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 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.”
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.
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.
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 Prevalence and Levels of Enteric Viruses in Groundwater of Private wells in Rural Alberta, Canada
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.
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.”
Assessing cyanobacterial frequency and abundance at surface waters near drinking water intakes across the United States
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.
Health Canada continues to be active with requests for public comment on proposed drinking water guidelines and guidance documents. At present, there are 4 of these with due dates for comments in the next three months. I’ve listed them below along with the due dates for comments. Each is linked to the Health Canada website with PDF format documents which can be downloaded.
The study estimated the disease burden attributable to nine enteric pathogens, unspecified pathogens leading to gastroenteritis, and three opportunistic pathogens leading primarily to respiratory illness.