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Removing Toxic Fluorinated Chemicals From Your Home’s Tap Water
By EWG Science Team
The family of fluorinated compounds known as PFAS chemicals includes more than 4,700 chemicals—some linked to cancer, thyroid disease, weakened immunity and developmental defects, and others whose health effects are unknown. One thing's for sure: You don't want them in your body.
Drinking water is one of the most common sources of exposure. PFAS chemicals could contaminate the drinking water for 110 million Americans nationwide. The Environmental Working Groups's (EWG) interactive map shows areas of known contamination. If you know or suspect these chemicals are in your tap water, the best way to protect yourself is by installing an in-home water filter. But which kind?
Based on information from state health agencies, testing labs, scientific researchers and water filter companies, the most effective choice for in-home treatment of PFAS-tainted tap water is a reverse osmosis filter, followed by an activated carbon filter—a slightly lower-cost option.
But many questions remain unanswered. More research is urgently needed to better understand how to ensure removal of the many types of PFAS compounds. To help with your choice, below are details of what is currently known.
Disclaimer: EWG is not recommending any specific brand of filter and cannot guarantee that a filter's performance will match the results reported below.
States Leading Response to PFAS Contamination Crisis
The U.S. Environmental Protection Agency (EPA) has set a health advisory level for the two most-studied PFAS compounds in drinking water—PFOA, formerly used to make DuPont's Teflon, and PFOS, formerly an ingredient in 3M's Scotchgard. The advisory level is 70 parts per trillion, or ppt, for the two chemicals combined. But the best and most current scientific research says that's much too high, and the EPA's advisory level is not legally enforceable.
That's why some states with extensive PFAS drinking water contamination are taking steps to set more health-protective limits or advisory levels. For example, New Jersey has set a legal limit of 13 ppt for perfluorononanoic acid, or PFNA, and proposed enforceable limits of 14 ppt for PFOA and 13 ppt for both PFOS. Other states such as Washington, Michigan, and North Carolina are conducting additional testing to further evaluate the extent of contamination in drinking water.
Some of these states have issued recommendations for water filters to remove PFOA and PFOS, including:
Guidance and factsheet documents from these states recommend two types of filters for removing PFAS chemicals: activated carbon and reverse osmosis. The states provide information on the pluses and minuses of the two types, and tips on how to maintain them to ensure effective filtering. They also compare the two types of filter installations: "point of use," which are installed under the kitchen sink or in the refrigerator, and "point of entry," which treat the water for the whole house.
In communities with the worst contamination, such as in Minnesota or Michigan, whole-house filtration is often used. It is effective, but expensive in comparison to point-of-use filtration and may not be necessary in most cases. Further, since whole-house systems also remove chlorine, they may introduce additional risks of harmful bacterial growth in plumbing.
Filters Certified for PFAS Chemical Removal
NSF International, a testing and certification company, developed a certification standard for removal of PFOS and PFOA in 2016. The certification requires that the filter reduce these two chemicals only to EPA's health advisory level of 70 ppt. Currently, 71 products from seven manufacturers are certified to meet this standard.
However, drinking water can contain other PFAS chemicals, sometimes at higher levels than PFOS and PFOA. PFOS and PFOA, which are now banned, are called 'long-chain' compounds because they have eight carbon atoms, while the chemicals that have replaced them are called 'short-chain' compounds because they have fewer carbon atoms. While similar, these so-called "next-generation" compounds have different molecular structures, and the effectiveness of filters certified for PFOS and PFOA for removal of replacement PFAS chemicals is unknown.
Filter Testing by State Agencies
In 2007, the Minnesota Department of Health commissioned testing of home water filters to determine their efficacy in removing PFAS. Six activated carbon filters and eight reverse osmosis filter types were tested. The tests determined that four of the six carbon filters and seven of the eight reverse osmosis filters provided sufficient reduction of PFAS chemicals. In field testing, four activated carbon devices and seven reverse osmosis systems, all equipped in tandem with activated carbon filters, removed PFOA, PFOS and PFBA to the detection limit of 50 ppt.
The study noted that for the carbon filters, the effectiveness of removal of PFOA, PFOS and another chemical, PFBA, decreased over operating life in five of the six filters tested in laboratory conditions. That means that users will have to replace the filters on the recommended schedule to ensure effective filtration of PFAS chemicals.
In 2017, Minnesota released the results of a study for a faucet-mounted carbon filter made by PUR. The filter was tested for seven PFAS chemicals typically seen in groundwater in Washington County in Minnesota. The state concluded that this low-cost filter could be used to effectively reduce PFAS contamination. Six of seven contaminants including PFOA and PFOS were removed below the reporting limits of 5 and 10 ppt, respectively, achieved in the 2017 study. In contrast, levels of the shorter chain PFBA were only reduced by 75 percent.
Filter Testing by Academic Institutions
Last year, Knappe told the Star News of Wilmington, N.C. that an under-sink reverse osmosis filter was probably the best choice for home treatment. He said it's not only effective, but its continued effectiveness can be easily verified with an electrical conductivity tester, an inexpensive tool that people can use at home.
Detailed testing results were publicly presented in 2017 for four under-sink reverse osmosis filters and one whole-house activated carbon filter. These filters that were tested for removal of a dozen PFAS chemicals, including both long-chain and short-chain compounds.
Three out of four reverse osmosis filters reduced the long-chain compounds to below 10 ppt, with the other filter reducing them to a slightly higher level. The four reverse osmosis systems also removed between 95 and 99 percent of short-chain compounds.
One whole-house activated charcoal filter from Aquasana was tested. It provided no reduction of PFAS levels. In contrast, an activated carbon filter made by Hydroviv delivered results similar to the reverse osmosis filters.
EWG Contacted Water Filter Companies
EWG surveyed 51 water filter companies to find out about their filters' capabilities to remove PFAS. We heard back from 14 companies, but only four of them verified that their filters remove any PFAS chemicals.
Only Berkey provided EWG with test data for their carbon filters, which reported removal of nine PFAS chemicals, including PFOA and PFOS, all below the detection limit of 2 ppt. However, only 25 gallons of water were filtered, instead of the recommended 6,000 gallons to measure lifetime efficacy. Aqua Systems and Triple Clear stated that removal for their products was only to the EPA advisory levels and Crystal Quest reported that removal was variable.
Reverse Osmosis Filters vs. Activated Carbon Filters
In general, reverse osmosis systems more consistently removed PFAS compared to activated carbon systems.
Most reverse osmosis systems also have the benefit of an additional activated carbon filtration stage included in the system. Reverse osmosis systems remove a wider range of other contaminants from drinking water and their effectiveness can be tested at home using an electrical conductivity meter. But activated carbon filter systems are significantly less expensive than reverse osmosis systems. Carbon filters must be changed on schedule as they will lose their effectiveness over time.
- Check out EWG's interactive PFAS map to see if your drinking water has high levels of PFAS chemicals or if there is a contamination site near your community.
- If you live in an area with contamination, contact your local health department for current information.
- If you have a private well and suspect PFAS contamination, consult your state health department about having your well tested.
- The best bet to filter PFAS chemicals out of your water is an in-home reverse osmosis filter under your sink or at your tap. To ensure that the reverse osmosis filter is working, use an inexpensive conductivity meter. These filter systems remove ions and total dissolved solids in addition to other contaminants, and a low conductivity reading for the filtered water indicates that the filter is overall effective.
- You can also consider an activated carbon filter that will most often provide effective removal. Results have been inconsistent and the filters become less effective with time. If possible, choose a filter that has been tested for PFOS, PFOA and additional PFAS chemicals that may be present in your water.
EcoWatch Daily Newsletter
By Tom Duszynski
How does your body fight off COVID-19?<p>Once a person is exposed the coronavirus, the body starts producing <a href="https://www.mblintl.com/products/what-are-antibodies-mbli/" target="_blank">proteins called antibodies to fight the infection</a>. As these <a href="https://www.statnews.com/2020/03/27/serological-tests-reveal-immune-coronavirus/" target="_blank">antibodies start to successfully contain the virus</a> and keep it from replicating in the body, symptoms usually begin to lessen and you start to feel better. Eventually, if all goes well, your immune system will completely destroy all of the virus in your system. A person who was infected with and survived a virus with no long-term health effects or disabilities has "recovered."</p><p>On average, a person who is infected with SARS-CoV-2 will feel ill for about seven days from the onset of symptoms. Even after symptoms disappear, there still may be small amounts of the virus in a patient's system, and they should stay <a href="https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/steps-when-sick.html" target="_blank">isolated for an additional three days</a> to ensure they have truly <a href="https://health.usnews.com/conditions/articles/coronavirus-recovery-what-to-know" target="_blank">recovered and are no longer infectious</a>.</p>
What about immunity?<p>In general, once you have recovered from a viral infection, your body will keep cells called lymphocytes in your system. These cells "remember" viruses they've previously seen and can react quickly to fight them off again. If you are exposed to a virus you have already had, your antibodies will likely stop the virus before it starts causing symptoms. <a href="https://dx.doi.org/10.5114%2Fceji.2018.77390" target="_blank">You become immune</a>. This is the <a href="https://www.ncbi.nlm.nih.gov/books/NBK27158/" target="_blank">principle behind many vaccines</a>.</p><p>Unfortunately, immunity isn't perfect. For many viruses, like mumps, immunity can wane over time, leaving you <a href="https://www.sciencedaily.com/releases/2016/04/160421145747.htm" target="_blank">susceptible to the virus in the future</a>. This is why you need to get revaccinated – those "booster shots" – occasionally: to prompt your immune system to make more antibodies and memory cells.</p><p>Since this coronavirus is so new, scientists still don't know whether people who recover from COVID-19 are <a href="https://www.cdc.gov/coronavirus/2019-ncov/hcp/faq.html" target="_blank">immune to future infections of the virus</a>. Doctors are finding antibodies in ill and recovered patients, and <a href="https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html" target="_blank">that indicates the development of immunity</a>. But the question remains how long that immunity will last. Other coronaviruses like <a href="https://doi.org/10.1002/jmv.25685" target="_blank">SARS and MERS produce an immune response</a> that will protect a person at least for a short time. I would suspect the same is true of SARS-CoV-2, but the research simply hasn't been done yet to say so definitively.</p>
Why have so few people officially recovered in the US?<p>This is a dangerous virus, so the Centers for Disease Control and Prevention is being extremely careful when deciding what it means to recover from COVID-19. Both medical and testing criteria must be met before a person is <a href="https://www.cdc.gov/coronavirus/2019-ncov/hcp/disposition-in-home-patients.html" target="_blank">officially declared recovered</a>.</p><p>Medically, a person must be fever-free without fever-reducing medications for three consecutive days. They must show an improvement in their other symptoms, including reduced coughing and shortness of breath. And it must be at least seven full days <a href="https://health.usnews.com/conditions/articles/coronavirus-recovery-what-to-know" target="_blank">since the symptoms began</a>.</p><p>In addition to those requirements, the CDC guidelines say that a person must test negative for the coronavirus twice, with the <a href="https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/care-for-someone.html" target="_blank">tests taken at least 24 hours apart</a>.</p><p>Only then, if both the symptom and testing conditions are met, is a person officially considered recovered by the CDC.</p><p>This second testing requirement is likely why there were so few official recovered cases in the U.S. until late March. Initially, there was a <a href="https://www.nytimes.com/2020/03/18/health/coronavirus-test-shortages-face-masks-swabs.html" target="_blank">massive shortage of testing in the U.S.</a> So while many people were certainly recovering over the last few weeks, this could not be officially confirmed. As the country enters the height of the pandemic in the coming weeks, focus is still on <a href="https://www.cdc.gov/coronavirus/2019-nCoV/hcp/clinical-criteria.html" target="_blank">testing those who are infected</a>, not those who have likely recovered.</p><p>Many more people are being tested now that states and private companies have begun <a href="https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/testing-in-us.html" target="_blank">producing and distributing tests</a>. As <a href="https://www.dispatch.com/news/20200406/coronavirus-in-ohio-from-its-rocky-start-testing-for-covid-19-slowly-ramping-up" target="_blank">the number of available tests increases</a> and the pandemic eventually slows in the country, more testing will be available for those who have appeared to recover. As people who have already recovered are tested, the appearance of any new infections will help researchers learn <a href="https://www.statnews.com/2020/03/24/we-need-smart-coronavirus-testing-not-just-more-testing/" target="_blank">how long immunity can be expected to last</a>.</p>
Once a person has recovered, what can they do?<p>Knowing whether or not people are immune to COVID-19 after they recover is going to determine what individuals, communities and society at large can do going forward. If scientists can show that recovered patients are immune to the coronavirus, then a person who has recovered could in theory <a href="https://www.vox.com/2020/3/30/21186822/immunity-to-covid-19-test-coronavirus-rt-pcr-antibody" target="_blank">help support the health care system</a> by caring for those who are infected.</p><p>Once communities pass the peak of the epidemic, the number of new infections will decline, while the number of <a href="https://www.newsweek.com/china-says-passed-peak-coronavirus-epidemic-covid-19-1491863" target="_blank">recovered people will increase</a>. As these trends continue, the risk of transmission will fall. Once the risk of transmission has fallen enough, community-level isolation and social distancing orders will begin to relax and businesses will start to reopen. Based on what other countries have gone through, it will be <a href="https://www.nature.com/articles/d41586-020-00154-w" target="_blank">months until the risk of transmission is low</a> in the U.S.</p><p>But before any of this can happen, the U.S. and the world need to make it through the peak of this pandemic. Social distancing works to slow the spread of infectious diseases and <a href="https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/what-you-can-do.html" target="_blank">is working for COVID-19</a>. Many people will <a href="https://www.yalemedicine.org/stories/2019-novel-coronavirus/" target="_blank">need medical help to recover</a>, and social distancing will slow this virus down and give people the best chance to do so.</p>
By Elizabeth Claire Alberts
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By Zulfikar Abbany
Chemical leavening<p>If you like a little heft in your loaf, you will need a leavening agent.</p><p>For those short on time, you can use baking soda. That's a chemical compound of sodium bicarbonate mixed with potassium bitartrate, or cream of tartar.</p><p>Soda breads have their traditions in parts of eastern and central Europe, and in Ireland and Scotland, with Melrose loaves and "farls."</p><p>They can taste a bit bland, though, and are often considered only as an emergency solution on Sundays. No disrespect intended: They taste just fine fresh from the oven.</p><p>Whether it's chemical or more "natural," leavening relies largely on the production of carbon dioxide.</p><p>When you mix an acid, such as vinegar, buttermilk, yogurt or apple cider, with an alkaline compound like baking soda, you get CO2. That CO2 creates bubbles, which in turn capture steam in the oven and allow a bread to rise.</p><p><span></span>But it's better with yeast. Tastes better, too. It just takes more time. </p>
What is yeast?<p>There are yeasts all around us — on grains, in the air, in biofuels. It even lives inside us, but that's not always a good thing.</p><p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1090575/pdf/1471-2334-5-22.pdf" target="_blank">Candida yeast</a> can cause infections of the skin, feet, mouth, penis or vagina if it builds up too much in the body.</p><p>One of the most common yeasts, however, is <em>Saccharomyces cerevisiae</em>. That's <a href="https://www.dw.com/en/an-early-beer-archaeologists-tap-ground-at-worlds-oldest-brewery/a-45480731" target="_blank">"brewer's"</a> or "baker's" yeast.</p><p>You can get fresh baker's yeast, often in 42-gram (1.48-ounce) cubes, or as dried yeast (quick action or active, which requires rehydration) in a sachet of 7 grams.</p><p>There's little difference: One is compressed and the other is dehydrated and granulated. But they do the same thing, essentially. </p><p>Some commercial yeast producers add molasses and other nutrients. But natural yeast has plenty of useful nutrients in it anyway, including B group vitamins, so who knows whether it's good or necessary to add them. </p>
How does yeast work?<p>When you mix flour, yeast and water, you set off a veritable chain reaction. Enzymes in the wheat convert starch into sugar. And the yeast creates enzymes of its own to convert those sugars into a form it can absorb.</p><p>The yeast "feeds" on the sugars to create carbon dioxide and alcohol. The yeast burps and farts, releasing gases into the mix, and that creates bubbles to trap CO2. </p><p>It's a vital fermentation process that breaks down the gluten in the flour and helps make your bread more digestible.</p><p>The yeast cells split and reproduce, generating lactic and carbonic acid, raising the temperature and ultimately adding flavor to the mix.</p><p>The longer you leave the yeast to do its thing, the better for your bread. Time is more important than the amount of yeast. </p><p>In fact, that's an enduring question — how much yeast? I'll use 20 grams fresh yeast for 500 grams of flour. Others say that's enough yeast for 1 kilo. If you are converting a dry-yeast recipe to fresh yeast, some bakers advise tripling the weight. So, if a sachet of dried yeast is 7 grams, your fresh yeast is 21 grams.</p><p><span></span>But that also depends on the flours you are using, temperatures in the bowl and the room, and a host of other things. You'll just have to experiment and see. No number of books (and I've read a stack on bread) will help as much as trial and error.</p>
Wild yeast: Sourdough<p>So, good bread needs time. If you have a lot of time, why not move it up a notch and grow wild yeast — a sourdough starter — in your own home?</p><p>A sourdough starter is not to be mistaken (as it often is) for the leaven, or "mother," "sponge," or <em>levain</em>. That's more a second stage, a descendant of the starter. You take a scoop from your starter and add it to another flour and water mixture when you prepare the dough for a new loaf. </p><p>The sourdough process utilizes yeasts naturally present in flour and … yet more time. A longer fermentation process allows a richer lactic acid bacteria <em>lactobacilli</em> or LAB to evolve, and that can be healthy for your gut microbiome.</p><p>It's simple enough to start a sourdough starter. All you need is flour, warm water and time.</p><p>Some suggest equal measures of whole-grain flour and water at 28 degrees Celsius (82 degrees Fahrenheit), some say room temperature — just don't let the water exceed 40 C or the yeasts will die. Some suggest two parts flour to three parts water. But it's up to you whether you want a drier or wetter starter. You will know only through experimentation. </p><p>Some say you should filter tap water to remove chemicals like fluoride and avoid using water that's boiled and then cooled. Others say that really doesn't matter.</p><p>The main thing is, keep it clean and give it time. Days, weeks, months and years.</p>
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