What Does Plastic Do to the Endocrine System?
Emma Bryce | March 13, 2024 | Scientific American
The translucent exterior of a plastic soda bottle hides a secret in plain sight: hundreds of synthetic chemicals embedded in its seemingly innocuous material. These chemicals give the plastic its structure, flexibility and durability, among other qualities—the same traits that also make plastic last for centuries, causing it to accumulate and endure in nature.
Before this plastic enters the natural ecosystem, the chemicals inside can leach out of water bottles and other food containers, entering the body and potentially endangering human health, according to a mounting body of research. In particular, plastic contains endocrine-disrupting chemicals (EDCs) that could wreak havoc on certain messaging systems in the human body.
As their name suggests, these chemicals act on the endocrine (hormone) system in possibly dangerous ways. Most direct research into their health effects comes from studies on animals and lab-grown cells (testing these chemicals directly on the human body would be unethical), as well broader epidemiological studies in humans that have linked EDC exposure with adverse health outcomes. But research has a hard time keeping pace with the rapid and constant creation of new chemicals. There are more than 16,000 chemicals used in plastics manufacturing, and over 1,000 industrial chemicals used today are suspected EDCs. But aside from a small percentage of substances that are regulated, plastic producers aren’t required to disclose the chemical ingredients they use.
The specific cocktail of chemicals that lurks in the products we buy is therefore something of a mystery.“You know what’s in a packet of biscuits when you buy it, but you don’t know what [chemicals are] in the wrapping,” says Sarah Dunlop, a neuroplasticity researcher at the University of Western Australia and director of Plastics & Human Health at the Minderoo Foundation, a charitable organization.
What we do know is that EDCs are packed into plastics and that they canleach out. And despite the slow pace of research, the evidence has been steadily accumulating for decades. It now paints an increasingly concerning picture that should motivate us to regulate plastic production, several researchers say.
EDCS ARE UBIQUITOUS IN PLASTICS
EDCs cover a vast family of substances that include many synthetic industrial chemicals such as bisphenols, flame retardants, per- and polyfluoroalkyl substances (PFAS), or “forever” chemicals, and phthalates, among others. They’re found in everything from electronics to carpets and paints to cosmetics—and in plastics. In this material, their applications are broad: phthalates are known as plasticizers and give many plastics their flexibility and durability, whereas PFAS have nonstick qualities that come in handy in the production of molds for plastic products—and leave behind a telltale chemical residue that can migrate into whatever substance the plastic goes on to contain. EDCs also turn up in other places we might least expect. Following a safety assessment, the FDA last month announced grease-proofing substances containing PFAS had been completely phased out for food packaging paper and paperboard by manufacturers in the U.S.
