Harmful substances appear! Many people in Japan have excessive levels of organic fluorine compounds!

Audit expert: Gan Qiang

Lecturer at Beijing Institute of Technology, PhD in Applied Chemistry

Following the release of nuclear contaminated water, Japan has faced a new pollution problem. According to CCTV.com on November 13, the levels of per- and poly-fluoroalkyl substances in rivers and groundwater in many cities in the Kansai region of Japan have recently been found to exceed the standard.

Source | CCTV4

Two months ago, a local non-governmental organization with professional knowledge and medical qualifications helped residents conduct blood tests. The results showed that 31 out of 87 people tested had excessive levels of perfluorinated and polyfluoroalkyl substances in their bodies.

What exactly are “perfluorinated and polyfluoroalkyl substances”? What harm do they cause to the human body? How do they enter the human body?

1What are perfluorinated and polyfluoroalkyl substances?

Per- and polyfluoroalkyl substances (PFASs) refer to a class of synthetic compounds in which hydrogen atoms on the carbon skeleton are partially or completely replaced by fluorine atoms, with a general structural formula of CnF2n+1-R. Due to the presence of CF bonds, PFAS has strong surface activity (adding water can reduce the surface tension of water), chemical and thermal stability (not easy to react chemically), hydrophobicity and oleophobicity. The half-life of PFAS (self-transformation into harmless elements) (the time when the concentration drops to half and decomposes into other substances) is as long as 4-10 years. It is highly stable and extremely difficult to degrade. It is easy to accumulate in the environment and organisms, causing a variety of adverse reactions, posing a serious threat to the biological environment. Among them, perfluorooctanesulfonic acid (PFOS) and its salts and perfluorooctanoic acid (PFOA) have been listed in the priority list of persistent organic pollutants (POPs) by the United Nations Environment Programme.

Source: Related papers (pictures are drawn based on chemical structures)

Based on the performance of animals after being affected by PFAS, combined with epidemiology, the researchers finally concluded that PFOS and PFOA are associated with high levels of serum cholesterol, thyroid disorders, pregnancy-induced hypertension, ulcerative colitis, and some cancers. The 2018 draft toxicity assessment of PFAS by the U.S. Environmental Protection Agency (EPA) found that the substance affects the kidneys, immune system, liver, reproductive system, and organ development. Researchers said that both adults and children should be aware that such substances may invisibly pollute water sources and cause irreversible damage to the human body. Taking the situation in Japan as an example, the fertility of adults in some areas may have been affected, and the healthy growth of children may have become a luxury, and in severe cases, they may suffer from multiple cancers. In addition, studies have found that PFAS in surface soil and ground dust can directly accumulate in the human body and pose a potential threat after entering the respiratory tract through the atmosphere.

2 Sources and transmission routes of perfluorinated and polyfluoroalkyl substances

It is not difficult to find that PFAS has "fluorine" in its name, which is different from the "radiation" we know in the hospital. The "fluorine" here is an element, and the compounds containing this element can be collectively referred to as "fluoride". In modern times, with the rapid development of the modern chemical industry, the value of fluoride has gradually been discovered and produced. However, in its production, transportation and use, PFAS will inevitably be discharged into the atmosphere. Therefore, fluoride industrial parks are usually important point sources of PFAS in the surrounding atmosphere and even in remote areas. Studies have shown that PFAS emitted by fluoride industrial parks can drift with the atmosphere up to 150 kilometers away.

Source | Pexels

PFAS can be used as an additive in various industrial and civilian consumer products such as aqueous film-forming foams (AFFF), non-stick pans, stain-resistant carpets, food packaging, textiles, etc., and PFAS can be released during their use. Airports, chemical plants, oil companies (oil storage tanks) and emergency responses at military bases, as well as firefighting training, are key places for PFAS emissions. This also reveals the culprit that endangers the health of the Japanese people at the beginning of the article. In recent years, accidents have occurred frequently at US military bases in Japan, and they have a bad record in terms of physical equipment damage, soldier style, and pollution control. The PFAS content in the blood tests of residents in the Kansai region exceeded the standard, and the surrounding US military bases are probably to blame.

For soil, the main source of PFAS is the direct discharge of solid waste containing PFAS. After PFAS enters the soil in solid form, it is generally not too dispersed and spreads slowly. The atmosphere and water bodies (including surface water and groundwater) are important media and driving forces for the spread of PFAS from emission sources to the soil. Under their influence, the migration rate of PFAS is much higher than that of direct migration with soil as a carrier. The migration process of PFAS may also be affected by natural climate change and human factors. Relevant surveys in the East China region (including Shandong, Jiangsu and Zhejiang) have also fully demonstrated the role of rainfall in promoting the atmospheric deposition of PFAS in the region.

Source | Liu Haoran, Xing Jingyi, Ren Wenjie. Research progress on the distribution, migration and control of per- and polyfluoroalkyl substances in Chinese soils

3How to reduce the entry of perfluoroalkyl substances into the body?

In practice, things are much simpler. As you can probably tell from the name, “perfluorinated and polyfluoroalkyl substances” are hard to pronounce, let alone how to detect their pollution level from a professional perspective.

However, although we cannot decide to set industry testing standards and revise laws and regulations, we can at least decide where we are. For some factories that produce outdoor clothing, carpets and other products, you can choose to stay away from them as much as possible. Compared with ordinary people, practitioners in the above industries should pay more attention to protection, regular inspections, and only engage in production work under the premise of ensuring their own health.

Source | Pexels