Enlarge (credit: Layland Masuda )

Today, the Environmental Protection Agency announced that it has finalized rules for handling water supplies that are contaminated by a large family of chemicals collectively termed PFAS (perfluoroalkyl and polyfluoroalkyl substances). Commonly called "forever chemicals," these contaminants have been linked to a huge range of health issues, including cancers, heart disease, immune dysfunction, and developmental disorders.

The final rules keep one striking aspect of the initial proposal intact: a goal of completely eliminating exposure to two members of the PFAS family. The new rules require all drinking water suppliers to monitor for the chemicals' presence, and the EPA estimates that as many as 10 percent of them may need to take action to remove them. While that will be costly, the health benefits are expected to exceed those costs.

Going low

PFAS are a collection of hydrocarbons where some of the hydrogen atoms have been swapped out for fluorine. This swap retains the water-repellant behavior of hydrocarbons while making the molecules highly resistant to breaking down through natural processes—hence the forever chemicals moniker. They're widely used in water-resistant clothing and non-stick cooking equipment and have found uses in firefighting foam. Their widespread use and disposal has allowed them to get into water supplies in many locations.

Enlarge / Wetlands like this may end up a complicated patchwork of regulated and unregulated areas thanks to the latest Supreme Court decision. (credit: Stefano Madrigali )

On Thursday, the US Supreme Court issued a ruling that severely limits the EPA's ability to regulate pollution under the Clean Water Act. The ruling applies to wetlands that are connected to bodies of water that fall under the Clean Water Act's regulatory scheme, with the court now ruling that those connections need to be direct and contiguous in order for the act to apply. This would remove many wetlands that are separated by small strips of land—including artificial structures like levees—from oversight by the EPA.

The decision is a somewhat unusual one, in that all nine justices agree that the people who originally sued the EPA should prevail. But there was a very sharply worded 5-4 disagreement over what the word "adjacent" means.

Whose waters are these?

The Clean Water Act was a major piece of environmental regulation, put in place due to the sometimes horrific pollution prevalent in the early 1970s. Its text applies regulations to the "waters of the United States," a term that has proven sufficiently vague that it has been the subject of a variety of lawsuits and federal regulatory policies over the years. A number of geographic features—seasonal streams, human-made water features, and marshlands without a direct connection to rivers—have all been subject to dispute.

Enlarge / The EPA headquarters in Washington, DC. (credit: crbellette )

On Tuesday, the Environmental Protection Agency announced that it had started the process that will see drinking water regulations place severe limits on the levels of several members of the PFAS (perfluoroalkyl and polyfluoroalkyl substances) chemical family. PFAS are widely used but have been associated with a wide range of health issues; their chemical stability has also earned them the term "forever chemicals." The agency is currently soliciting public feedback on rules that will mean that any detectable levels of two chemicals will be too much.

PFAS are a large group of chemicals that have uses in a wide range of products, including non-stick cooking pans, fire control foams, and waterproof clothing. They're primarily useful because of their water-repellant, hydrophobic nature. That nature also tends to keep them from taking part in chemical processes that might otherwise degrade them, so contamination problems tend to stick around long after any PFAS use. And that's bad, given that they seem to have a lot of negative effects on health—the EPA lists cancer risks, immune dysfunction, hormone signaling alterations, liver damage, and reproductive issues.

Back in 2021, the Biden administration announced that it was starting a research and regulatory program focused on PFAS and issued preliminary guidance on acceptable levels last year. Today's announcement is the start of a formal rulemaking process that will see the development of legally binding limits. This process involves the EPA publishing proposed rules to allow the public and interested parties a chance to provide feedback. Once that feedback is addressed, formal rules will be published.

Enlarge (credit: Helge Thomas (CC-BY-2.0) )

Ecotoxicologist Craig Downs describes his main work goal as “preventing zombies”—communities of coral or other marine creatures that appear to be thriving, but upon closer inspection, turn out to be composed only of adults lacking the ability to reproduce. These populations are like the “ living dead ,” a generation away from vanishing, according to scientists who discovered them in dying reefs across the Caribbean in 2016.

Globally, coral reefs are in decline for a number of reasons , including climate change, coastal development, and pollution. Over the years, Downs, executive director of Haereticus Environmental Laboratory in Virginia, has studied sunscreen, microplastics, and most recently, beach showers, in an effort to understand the effects of these human-made substances on some of the world's most popular vacation destinations. His latest study , published in July, could also breathe new life into an old law.

In April, the Clean Water Act , the keystone US law on water pollution, took what many environmentalists describe as a tough hit. In a controversial shadow docket decision , the Supreme Court voted to remove states’ power to block federally approved, but environmentally damaging, projects. Commentators decried the attempt to strip states of the right to protect their own waters, one of the core principles enshrined in the act.