surrogates in aquatic environments

https://doi.org/10.1016/j.watres.2021.117090

Laura Sala-Comorera, Liam J. Reynolds, Niamh A. Martin, John J. O’Sullivan, Wim G. Meijer, Nicola F. Fletcher

Water Research Volume 201, 1 August 2021, 11709

 Abstract

“The introduction of SARS-CoV-2 containing human stool and sewage into water bodies may raise public health concerns. However, assessment of public health risks by faecally contaminated water is limited by a lack of knowledge regarding the persistence of infectious SARS-CoV-2 in water. In the present study the decay rates of and SARS-CoV-2 RNA were determined in river and seawater at 4 and 20°C. These decay rates were compared to S. typhimurium bacteriophage MS2 and pepper mild mottle virus (PMMoV). Persistence of viable SARS-CoV-2 was temperature dependent, remaining infectious for significantly longer periods of time in both freshwater and seawater at 4°C than at 20°C. T₉₀ for infectious SARS-CoV-2 in river water was 2.3 days and 3.8 days at 20°C and 4°C, respectively. The T₉₀ values were 1.1 days and 2.2 days in seawater at 20°C and 4°C, respectively. In contrast to the rapid inactivation of infectious SARS-CoV-2 in river and sea water, viral RNA was relatively stable. The RNA decay rates were increased in non-sterilised river and seawater, presumably due to the presence of microbiota. The decay rates of infectious MS2, MS2 RNA and PMMoV RNA differed significantly from the decay rate of SARS-CoV-2 RNA, suggesting that their use as surrogate markers for the persistence of SARS-CoV-2 in the environment is limited.”

Hi all…following up from my last email dealing with SARS-CoV-2 virus in river water, a survey of the prevalence and levels of enteric viruses in untreated groundwater of 62 private wells used for drinking and/or agricultural practices in rural Alberta using the qPCR panel assay, integrated cell culture with qPCR, and cell culture, has been published in the journal Water Research. Seven viruses were assessed including adenovirus, rotavirus, norovirus, astrovirus, sapovirus, reovirus, and JC virus. The authors report that the most frequently detected virus was adenovirus (48.9%, 22/45) followed by rotavirus (44.4%, 20/45), reovirus (20%, 9/45), JC virus (6.7%, 3/45) and norovirus (6.7%, 3/45). They conclude that “conventional fecal bacterial indicators (coliform and/or E. coli) were not a representative marker for viral contamination in groundwater wells in rural Alberta.”

One of this study’s substantial strengths is the use of 3 different detection methods rather than relying on a single method. The comparison with coliforms and E. coli is also useful. As with most (if not all) enteric viruses these can be inactivated with free chlorine and/or UV at typical drinking water treatment doses. There are also some interesting statistics on groundwater and wells in the Introduction.

I had not heard of the JC virus prior to reading this article. The AACC defines it as “John Cunningham or JC virus (JCV)…a non-enveloped, double-stranded DNA virus that, following primary infection, undergoes latency in tonsillar tissue, renal tubular cells, bone marrow, or the brain. Seroprevalence studies suggest that >50% of adults over the age of 20 have been exposed to it (Ann Neurol 2015;77:560–70).”

This paper has some similarities with a 2020 paper entitled “Viral, bacterial, and protozoan pathogens and fecal markers in wells supplying groundwater to public water systems in Minnesota, USA” for those with an interest in the topic.

Bill__________________________________________________________________________

The Prevalence and Levels of Enteric Viruses in Groundwater of Private wells in Rural Alberta, Canada

Xiaoli Pang , Tiejun Gao , Yuanyuan Qiu , Niamh Caffrey , Jessica Popadynetz , John Younger , Bonita E. Lee , Norman Neumann , Sylvia Checkley

Water Research Available online 10 July 2021, 117425–The paper is Open access and currently in pre-proof form.

Highlights:

• Studying virus contamination of water in 62 private wells through serial sampling
• Prevalence of enteric viruses was very low and sporadic in groundwater
• Adenovirus and rotavirus were detected most frequently among others
• Well setting for different uses was not related to presence of the viruses
• Analyzing effect of well characteristics on occurrence of viruses in groundwater

Abstract

“The prevalence and levels of enteric viruses in untreated groundwater of private wells used for drinking and/or agricultural practices in rural Alberta were studied using the qPCR panel assay, integrated cell culture with qPCR and cell culture in the volume of 500 liters per sample through serial sampling. Seven viruses were assessed including adenovirus, rotavirus, norovirus, astrovirus, sapovirus, reovirus and JC virus. Five viruses were detected with an overall positive detection rate of 6.33 % (45 of 711 samples). The most frequently detected virus was adenovirus (48.9%, 22/45) followed by rotavirus (44.4%, 20/45), reovirus (20%, 9/45), JC virus (6.7%, 3/45) and norovirus (6.7%, 3/45). There was no significant difference in the positive detection rates, ranging from 1.1% to 3.4% by various well settings used for broiler farms, cow/calf farms, feedlots and rural acreages. Effects of well characteristics (aquifer type, well depth, static level of water, well seal) and well completion lithology on potential viral contamination of groundwater of private wells were also analyzed upon available data. The findings demonstrate that occurrence of enteric viruses is low and viral contamination is sporadic in groundwater of private wells in rural Alberta. Conventional fecal bacterial indicators (coliform and/or E. coli) were not a representative marker for viral contamination in groundwater wells in rural Alberta.”

Hi all…an interesting SARS-CoV-2 study was recently published in the journal Water Research. While most research has focused on wastewater and typically monitoring for SARS-CoV-2 RNA, this study examined virus viability and compared raw domestic wastewater with river water. While there are a number of interesting observations, the one that caught my eye, at least from a drinking water perspective, was the finding that “Remarkable increases in SARS-CoV-2 persistence were observed in assays at 4°C, which showed T₉₀ values of 7.7 and 5.5 days, and T₉₉ values of 18.7 and 17.5 days for RW and WW, respectively.”

For the most part, the virus is pretty well removed during wastewater treatment, and should be well removed during treatment in surface water treatment plants (and any systems that at least chlorinate continuously and efficiently). Perhaps this has implications for groundwater or infiltration wells (cottages, very small systems, etc.) when there are discharges to the environment other than from wastewater treatment plants?

Bill

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Viability of SARS-CoV-2 in river water and wastewater at different temperatures and solids content

Leonardo Camilo de Oliveira, Andrés Felipe Torres-Franco, Bruna Coelho Lopes, Beatriz Senra Álvares da Silva Santos, Erica Azevedo Costa, Michelle S. Costa, Marcus Tulius P. Reis, Marília C. Melo, Rodrigo Bicalho Polizzi, Mauro Martins Teixeira, César Rossas Mota

Water Research Volume 195, 1 May 2021, 117002

Abstract

“COVID-19 patients can excrete viable SARS-CoV-2 virus via urine and faeces, which has raised concerns over the possibility of COVID-19 transmission via aerosolized contaminated water or via the faecal-oral route. These concerns are especially exacerbated in many low- and middle-income countries, where untreated sewage is frequently discharged to surface waters. SARS-CoV-2 RNA has been detected in river water (RW) and raw wastewater (WW) samples. However, little is known about SARS-CoV-2 viability in these environmental matrices. Determining the persistence of SARS-CoV-2 in water under different environmental conditions is of great importance for basic assumptions in quantitative microbial risk assessment (QMRA). In this study, the persistence of SARS-CoV-2 was assessed using plaque assays following spiking of RW and WW samples with infectious SARS-CoV-2 that was previously isolated from a COVID-19 patient. These assays were carried out on autoclaved RW and WW samples, filtered (0.22 µm) and unfiltered, at 4°C and 24°C. Linear and nonlinear regression models were adjusted to the data. The Weibull regression model achieved the lowest root mean square error (RMSE) and was hence chosen to estimate T₉₀ and T₉₉ (time required for 1 log and 2 log reductions, respectively). SARS-CoV-2 remained viable longer in filtered compared with unfiltered samples. RW and WW showed T₉₀ values of 1.9 and 1.2 day and T₉₉ values of 6.4 and 4.0 days, respectively. When samples were filtered through 0.22 µm pore size membranes, T₉₀ values increased to 3.3 and 1.5 days, and T₉₉ increased to 8.5 and 4.5 days, for RW and WW samples, respectively. Remarkable increases in SARS-CoV-2 persistence were observed in assays at 4°C, which showed T₉₀ values of 7.7 and 5.5 days, and T₉₉ values of 18.7 and 17.5 days for RW and WW, respectively. These results highlight the variability of SARS-CoV-2 persistence in water and wastewater matrices and can be highly relevant to efforts aimed at quantifying water-related risks, which could be valuable for understanding and controlling the pandemic.”

Hi all…following up from my recent email on the release of USEPA UCMR 4 data, a paper has just been published which compares satellite imagery to cyanobacterial data and observations collected as part of the UCMR 4. It presents the first large-scale assessment of cyanobacterial frequency and abundance of surface water near drinking water intakes across the United States. The authors report that “overall agreement between satellite imagery and UCMR 4 qualitative responses was 94%.” While the highlights summarize key findings, this paper requires a bit of reading to fully contextualize them. The lack of historical (and even current) satellite imagery, as well as sufficiently large and documented data sets, may limit its applicability in public water systems outside of the USA. And while five source waters demonstrated a sustained short-term trend it was indicated that a decade of satellite imagery would be required for observed environmental trends to outweigh variability in the data.

Highlights

 “Satellite-derived cyanobacteria and qualitative sampler responses had 94% agreement

• 685 drinking water sources are observable with 300-m satellite imagery
• 2019 temporal frequency of blooms averaged 2% across source waters, peaking at 100%
• Effect size of 10 years needed for observed trends to outweigh residual variability
• Only 5 source waters have sufficient data for a sustained trend from 2016-2020”

Bill

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Assessing cyanobacterial frequency and abundance at surface waters near drinking water intakes across the United States

Megan M. Coffer, Blake A. Schaeffer, Katherine Foreman, Alex Porteous, Keith A. Loftin, Richard P. Stumpf, P. Jeremy Werdell, Erin Urquhart, Ryan J. Albert, and John A. Darling

Water Research

Available online 24 June 2021, 117377 In Press, Journal Pre-proof    https://www.sciencedirect.com/science/article/abs/pii/S0043135421005753?via%3Dihub

Abstract

“This study presents the first large-scale assessment of cyanobacterial frequency and abundance of surface water near drinking water intakes across the United States. Public water systems serve drinking water to nearly 90% of the United States population. Cyanobacteria and their toxins may degrade the quality of finished drinking water and can lead to negative health consequences. Satellite imagery can serve as a cost-effective and consistent monitoring technique for surface cyanobacterial blooms in source waters and can provide drinking water treatment operators information for managing their systems. This study uses satellite imagery from the European Space Agency’s Ocean and Land Colour Instrument (OLCI) spanning June 2016 through April 2020. At 300-m spatial resolution, OLCI imagery can be used to monitor cyanobacteria in 685 drinking water sources across 285 lakes in 44 states, referred to here as resolvable drinking water sources. First, a subset of satellite data was compared to a subset of responses (n = 84) submitted as part of the U.S. Environmental Protection Agency’s fourth Unregulated Contaminant Monitoring Rule (UCMR 4). These UCMR 4 qualitative responses included visual observations of algal bloom presence and absence near drinking water intakes from March 2018 through November 2019. Overall agreement between satellite imagery and UCMR 4 qualitative responses was 94% with a Kappa coefficient of 0.70. Next, temporal frequency of cyanobacterial blooms at all resolvable drinking water sources was assessed. In 2019, bloom frequency averaged 2% and peaked at 100%, where 100% indicated a bloom was always present at the source waters when satellite imagery was available. Monthly cyanobacterial abundances were used to assess short-term trends across all resolvable drinking water sources and effect size was computed to provide insight on the number of years of data that must be obtained to increase confidence in an observed change. Generally, 2016-2020 was an insufficient time period for confidently observing changes at these source waters; on average, a decade of satellite imagery would be required for observed environmental trends to outweigh variability in the data. However, five source waters did demonstrate a sustained short-term trend, with one increasing in cyanobacterial abundance from June 2016 to April 2020 and four decreasing.”