What have the hands of humankind gained.. Will the sky rain cancer?

A recent study concluded that rainwater contains high levels of man-made chemicals that may play a role in cancer.

The study was conducted by researchers at Stockholm University and ETH Zürich, and was published in the Journal of Environmental Science & Technology, and the British newspaper The Independent wrote about it .

These chemicals are known as PFAs , and include  perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). . They are man-made, and some have been linked to cancer in humans.

These chemicals consist of a series of fluorine atoms, and the danger is that they do not degrade in the environment; Which is harmful to our health, according to a report in Deutsche Welle .

More than 4,500 man-made substances fall under the classification of these chemicals, and they are found all around us; In soil, drinking water, animal foods, and even inside our bodies.

PFAS materials are known to be highly stable, meaning they are resistant to decomposition, and thus are known as “forever chemicals”, and their continued presence in the atmosphere is due to their properties and the natural processes that constantly work to recycle PFAs. FAS" to the atmosphere from the surface environment.

Even in remote parts of the world, the level of PFAS in the atmosphere has become so high that rainwater is now "unsafe to drink", according to newly issued water quality guidelines.

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The guideline values ​​for PFAS in drinking water, surface water and soil have been significantly revised due to increased awareness of their toxicity, as well as the threats they pose to health and nature.

The changes mean that levels of these chemicals in rainwater "are now ubiquitous above guideline levels," according to the researchers.

Scientists studied from these materials, the levels of 4 selected perfluoroalkyl acids (PFAAs), in rainwater, soil and surface water, namely:

Perfluorooctane sulfonic acid (PFOS).

Perfluorooctanoic acid (PFOA).

Perfluoroalkyl acid (PFHxS).

Perfluoronanoic acid (PFNA).

They compared it to recently proposed indicative levels.

The scientists found the following:

Levels of PFOA and PFOS in rainwater often significantly exceed the US Environmental Protection Agency's (EPA) lifetime drinking-water advisory levels.

The sum of the four BFAs mentioned above in rainwater is often higher than the Danish drinking water limit values.

The levels of PFOS in rainwater are often higher than the environmental quality standards for inland surface waters of the European Union.

The researchers conclude that the global spread of these four substances into the atmosphere has exceeded the planetary limits of chemical pollution.

“There has been a staggering decrease in the guideline values ​​for PFAS” in drinking water in the past 20 years, said Ian Cousins, lead researcher on the study team and a professor in the Department of Environmental Sciences at Stockholm University. One known in the PFAS category, the carcinogenic perfluorooctanoic acid (PFOA), is 37.5 million times greater in the United States.

"Based on the latest US guidelines on perfluorooctanoic acid (PFOA) in drinking water, rainwater everywhere can be considered unfit for drinking," he added.

"Although in the industrialized world we don't drink rainwater very often, many people around the world expect drinking water to be safe and to provide our many drinking water sources," Professor Cousins ​​said.

When were BFAs invented?

The invention of PFAs dates back to around 1938 with the invention of the first chemical of its kind known as Polytetrafluoroethylene PTFE.

The invention of polytetrafluoroethylene came due to its ability to protect metals from corrosion at incredibly high temperatures, so it was used in the atomic bomb first, but soon this material appeared in homes all over the world, and was used to paint frying pans, according to a report in Deutsche Welle.

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Do these substances exist in our bodies?

According to a previous report in the Guardian, 98% of Americans contained BFAs in their blood , while studies in other countries revealed BFAs were found in all tested mothers' milk samples. In Germany, it was found that every child contained permanent chemicals, and in one fifth of the cases the concentrations exceeded critical levels.

What are the potential harms of BFAS?

BFAs may be linked to growth problems, cancer, liver damage, immune system disorders, vaccine resistance, thyroid disease, impaired fertility, and high cholesterol.

BFAs are described as "possibly carcinogenic" to humans by the US Environmental Protection Agency (EPA) and the International Agency for Research on Cancer (IARC), according to a report in the Guardian.

Several studies of PFOS and PFOA in both humans and animals have shown a wide range of potential health effects, including decreased fertility among women, decreased sperm count, lower birth weight, cancer, and death among the animals studied. .

Bioaccumulate

According to the Minnesota Pollution Control Agency, some PFAs are stable, meaning they don't break down in the environment, and some are bioaccumulative too, meaning the amount builds up in the body over time. BFAs have been found both in the environment and in blood samples of the general population of the United States.

Studies of poisoning degrees, conducted on animals exposed to some PFAS acids, confirm links between chemicals and changes in cholesterol levels in the body, hormones, and the immune system. Decreased fertility and increased risk of some types of cancer.

Studies in which animals were given high levels of PFAS showed effects including lower birth weight, delayed puberty and higher cholesterol levels.

Animal studies like this help scientists understand what might happen to humans. Some of these effects have also been observed in humans with higher levels of PFAS in their blood. Low immune responses to vaccination have been reported in humans, ie it is not as effective as it should be.