Pure Water Occasional, February 18, 2020 |
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Trees Work Like Straws
Research at Washington State University indicates that the effects of wildfires last much longer than we have always assumed:
"Trees work like straws, pulling water up out of the ground," said Ryan Niemeyer of WSU's Center for Sustaining Agriculture and Natural Resources. "When you remove them, the water has to go somewhere. Flooding is common after a wildfire, as is elevated stream flow in subsequent summers. But seeing that the effect lasts for up to 40 years is a little surprising and certainly a new finding."
The World Resouces Institute named Israel, Lebanon, Qatar, and Iran as the countries that top the world's water crisis list.
Research reported in Science Advances shows that oceans are not only getting warmer and windier, but the speed of currents, not only on the surface but as deep as 6,500 feet, have steadily increased since 1990. Rate of increase is about 5% per decade.
Mexico's federal government dispatched National Guard officers to protect La Boquilla dam in northern Mexico in a clash with hundreds of farmers in a fight for possession of the dam's control room. This is part of a long-standing dispute over water that results from a 1944 water treaty between the US and Mexico. In a nutshell, Mexico owes the US water and President Lopez Obrador wants water to repay the debt, but area farmers are refusing to give it up. Details from US News.
A phone-distracted driver hit a fire hydrant near Harvard's Bromfield School causing a deluge that closed schools and local businesses, led to boil water alerts, and virtually drained the community's 275,000 gallon water tower. The hydrant is at one of the lowest points in the tower's service area and is fed by a 12-inch main, so water flow was fast and furious. Harvard Press.
Secrecy is one of the main obstacles preventing recycling and reuse of the oceans of fracking water that are disposed of each day. "Researchers have to figure out how to remvoe the toxic substances in produced water, such as benzene and iron. But first, they'll have to pierce the veil of secrecy around its contents. Each oil and gas operator uses a different fracking cocktail, whose ingredients are kept under wraps. If researchers don't know what chemicals are in fracking water, they won't be able to determine how to remove them and set safety standards." For a look at the massive water industry that has been spawned by fracking see this article in the High Country News.
As public concern about plastic pollution rises, consumers are reaching for canvas bags, metal straws, and reusable water bottles. But while individuals fret over eliminating plastic straws from their lives, the fossil fuel and petrochemical industries are pouring billions of dollars into new plants designed to make and market millions more tons of plastic than they now pum pout. Companies like ExxonMobil, Shell, and Saudi Aramco are ramping up output plastic - which is made from oil and gas and their byproducts - to hedge against the possibility that a serious global response to climate change might reduce demand for their fuels.
Petrochemicals, the category that includes plastic, now account for 14 percent of oil use, and are expected to drive half of oil demand growth between now and 2050, the International Energy Agency says. The World Economic Forum predicts plastic production will double in the next 20 years. Full article.
Significant research reported by ACS Publications addressed the problem of increased lead in tap water when suppliers switch disinfectants from free chlorine to monochloramine. Using synthetic water and new lead pipe, researchers concluded that switching disinfectants without pre-treatment of pipes raised tap water lead levels from 5 ppb to as high as 150 ppb. (Allowable limit is 15 ppb.) When pipes were treated with a phosphate injection, however, prior to and during the change to monochloramine, lead levels remained below the allowable level. Full article.
The Guardian reports that the pace of sea level rise accelerated at nearly all measurement stations along the U.S. coastline in 2019, with scientists warning some of the bleakest scenarios are steadily becoming more likely. The highest rate of sea level rise was recorded along the Gulf of Mexico shoreline, with Grand Isle, LA experiencing a nearly 8 millimeter annual increase, more than double the global average. The Texas locations of Galveston and Rockport had the next largest increases.
Top Four Fatbergs in the UK Identified
The term “fatberg” is slowly but surely making its way into the vocabulary of the general public.
Defined as “a large mass of fat and solid waste that collects in a sewer system," fatberg was even announced as one of 533 new words to be added to the Merriam-Webster dictionary.
Water utilities can spend millions every year clearing blockages that result from homeowners and businesses pouring fats, oils and greases (known in the industry as FOG) down drains. It’s estimated that there are over 300,000 sewer blockages across the UK annually.
Probably you have been waiting for a ranking of leading fatburgs. Beginning with Whitechapel, London's beloved Fatty McFatberg, the undisputed King of Fatbergs, an Aquatech article discusses the UK's four greatest fatbergs. This is an article you don't want to miss.
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Beginning with this issue, the Occasional will include a brief FAQ section in each issue, using actual current questions that we get in Pure Water Products' email and phone interactions with customers. We'll paraphrase both the question and answer to remove personal information and make the answer more useful to a general audience. Here's the first:
FAQ
Will my RO unit remove PFAS?
Question: A long-time customer who lives on the Texas/Mexican border wrote explaining that although there is a military base near his home, his city has not yet tested for PFAS contamination in its water supply. He owns one of our Economy RO units and asks if it will protect him from PFAS.
Answer: While it is obviously impossible to assess the capability of a single RO unit to treat an unknown amount of a contaminant that may or may not be in the water, reverse osmosis has been consistently shown to be a reliable remover of PFAS. If the RO unit is well maintained and is showing good TDS readings, there is no reason to believe that it would not make a significant reduction in PFAS. In recently reported research at Duke University, every home reverse osmosis unit tested removed PFAS successfully. If your home unit is serviced regularly and the TDS performance is good, don't worry about PFAS.
We sent a link to an article for the Pure Water Gazette website which addresses the issue of residential treatment of PFAS. See article reprinted in part below.
Can small whole house filter cartridges effectively remove chloramine?
Question: How can a cartridge filter remove chloramine as effectively as a very large backwashing filter?
Answer: The most effective cartridge filters use powdered carbon which has much greater surface area per size than the coffee-ground-sized granules of 30 and 40 mesh carbon used in tank style filters. Powdered carbon has much more surface area then standard granular carbon, whether it is fused into a carbon block or contained in one of the newer "radial flow" powdered filter designs. Removing chloramines with cartridges follows a whole different set of rules that hasn't been fully studied or understood. See the comments on carbon block filters in this article. (Excerpts of the article are reprinted below.)
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Not All In-Home Drinking Water Filters Completely Remove Toxic PFAS
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Research by Duke and NC State scientists finds most filters are only partially effective at removing PFAS. A few, if not properly maintained, can even make the situation worse.
Pure Water Gazette introductory note. We’re reprinting WaterOnline’s reporting on Duke University research that appeared recently. We take issue with the “glass is half empty” title, which more appropriately should be “All Home Reverse Osmosis Units Tested In Duke Research Removed PFAS Handily.” Are we supposed to be surprised and disappointed that a $35 end-of-faucet filter from Walmart failed to remove tiny amounts of perfluoroalkyl sulfonic acids, perfluoroalkyl carboxylic acids, and per- and poly-fluoroalkyl ether acids from tap water? We take issue as well with the implication that home reverse osmosis units are luxury items beyond the reach of homeowners because of cost. A home appliance that costs less than a smart phone and provides years of superb drinking water? We added the image below from the original Duke research because it summarizes the findings: small carbon filters were partially effective, double undersink filters were very effective (though researchers could not explain why), and undersink reverse osmosis units of various brands, states of upkeep and age were uniformly effective.
The water filter on your refrigerator door, the pitcher-style filter you keep inside the fridge and the whole-house filtration system you installed last year may function differently and have vastly different price tags, but they have one thing in common.
They may not remove all of the drinking water contaminants you’re most concerned about.
A new study by scientists at Duke University and North Carolina State University finds that – while using any filter is better than using none – many household filters are only partially effective at removing toxic perfluoroalkyl substances, commonly known as PFAS, from drinking water. A few, if not properly maintained, can even make the situation worse.
“We tested 76 point-of-use filters and 13 point-of-entry or whole-house systems and found their effectiveness varied widely,” said Heather Stapleton, the Dan and Bunny Gabel Associate Professor of Environmental Health at Duke’s Nicholas School of the Environment.
“All of the under-sink reverse osmosis and two-stage filters achieved near-complete removal of the PFAS chemicals we were testing for,” Stapleton said. “In contrast, the effectiveness of activated-carbon filters used in many pitcher, countertop, refrigerator and faucet-mounted styles was inconsistent and unpredictable. The whole-house systems were also widely variable and in some cases actually increased PFAS levels in the water.”
“Home filters are really only a stopgap,” said Detlef Knappe, the S. James Ellen Distinguished Professor of Civil, Construction and Environmental Engineering at NC State, whose lab teamed with Stapleton’s to conduct the study. “The real goal should be control of PFAS contaminants at their source.”
PFAS have come under scrutiny in recent years due to their potential health impacts and widespread presence in the environment, especially drinking water. Exposure to the chemicals, used widely in fire-fighting foams and stain- and water-repellants, is associated with various cancers, low birth weight in babies, thyroid disease, impaired immune function and other health disorders. Mothers and young children may be most vulnerable to the chemicals, which can affect reproductive and developmental health.
Some scientists call PFAS “forever chemicals” because they persist in the environment indefinitely and accumulate in the human body. They are now nearly ubiquitous in human blood serum samples, Stapleton noted.
The researchers published their peer-reviewed findings Feb. 5 [2020] in Environmental Science & Technology Letters. It’s the first study to examine the PFAS-removal efficiencies of point-of-use filters in a residential setting.
They analyzed filtered water samples from homes in Chatham, Orange, Durham and Wake counties in central North Carolina and New Hanover and Brunswick counties in southeastern N.C. Samples were tested for a suite of PFAS contaminants, including three perfluoroalkal sulfonic acids (PFSAs), seven perfluoroalkyl carboxylic acids (PFCAs) and six per- and poly-fluoroalkyl ether acids (PFEAs). GenX, which has been found in high levels in water in the Wilmington area of southeastern N.C., was among the PFEAs for which they tested.
Key takeaways include:
- Reverse osmosis filters and two-stage filters reduced PFAS levels, including GenX, by 94% or more in water, though the small number of two-stage filters tested necessitates further testing to determine why they performed so well.
- Activated-carbon filters removed 73% of PFAS contaminants, on average, but results varied greatly. In some cases, the chemicals were completely removed; in other cases they were not reduced at all. Researchers saw no clear trends between removal efficiency and filter brand, age or source water chemical levels. Changing out filters regularly is probably a very good idea, nonetheless, researchers said.
- The PFAS-removal efficiency of whole-house systems using activated carbon filters varied widely. In four of the six systems tested, PFSA and PFCA levels actually increased after filtration. Because the systems remove disinfectants used in city water treatment, they can also leave home pipes susceptible to bacterial growth.
“The under-sink reverse osmosis filter is the most efficient system for removing both the PFAS contaminants prevalent in central N.C. and the PFEAs, including GenX, found in Wilmington,” Knappe said. “Unfortunately, they also cost much more than other point-of-use filters. This raises concerns about environmental justice, since PFAS pollution affects more households that struggle financially than those that do not struggle.”
Nick Herkert, a postdoctoral associate in Stapleton’s lab, was lead author on the study. John Merrill of NC State and Cara Peters, David Bollinger, Sharon Zhang, Kate Hoffman and Lee Ferguson of Duke were co-authors. Funding came from the N.C. Policy Collaboratory through the N.C. PFAS Testing Network and from the Wallace Genetic Foundation. Duke and NC State scientists finds most filters are only partially effective at removing PFAS. A few, if not properly maintained, can even make the situation worse.
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Chloramines in Drinking Water
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The EPA’s webpage on chloramines begins like this:
Chloramines are disinfectants used to treat drinking water. Chloramines are most commonly formed when ammonia is added to chlorine to treat drinking water. The typical purpose of chloramines is to provide longer-lasting water treatment as the water moves through pipes to consumers. This type of disinfection is known as secondary disinfection. Chloramines have been used by water utilities for almost 90 years, and their use is closely regulated. More than one in five Americans uses drinking water treated with chloramines. Water that contains chloramines and meets EPA regulatory standards is safe to use for drinking, cooking, bathing and other household uses.
In spite of the EPA's assurances of safety, the use of chloramine in city water supplies has provoked continual controversy.
Treatment for Chloramines: Removing Chloramines from Water
Reduction of chloramines from city water is a commonly misunderstood issue. For those unfamiliar with the details of water treatment, there is often an expectation that there is a “filter” for every contaminant that specifically identifies that contaminant and, as if by magic, “takes it out.” A frequent question is “How much does it take out?” It isn’t quite as simple as that, especially with “problem contaminants” like chloramines.
Here is an excerpt from technical writer David Bauman. This is from a Water Technology article on chloramines. By way of explanation, the “catalytic carbon” Mr. Bauman refers to is commonly known by its most common brand name, Centaur carbon. Other brands of catalytics are now on the market, however.
Removal possibilities Chloramines should not be confused with chlorine. Chloramines cannot be removed by passing water through the same activated carbon filters used for chlorine removal because these filters are too small at their designed flow rates.
The following are four types of water treatment technologies that can be used to remove chloramines at the point of use:
Catalytic Carbon. This has a surface structure that has been altered from standard activated carbon, enabling it to remove chloramines, providing close attention is given to contact time, mesh size of the carbon and influent temperature. Theoretically, the carbon decomposes chloramine into traces of nitrogen gas, ammonia gas and chloride. If these reactions are not allowed to be completed, surface oxygen groups form that can foul or exhaust the carbon.
With a 2-mg/L chloramine influent level, enhanced catalytic carbon can produce product water that maintains a <0.1-mg/L residual (required for dialysis). Manufacturer’s data on this type of carbon refer to flow rates ranging from 30 seconds to two minutes of empty bed contact time (EBCT). This converts to between about 3.5 gallons per minute per cubic feet (gpm/ft3) and 15 gpm/ft3.
This does not mean that 15 gpm/ft3 is acceptable. For example, although the product water may be acceptable at this rate, the pressure loss may be prohibitive and the length of run before chloramine breakthrough may be reduced from 88,000 gallons to 11,000 gallons. Designers of dialysis water treatment systems use 10 minutes of EBCT. This contact time was established prior to the development of catalytic carbon, but because of the specifications required by the US Food and Drug Administration, which regulates dialysis water treatment equipment as medical devices, in most cases this has not changed. According to catalytic carbon data, this time could be reduced to about three minutes.
Decreasing the mesh size of the carbon can more than double the gallon throughput, although it may also create more pressure loss. An increase in temperature from about 58 degrees F to 72 F also can more than double the gallon throughput.
The word catalytic normally means enabling a reaction without entering into the reaction. This would imply that the catalyst would never change or become depleted. In reality this is probably not true; other adsorbable and ionic species in the water adsorb onto the carbon and eventually mask the catalytic sites. The more catalytic sites there are on the carbon, the longer its useful life.
In addition, friction physically depletes the material; other foulants, such as iron, can foul it; and high pressure differential can crush it.
Standard activated carbon.Used for chloramine removal long before catalytic carbon became available, standard activated carbon requires a very long contact time, which means a large volume of carbon is needed.
Everything attributed to catalytic carbon applies to standard carbon, although to a lesser degree. All activated carbon has some catalytic capability, but standard carbons of all common basic materials have a relatively low activity for chloramine removal. For thorough removal, up to four times the contact time of catalytic carbon may be required. Substantial increases in percent removal and length of run before chloramine breakthrough can be achieved with smaller mesh carbon. Some systems have been designed that precondition the carbon by exposure to general use or to chlorine.
Carbon cartridge filters have been tested for chloramine removal, but since no national testing standard has been established, no claims are being made. Some cartridges have a real advantage: fine or powdered carbons, such as those used in cartridges, are excellent chloramine removal media in spite of not being made from catalytic material.
They can render the discussions regarding catalytic vs. standard carbon moot.
Ascorbic acid. Used for dialysis before the development of catalytic carbon, this acid acted – as would other reducing agents – by reducing monochloramine to chloride and ammonia. However, this acid is not advised for drinking water applications and is no longer used for dialysis treatment.
The practical realities one is left with from Mr. Bauman’s excellent summation of removal strategies are that:
1. Except in a controlled industrial setting, it is next to impossible to predict the lifespan or the exact reduction percentage of a water filter used for chloramines.
2. Such variables as water temperature, flow rate, mesh size of the medium (in the case of carbon), and other contaminants in the water greatly affect the effectiveness and the longevity of the filter.
3. The often-used blanket statement that “reverse osmosis does not remove chloramines” is technically true but realistically false. While the reverse osmosis membrane itself does not remove chloramines, every respectable RO unit is equipped with two or more high quality carbon filters. Pre-filters, the filters that process the water before the membrane, receive water at a very slow rate of flow and therefore work under excellent conditions for chloramine reduction. The use of the high quality cartridges described by Mr. Bauman actually should provide superb chloramine reduction in an undersink RO unit, yet the “reverse osmosis does not remove chloramines” myth is perpetuated by sellers of non-RO products.
4. If you are thinking of purchasing a “whole house” chloramine filter, your choice in sizing should be made considering the life expextancy of the carbon. Mr. Bauman’s figures show that the carbon’s lifespan could be reduced to as little as 1/8 by undersizing.
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How pH Affects Well Sanitation
by Pure Water Annie
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Pure Water Gazette Technical Writer, Pure Water Annie, clears the water on the troublesome issue of "shocking" a water well.
When a residential water well is “shocked” with chlorine to rid it of bacterial contaminants, it is usually assumed that just dumping some bleach down the well will do the job. This article will show you why quantity matters when it comes to adding chlorine to a well and why it is important to follow one of the many good instruction sheets on well sanitation or to use a chlorine product especially designed for the task.
When chlorine is added to water, it produces hypochlorous acid (HOCl) and hychlorite ions (OCl-). Hypochlorous acid is by far the most effective and quickest chlorine ingredient for sanitizing. It is 80 times as fast and efficient as OCl-.
What is often not considered is that hypochlorous acid is produced most abundantly at a relatively low pH. Between pH 5 and 7, chlorine as hypochlorous acid acts mainly as a sanitizer–what you need for killing bacteria. As the pH goes up and the water becomes more alkaline, chlorine begins to act more as an oxidizer (what you need for precipitating iron or manganese).
The problem is that when you add calcium hypochlorite (chlorine pellets) or sodium hypochlorite (liquid bleach), you also raise the pH of the water. As the pH goes up, the chlorine loses its sanitizing power. At pH 9, the chlorine is mainly an oxidizer and will not kill bacteria efficiently.
In a word, over-chlorinating raises the pH to the point where chlorine does not kill bacteria.
HOCl predominates between pH levels of about 4 and 7. After 7 it drops off rapidly.
Although acids such as muriatic acid or sodium bisulfate are sometimes used to keep pH low and thus enhance the sanitizing power of chlorine, for homeowners whose wells are in the normal pH range it makes most sense to simply avoid over-chlorinating by following the dosage and procedures put forth by experts in the field.
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Is Our Whole Understanding of Water Contamination a Bogus Science?
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The following article about the power of tiny amounts first appeared in the Pure Water Gazette in 2013 but it seems more appropriate today than ever. We're now concerned about water contaminants measured in parts per trillion and we are learning that lead, which used to be considered OK up to 50 parts per billion, is now unacceptable at 20. Will we eventually discover that 1 ppb of lead is worst of all?
Baby mice exposed in the womb to low doses – but not high doses – of bisphenol A were fatter and had metabolic changes linked to obesity and diabetes, according to a new study published today. Building on previous studies that link the hormone-altering chemical to changes in body weight and glucose tolerance, the new research fuels an ongoing controversy over whether federal testing of chemicals is adequate to protect people from low doses. “What’s scary is that we found effects at levels that the government not only says is safe, but that they don’t bother to test,” said Frederick vom Saal, a University of Missouri, Columbia, professor and senior author of the study. Many of the effects were reported in the mice fed daily doses – just during pregnancy – that were one-tenth of the amount that the U.S. Environmental Protection Agency says is safe for daily exposure throughout life. Used in polycarbonate plastics, canned food liners and some thermal receipts, BPA is found in almost everyone’s body. Some earlier studies have linked it to obesity and diabetes in people.
The report goes on to explain that current water regulatory practices are carried out under the assumption that high doses are more potent than low doses, so if a chemical does not prove harmful at a dosage of 5 parts per billion, there is no reason to test it at a concentration of 1 part per billion.
Modern Science, like all belief systems, holds certain principles to be sacred and beyond challenge. One of these is the idea that when a substance is present in a large amount it is more powerful than it would be in a smaller amount. In other words, more is always more, and less is always less. On the occasions when less seems to be more, as with the current BPA issue, the scientific establishment simply dismisses the finding as heresy. If the heretic refuses to recant, he is burned at the stake. Witness the case of the French scientist Jacques Benveniste, who in 1988 challenged the “more is always more” commandment and was excommunicated by Orthodox Science. Benveniste’s sin against scientific orthodoxy was to publish experiments demonstrating that water has the ability to remember substances whose physical presence has been entirely removed from it. (See The Lost Genitals of Uranus, or How Is an Elephant like a Glass of Water?)
Less is more, of course, is not a revolutionary idea, although orthodox Science treats it like one. Less is more is a cornerstone principle of the science of Homeopathy, which calls it the Law of Infinitesimals. There are countless well documented exceptions to the more is more dogma. The truth seems to be that more is most often more, but sometimes less is more.
Low doses of BPA spurred weight gain and other metabolic changes in baby mice. Of the doses fed to the pregnant mice – 5, 50, 500, 5,000 and 50,000 micrograms per kilogram – 500 caused the most metabolic changes. The number of fat cells doubled at the 500 dose. No effects were seen at doses higher than 5,000.
The entire belief system on which modern water treatment practices are based depends on upholding the principal that more is always more. Without it, there would be chaos. How can we regulate water contaminants if we have to contend with the absurd notion that reducing their quantity may actually be making them more potent threats to human health? And even if a contaminant is removed to a non-detectable level, how can we be sure that humans are not being affected by water’s memory of the contaminant?
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Thanks for reading and be sure to check out the next Occasional!
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