You’ve probably been hearing the term PFAS in the news lately as states and the U.S. government consider rules and guidelines for managing these “forever chemicals.”

Even if the term is new to you, chances are good that you’re familiar with what PFAS do. That’s because they’re found in everything from nonstick cookware to carpets to ski wax.

PFAS stands for per- and polyfluoroalkyl substances, which are a large group of human-made chemicals – currently estimated to be around 9,000 individual chemical compounds – that are used widely in consumer products and industry. They can make products resistant to water, grease and stains and protect against fire.

Waterproof outdoor apparel and cosmetics, stain-resistant upholstery and carpets, food packaging that is designed to prevent liquid or grease from leaking through, and certain firefighting equipment often contain PFAS. In fact, one recent study found that most products labeled stain- or water-resistant contained PFAS, and another study found that this is even true among products labeled as “nontoxic” or “green.” PFAS are also found in unexpected places like high-performance ski and snowboard waxes, floor waxes and medical devices.

At first glance, PFAS sound pretty useful, so you might be wondering “what’s the big deal?”

The short answer is that PFAS are harmful to human health and the environment.

Some of the very same chemical properties that make PFAS attractive in products also mean these chemicals will persist in the environment for generations. Because of the widespread use of PFAS, these chemicals are now present in water, soil and living organisms and can be found across almost every part of the planet, including Arctic glaciers, marine mammals, remote communities living on subsistence diets, and in 98% of the American public.

The Environmental Protection Agency recently issued new warnings about their risk in drinking water even at very low levels.

Health risks from PFAS exposure

Once people are exposed to PFAS, the chemicals remain in their bodies for a long time – months to years, depending on the specific compound – and they can accumulate over time.

Research consistently demonstrates that PFAS are associated with a variety of adverse health effects. A recent review by a panel of experts looking at research on PFAS toxicity concluded with a high degree of certainty that PFAS contribute to thyroid disease, elevated cholesterol, liver damage and kidney and testicular cancer.

Further, they concluded with a high degree of certainty that PFAS also affect babies exposed in utero by increasing their likelihood of being born at a lower birth weight and responding less effectively to vaccines, while impairing women’s mammary gland development, which may adversely impact a mom’s ability to breastfeed.

The review also found evidence that PFAS may contribute to a number of other disorders, though further research is needed to confirm existing findings: inflammatory bowel disease, reduced fertility, breast cancer and an increased likelihood of miscarriage and developing high blood pressure and preeclampsia during pregnancy. Additionally, current research suggests that babies exposed prenatally are at higher risk of experiencing obesity, early-onset puberty and reduced fertility later in life.

Collectively, this is a formidable list of diseases and disorders.

Who’s regulating PFAS?

PFAS chemicals have been around since the late 1930s, when a DuPont scientist created one by accident during a lab experiment. DuPont called it Teflon, which eventually became a household name for its use on nonstick pans.

Decades later, in 1998, Scotchgard maker 3M notified the Environmental Protection Agency that a PFAS chemical was showing up in human blood samples. At the time, 3M said low levels of the manufactured chemical had been detected in people’s blood as early as the 1970s.

Despite the lengthy list of serious health risks linked to PFAS and a tremendous amount of federal investment in PFAS-related research in recent years, PFAS haven’t been regulated at the federal level in the United States.

The EPA has issued advisories and health-based guidelines for two PFAS compounds – PFOA and PFOS – in drinking water, though these guidelines are not legally enforceable standards. And the Agency for Toxic Substances and Disease Registry has a toxicological profile for PFAS.

Federal rules could be coming. Congress is considering legislation to ban PFAS in some food packaging. The EPA has a road map for PFAS regulations it is considering, including regulations involving drinking water. The Biden administration has said it also expects to list PFOA and PFOS as hazardous substances under the Superfund law, a move that worries utilities and businesses that use PFAS-containing products or processes because of the expense of cleanup.

States, meanwhile, have been taking their own actions to protect residents against the risk of PFAS exposure.

At least 23 states have laws targeting PFAS in various uses, such as in food packaging and carpets. But relying on state laws places burdens on state agencies responsible for enforcing them and creates a patchwork of regulations which, in turn, place burdens on business and consumers to navigate regulatory nuances across state lines.

So, what can you do about PFAS?

Based on current scientific understanding, most people are exposed to PFAS primarily through their diet, though drinking water and airborne exposures may be significant among some people, especially if they live near known PFAS-related industries or contamination.

The best ways to protect yourself and your family from risks associated with PFAS are to educate yourself about potential sources of exposures.

Products labeled as water- or stain-resistant have a good chance of containing PFAS. Check the ingredients on products you buy and watch for chemical names containing “fluor-.” Specific trade names, such as Teflon and Gore-Tex, are also likely to contain PFAS.

Check whether there are sources of contamination near you, such as in drinking water or PFAS-related industries in the area. Some states don’t test or report PFAS contamination, so the absence of readily available information does not necessarily mean the region is free of PFAS problems.

For additional information about PFAS, check out the Agency for Toxic Substances and Disease Registry, EPA and U.S. Centers for Disease Control and Prevention websites or contact your state or local public health department.

If you believe you have been exposed to PFAS and are concerned about your health, contact your health care provider. The Agency for Toxic Substances and Disease Registry has a succinct report to help health care professionals understand the clinical implications of PFAS exposure.

This article was updated July 8, 2022, with new legislation signed in Rhode Island and Hawaii.

Kathryn Crawford, Assistant Professor of Environmental Health, Middlebury

This article is republished from The Conversation under a Creative Commons license. Read the original article.

For most of human history, the stars blazed in an otherwise dark night sky. But starting around the Industrial Revolution, as artificial light increasingly lit cities and towns at night, the stars began to disappear.

We are two astronomers who depend on dark night skies to do our research. For decades, astronomers have been building telescopes in the darkest places on Earth to avoid light pollution.

Today, most people live in cities or suburbs that needlessly shine light into the sky at night, dramatically reducing the visibility of stars. Satellite data suggests that light pollution over North America and Europe has remained constant or has slightly decreased over the last decade, while increasing in other parts of the world, such as Africa, Asia and South America. However, satellites miss the blue light of LEDs, which are commonly used for outdoor lighting – resulting in an underestimate of light pollution.

An international citizen science project called Globe at Night aims to measure how everyday people’s view of the sky is changing.

Measuring light pollution over time

Relying on citizen scientists makes it much easier to take multiple measurements of the night sky over time from many different places.

To provide data to the project, volunteers enter the date and time, their location and local weather conditions into an online reporting page anytime an hour or more after sunset on certain nights each month. The page then shows eight panels, each displaying a constellation visible at that time of year – like Orion in January and February, for example. The first panel, representing a light-polluted night sky, only shows the few brightest stars. Each panel shows progressively more and fainter stars, representing darker and darker skies. The participant then matches what they see in the sky with one of the panels.

The Globe at Night team launched the report page as an online app in 2011, just at the beginning of widespread adoption of LEDs. In the recent paper, the team filtered out data points taken during twilight, when the Moon was out, when it was cloudy or when the data was unreliable for any other reason. This left around 51,000 data points, mostly taken in North America and Europe.

The data shows that the night sky got, on average, 9.6% brighter every year. For many people, the night sky today is twice as bright as it was eight years ago. The brighter the sky, the fewer stars you can see.

If this trend continues, a child born today in a place where 250 stars are visible now would only be able to see 100 stars on their 18th birthday.

Causes, impacts and solutions

The main culprits driving increasing brightness of the night sky are urbanization and the growing use of LEDs for outdoor lighting.

The loss of dark skies, both from light pollution and also from increasing numbers of satellites orbiting Earth, threatens our ability as astronomers to do good science. But everyday people feel this loss too, as the degradation of dark skies is also a loss of human cultural heritage. Starry night skies have inspired artists, writers, musicians and philosophers for thousands of years. For many, a star-filled sky provides an irreplaceable sense of awe.

Light pollution also interferes with the daily cycle of light and dark that plants and animals use to regulate sleep, nourishment and reproduction. Two-thirds of the world’s key biodiversity areas are affected by light pollution.

Individuals and their communities can make simple changes to reduce light pollution. The secret is using the right amount of light, in the right place and at the right time. Shielding outdoor light fixtures so they shine downward, using bulbs that emit more yellow-colored light instead of white light and putting lights on timers or motion sensors can all help reduce light pollution.

The next time you are far away from a major city or another source of light pollution, look up at the night sky. A view of the roughly 2,500 stars you can see with the naked eye in a truly dark sky might convince you that dark skies are a resource worth saving.

Chris Impey, University Distinguished Professor of Astronomy, University of Arizona and Connie Walker, Scientist, National Optical-Infrared Astronomy Research Laboratory

This article is republished from The Conversation under a Creative Commons license. Read the original article.