People perceive risk largely based on what we see, smell and taste. These senses serve us well when threats to our health and the environment are perceived.
We see and smell untreated wastewater and as such it is widely perceived as a threat to human health and the environment. The growing concern of scientists about the presence of antibiotic-resistant bacteria in wastewater confirmed the real threat. The Environment Agency also reports that pollution from sewage discharges is a major cause of poor river quality in England.
However, there are serious chemical hazards called perfluoroalkyl and polyfluoroalkyl substances (PFAS) that we cannot see because they are colorless and odorless. Now present in our drinking water and natural ecosystems, high exposure to these toxic chemicals can cause a range of negative health effects in humans and wildlife. These include an increased risk of certain cancers, kidney disease, cholesterol, reproductive and developmental disorders, and a reduced response to the vaccine.
Humans cannot see, smell or taste PFAS in our water. However, they pose a serious global threat. The actual risk of PFAS is high, but in my experience as a scientist working on environmental pollution, many people are unaware of it.
What are PFASs?
PFAS, first developed in the 1940s, is a large group of over 4,000 synthetic chemicals. Commonly known as “the everlasting chemicals”, their properties make them water and oil resistant and highly resistant to chemical and thermal degradation.
They are therefore components of various everyday products and as such are everywhere around us. Non-stick pans, waterproof rain jackets, flame retardant sofas and rugs, food packaging, makeup products and countless other items contain these chemicals.
But PFASs can survive in the environment for hundreds or thousands of years. Studies estimate that it takes an average of more than 1,000 years to reduce the chemical concentration of some PFASs in soil by 50%.
exposure to PFAS
Due to their persistence, PFASs are constantly accumulating in drinking water sources and oceans around the world. This can happen when contaminated water leaks from landfills into groundwater. PFAS in household items can also be leached into rivers and oceans through sewage systems.
In 2019, at least one PFAS was detected in 60% of public groundwater wells and 20% of private groundwater wells used as sources of drinking water in the eastern United States. In England, the Environment Agency analyzed 470 freshwater sites between 2014 and 2019 and found PFAS contamination in 97% of them.
Freshwater contaminants then accumulate in plants and animals, from where they can be transferred to humans through consumption.
In the city of Charleston, South Carolina, scientists recorded concentrations of 11 PFASs in six species of fish. Levels of the most prevalent chemical recorded in each species, perfluorooctane sulfonate, exceeded wildlife conservation guidelines in 83% of the whole fish tested. The consumption of wild fish is therefore a serious health problem for the local population.
Most people in the world have probably been exposed to PFAS. For example, in 2012, over 97% of Americans had detectable levels of PFAS in their blood.
However, unlike most other chemical pollutants, PFASs are able to undergo continuous hydrological processes and spread in the atmosphere. For example, scientists have recorded concentrations of PFAS in rainwater almost all over the world. This means that contamination can be largely irreversible.
Distributed through the water cycle, PFASs can contaminate remote corners of the planet and negatively affect wildlife. In Antarctica, the accumulation of one type of PFAS, perfluorobutanoic acid, in snow increased more than 200-fold between 1957 and 2015.
Scientists also found high concentrations of PFAS in Arctic algae. Algae are an important food source for zooplankton, and their contaminants make their way up the food chain to fish and shrimp, then to seals, and finally to apex predators such as polar bears. A study of East Greenland polar bears revealed that PFAS contamination can disrupt the polar bear’s endocrine system, which can negatively affect reproduction.
For many people, current PFAS exposure levels are unlikely to be high enough to warrant serious concern. However, exposure in some occupations, including firefighting and chemical manufacturing and processing, can be significantly higher. So is the risk to people whose drinking water or food sources have been contaminated.
Science and even Hollywood have warned us of the global chemical threat posed by PFAS. However, many of us do not see them as a threat.
This may be because PFASs are an “invisible” hazard and not as obvious as sewage or plastic pollution. But these toxic chemicals have accumulated in many of our water sources and are now interfering with natural ecosystems. Governments, scientists and the media must improve communication about the dangers of PFAS.
This article has been republished from The Conversation under a Creative Commons license. Read the original article.
Patrick Byrne receives funding from the Environmental Research Council.