"Forever Chemicals" Build Up Through Food Chain, Raising Alarms for Human Health

UNSW-led research shows PFAS “forever chemicals” can double at each step of the food chain, leaving top predators, including humans, with much higher exposure. The study warns newer PFAS may accumulate faster and urges stricter global regulation.

New global research led by scientists from the University of New South Wales (UNSW) has revealed that levels of PFAS chemicals can double at each level of the food chain. This means that animals at the top of the chain, like dolphins, birds of prey and even humans, may be exposed to significantly higher concentrations of these chemicals compared to those lower down.

To understand how this happens, consider a dolphin swimming near the coast of China. The dolphin eats fish, which in turn eat smaller fish. These smaller fish feed on plankton and algae that have absorbed tiny amounts of PFAS from the water. While each individual meal contains only a small amount, the chemicals accumulate over time. By the time they reach top predators, the concentration of PFAS becomes much higher.

Forever Chemicals

PFAS stands for per- and polyfluoroalkyl substances. These chemicals are often referred to as “forever chemicals” because they do not break down naturally in the environment. They are a group of over 12,000 man-made chemicals used in various everyday items such as non-stick cookware, food packaging, stain-resistant fabrics, cleaning products, and fire-fighting foam.

The researchers looked at 119 food chains, both on land and in water, from different parts of the world. Their findings, published in Nature Communications, showed that PFAS concentrations increase rapidly as they move up the food chain. On average, the level doubles with each step, which means that animals at the top of the chain can carry extremely high levels of these chemicals relative to their surroundings.

Human Exposure

Since humans are also at the top of the food chain, our diet can be a major source of PFAS exposure. Foods like fish, seafood, and meat from animals higher up the chain have been found to contain higher levels of these chemicals. PFAS has already been detected in the blood of almost everyone around the world.

Some studies have pointed to potential health problems linked to PFAS exposure, including certain cancers, issues with the immune system, and hormonal imbalances. However, Australian health authorities say there is still not enough clear evidence to directly link PFAS to specific diseases, and more research is needed to fully understand the risks.

Unequal Impact

The UNSW team analyzed 72 different PFAS compounds and found that not all of them behave the same way. Some build up much more quickly in the environment than others. This is concerning because several newer PFAS chemicals marketed as safer alternatives to older versions were found to accumulate even more strongly in food chains.

This raises the possibility that replacing banned PFAS with newer alternatives may not fix the problem and could even make it worse. The researchers warn that these chemicals could become just as widespread and harmful if action is not taken soon.

The study’s authors are calling for immediate changes in how PFAS are regulated globally. Currently, most regulations focus on how toxic a chemical is in the short term, rather than how much it accumulates over time in animals and humans.

The researchers argue that chemicals which build up easily in the food chain should be subject to stricter controls, especially those that are still unregulated. They also emphasize that decisions should be based on the specific behaviour of each chemical, rather than treating all PFAS as a single group.

Need for Action

While PFAS levels generally double at each level of the food chain, the rate at which they accumulate varies between different chemicals. Because of this, the researchers believe a more targeted, science-based approach to regulation is essential.

Overall, the study highlights an increasing environmental and health concern. Even low levels of PFAS in water and soil can lead to much higher exposures for wildlife and people over time. Without stronger controls and better understanding, these “forever chemicals” may continue to pose long-term risks to ecosystems and human health.