IN these times of widespread severe drought as well as overwhelming rains it is unfortunate that captured rainwater is not safe to drink no matter where you are. The first article, from LiveScience coveres the dangers of drinking rain water. The second article, from NBC NEWS offers some hope to address the major problem of rainwater, and actually all water which seems to be polluted with PFAS......
Is drinking rainwater safe?
New evidence suggests it may be riskier than previously thought.
If you stick out your tongue on a rainy day, you might think the drops you've tasted are the same as the water that comes out of your tap. But rainwater actually contains many microscopic ingredients that get filtered out before it is pumped into your home.
So is it safe to collect and drink rainwater?
There are a number of contaminants that can end up in the rainwater, such as bacteria, viruses, parasites, dust, smoke particles and other chemicals, according to the Centers for Disease Control and Prevention (CDC). If you collect rainwater from a roof, it could also contain traces left by animals, such as bird poop, and if the roof or drainpipes are old, materials such as asbestos, lead and copper could also end up in your tank. If rainwater is stored in an open container, it also may be full of insects and decaying organic matter, such as dead leaves. For these reasons, the CDC advises against collecting and drinking rainwater but recommends using it for other purposes, such as watering plants.
However, the levels of these contaminants can vary significantly depending on where you live, and the risk of illness depends largely on how much rainwater you drink. If you have a clean collection system and properly sterilize the rainwater, either with chemicals or by boiling and distillation, then most of the impurities can be removed. This has led to a lot of confusion about whether rainwater is unsafe to drink.
But now, in the modern age of human-made chemicals, there's a new risk associated with drinking rainwater. In a study published in August 2022 in the journal Environmental Science & Technology, researchers found that rainwater all over the globe has concentrations of toxic PFAS (per- and polyfluorinated alkyl substances) that exceed health guidelines. These findings mean that rainwater is definitely unsafe to drink, especially if it is untreated.
What are PFAS?
PFAS is a collective term for more than 1,400 human-made chemicals and substances that have historically been used for a range of products, including textiles, firefighting foams, nonstick cookware, food packaging, artificial turf and guitar strings, lead study author Ian Cousins, an environmental chemist at Stockholm University in Sweden, told Live Science in an email.
However, "the current understanding of biological impacts is based primarily on studies of four perfluoroalkyl acids (PFAAs)," which is a subgroup of PFAS, Cousins said. These PFAAs include perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA), which were the main focus of the study, he added.
Past research has shown that these chemicals are extremely toxic and can cause a wide range of problems — including different types of cancer, infertility, pregnancy complications, developmental problems, immune system conditions, and various diseases of the bowels, liver and thyroid — as well as potentially decrease the effectiveness of vaccines in children, Cousins said. PFAS are also likely to cause additional damage to the environment, but this idea has not been studied in as much detail, he added.
This evidence has led PFAAs and most other PFAS to be either banned or heavily restricted within the past 20 to 30 years, except in China and some other Asian countries, Cousins said. The health guidelines surrounding PFAS have also been readjusted to reflect the chemicals' toxicity. For example, in the U.S., the safe level of exposure to PFOA as determined by the Environmental Protection Agency (EPA) is 37.5 million times less than it once was, according to a statement by the researchers.
PFAS do not break down very easily, which means they remain in the environment long after they are produced and are just as toxic, Cousins said. This has led scientists to nickname PFAS "forever chemicals," he added.
Contaminated rainwater
In the study, researchers gathered data from rainwater samples collected across the globe, revealing that PFAS are still abundant in rainwater everywhere on Earth in concentrations above the safety guidelines set by the EPA and other similar regulatory bodies in other countries.
Experts had hoped that concentrations of PFAS might have started declining by now, but this is clearly not the case, Cousins said. Instead, researchers think PFAS represent a new planetary boundary, a conceptual limit beyond which something becomes unsafe to humans, that we have already exceeded, he added.
The most striking finding was that PFOA levels in rainwater are at least 10 times over the EPA's safe level at every location sampled on the planet, including the Tibetan Plateau and Antarctica.
The researchers are still unsure exactly how PFAS are being transported to the most remote parts of the globe, Cousins said. The team hypothesizes that PFAS on the surface of the ocean are being reinjected into the atmosphere by ocean spray and then transported to other regions, where they fall as rain; they plan to test this hypothesis in future research. It is also possible that PFAS are still leaking into the environment from landfills, Cousins added.
It is too early to predict the overall public health impacts PFAS-rich rainwater will cause around the globe, but they might already be underway. "We have been exposed at even higher levels for the past 20 to 30 years already," Cousins said. "We just now understand better the potential consequences of that exposure."
The impact of PFAS will likely be greater in developing countries where millions of people rely on rainwater as their only source of drinking water, Cousins said. But even in certain regions of developed nations, such as Western Australia, drinking rainwater is still surprisingly common, he added.
Even if rainwater is properly treated, there is still no guarantee that PFAS will have been removed. PFAS can also be found in low levels in drinking water from taps and bottles, although often at safe levels.
The levels of PFAS will eventually decrease as they get cycled into the deep ocean, but this is a gradual process that could take many decades, Cousins said.
Harry is a U.K.-based staff writer at Live Science. He studied Marine Biology at the University of Exeter (Penryn campus) and after graduating started his own blog site "Marine Madness," which he continues to run with other ocean enthusiasts. He is also interested in evolution, climate change, robots, space exploration, environmental conservation and anything that's been fossilized. When not at work he can be found watching sci-fi films, playing old Pokemon games or running (probably slower than he'd like).
Originally published on Live Science.
PFAS chemicals are associated with low birth weight, thyroid disease and an increased risk of certain cancers.
PFAS, a class of synthetic chemicals used in the manufacture of consumer products, can linger permanently in the air, water and soil, which is why they're often referred to as "forever chemicals."
The chemicals are associated with low birth weight, high cholesterol, thyroid disease and an increased risk of certain cancers. A study published earlier this month found that exposure to high levels of PFOS — a type of PFAS once used to make items such as clothing and food packaging resistant to stains, grease and water — was associated with an increased risk of liver cancer. Its sister chemical, PFOA, has been associated with an increased risk of kidney cancer.
So scientists have tried for years to find ways to break down PFAS, an acronym for per- and polyfluoroalkyl substances. On Thursday, researchers at Northwestern University published a study showing that PFAS can be destroyed using two relatively harmless chemicals: sodium hydroxide or lye, a chemical used to make soap, and dimethyl sulfoxide, a chemical approved as a medication for bladder pain syndrome.
Previously, the only operational way to break down PFAS was to expose the particles to extremely high temperatures — sometimes above 1,800 degrees Fahrenheit — in an incinerator. But that energy-intensive process can still release harmful chemicals into the environment.
The new method appears to be safer and more energy-efficient. The Northwestern scientists added PFAS molecules to a solution of lye and dimethyl sulfoxide and exposed them to temperatures of up to 248 degrees Fahrenheit. The chemicals degraded into fluoride ions and other harmless byproducts.
"One specific portion of these molecules falls off and sets off a cascade of reactions that ultimately breaks these PFAS compounds down to relatively benign products," William Dichtel, a professor of chemistry at Northwestern University who co-authored the study, said on a call with reporters.
PFAS are nearly impossible to destroy because of their strong carbon-fluorine bonds. Brittany Trang, another co-author, compared the process of breaking apart the molecules to smashing a Lego block to bits.
Currently, PFAS can be filtered out of water but then need to be destroyed somehow. If the chemicals are dumped in a landfill or tossed in an incinerator, they can still pollute the environment.
"The current way that people will try to dispose of firefighting foams that contain PFAS is to incinerate them, but there has been evidence that these incinerators are actually just blowing the PFAS around the community in which the incinerator is located," Trang said. "So there’s a need for a method to get rid of PFAS in a way that does not continue to pollute."
Challenges in treating drinking water
PFAS were invented in the 1930s and used in nonstick and waterproof coatings for consumer goods starting in the 1940s and 50s. Since then, the chemicals have been found in all sorts of household items, including carpets, cookware and personal care products.
PFOA and PFOS were largely phased out of U.S. chemical and product manufacturing in the mid-2000s, but have since been replaced by a new group of PFAS chemicals called GenX. But the older chemicals persist in the environment, including in drinking water.
The Environmental Protection Agency issued new limits for safe levels of PFAS in drinking water in June. According to the agency, PFOA levels can be harmful above 0.004 parts per trillion, while PFOS levels can be harmful above 0.02 parts per trillion. The agency also set a limit of 10 parts per trillion for GenX.
The EPA acknowledged in a press release at the time that "some negative health effects may occur with concentrations of PFOA or PFOS in water that are near zero and below EPA’s ability to detect."
The Northwestern researchers broke apart PFAS molecules at higher concentrations than the EPA warns about, though they think the process could remove lower concentrations from water too.
However, although the new method was able to degrade PFOA and GenX chemicals, Dichtel said, PFOS can’t be destroyed in the same way. So the researchers are looking into other methods for that.
The Environmental Working Group, a research and advocacy group focused on toxic chemicals, monitors pollutants in drinking water and estimated in June that 2,000 U.S. communities had levels of PFAS in their drinking water that were above the EPA's new limits.
It will likely take several years for scientists to develop a solution that can be rolled out in these communities, said Christopher Sales, an associate professor of environmental engineering at Drexel University who was not involved in the new study.
"A lot of methods used to destroy [PFAS] haven't really been proven to destroy it at those really low, low concentrations," he said.
If the new approach were to be applied to water treatment on a wide scale, the water would likely need to go from a treatment facility to an off-site location. There, the PFAS could be extracted, then exposed to the necessary mixture of lye and dimethyl sulfoxide.
"The big question is whether or not this process could be scaled up," Sales said.
He said other researchers are also investigating ways to destroy PFAS at lower temperatures — perhaps even at room temperature.
Overall, the problem may require multiple solutions, Sales said: "I don't think there's one single silver bullet to treat PFAS."
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