"Forever chemicals" is a hot news item. The public is paying attention to them because they stick around for very long periods of time – including in your body – where they bioaccumulate. This has caused concern that they may cause cancer, although this has not been proven. Why does this group of chemicals stay around for so long? Chemistry explains.
"Forever chemicals"– good, bad, or otherwise? Per- and polyfluoroalkyl substances (PFAS) and perfluorooctane sulfonic acid (PFOS), aka, "forever chemicals," have been widely reported in the news recently. These chemicals are suspected of being carcinogens. (In organic chemistry, "per" means that all hydrogen atoms in the molecule have been replaced by another atom. "Poly" means that most of them have.) (Left) When all the alkyl hydrogen atoms of octanoic acid (top) are replaced by fluorine atoms (bottom), the compound perfluorooctanoic acid (PFOA) becomes "indestructible." (Right) There are 65,535 possible compounds that make up the "polyfluorooctanoic acid family" Blame ChatGPT for this. It's not precisely history repeating itself, but about 75 years ago, another class of forever chemicals, PCBs (polychlorinated biphenyls), made its way into the environment when General Electric began dumping huge quantities of these chemicals into the Hudson River over a 30-year period. Despite an enormous dredging project that began in 2009, it's been impossible to get them out of the river, despite an enormous dredging project that began in 2009. Because they are chemically inert PCBs had several industrial uses, including electrical transformers, hydraulic fluid, lubricants, and coatings. That's all well and good, but dumping the stuff into the Hudson was anything but. It will be impossible to remove all of the PCB waste. That waste will be with us forever. Two examples of polychlorinated biphenyls (PCBs). There are 209 possible PCBs, of which about 130 have been synthesized. What makes certain chemicals last "forever?" "Forever chemicals" are the exception, not the rule. Of the estimated 20 million known organic chemicals (1), roughly 5,000–almost all synthetic (2) — are "forever chemicals." These chemicals share certain properties that make them persist: chemical stability and resistance to enzymatic degradation (metabolism). This is why they were created in the first…