Microplastics found in human blood, how do they invade our bodies?

Review expert: Zhou Jiaojiao, Associate Professor, School of Food Science and Engineering, Wuhan University of Technology

Some time ago, the editor saw such a news on the Internet: "Environment International", an authoritative journal in the field of environmental science, published an article introducing that a Dutch research team discovered microplastics in human blood for the first time.

Source: sciencedirect.com

In this study, researchers detected the components of microplastics through blood analysis of 22 volunteers. They also found that most of these microplastics came from daily necessities. The main components include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), etc., among which PE and PET accounted for 23% and 50% respectively.

Invisible microplastics

Microplastics, as the name suggests, are tiny plastics. Compared with ordinary plastics, microplastics are more easily degraded and more likely to flow and migrate in the environment. They are a new type of environmental pollutant. In 2004, Richard Thompson, a scientist at the University of Plymouth in the UK, first proposed the concept of "microplastics" in the magazine "Science". Microplastics are generally considered to be plastic fragments with a diameter of less than 5mm, including plastic fibers, films, particles, etc.

It is estimated that the global annual production of plastics is 300 million tons, and about 10% of plastics will eventually enter the environment. These plastic wastes will eventually form microplastics through physical, chemical and biological reactions. In addition, the emission of plastic microspheres or fibers in cosmetics, cleaning products and textiles is also an important source of microplastics.

Source: The Guardian

In 2016, the United Nations Environment Programme published a global environmental report stating that microplastics are becoming more widespread and increasing in number, and that they can even be detected in the deep seabed thousands of meters deep. In 2022, a study published in the scientific journal The Cryosphere showed that microplastics were also found in the uninhabited Antarctic ice and snow.

So, where do microplastics come from?

There are two main sources of microplastics. One is the industrial manufacturing of daily necessities. Degraded fragments produced in the process of manufacturing water-soluble chemical products such as shampoo and laundry detergent are discharged into rivers, lakes and seas after being treated by wastewater treatment plants. The other is the treatment of other large plastic waste. Microplastics generated after plastic waste is disassembled and fragmented by biological, physical and chemical means are easily transported through water sources and eventually enter the sea.

Source: Baidu Encyclopedia

Microplastics are not indegradable, but the process is very slow, and during the degradation process, they will interact with other substances in nature and even life forms. For example, due to their high specific surface area and hydrophobicity, microplastics are easy to absorb pollutants such as heavy metals, polycyclic aromatic hydrocarbons and bisphenol A, and can enrich various heavy metals and other pollutants in the environment, promote the aggregation and precipitation of pollutants, and accelerate environmental pollution.

Nowadays, the impact of microplastics on nature has also extended to humans. Some people may wonder, since microplastics are small in size, are they very harmful to the human body? The answer is yes.

Impact of microplastics

Every year, about 3% of the plastic waste produced by humans enters the ocean. Some of these plastics are ingested by marine organisms, causing intestinal obstruction and pathological damage to marine organisms; some of them are attached to microorganisms and sink to the bottom of the sea, becoming deep-sea sediments. After being digested, decomposed, and degraded by organisms, microplastics accumulate step by step along the food chain and are eventually passed on to humans at the top of the food chain.

Source: unsplash

The impact of microplastics on the human body is reflected in many aspects. Microplastics are small in size and will reach various organs throughout the body through the human circulatory system, causing cell damage, wearing out the inner walls of the digestive tract and other parts of the body, and inducing inflammatory responses.

Studies have shown that the human placenta is permeable to polystyrene and polypropylene microplastics of 50, 80 and 240 nm. For pregnant women, microplastics may also be passed to the fetus through the placenta during the breeding process, causing the immune system of the young to react and affect physical health. The American Endocrine Society and the International Pollutant Elimination Network have published a report stating that the chemicals contained in plastics can disrupt the human endocrine system and cause serious diseases such as reproductive disorders, diabetes and even cancer.

Microplastics are so harmful to the human body. How can we identify them in our daily lives so that we can "eat" less plastic?

How to identify microplastics?

Plastic products are very common in our daily lives. In addition to these "visible" plastics, there are also many "invisible" plastics that we need to pay attention to. According to the paper "Human Consumption of Microplastics", humans ingest about 30,000 to 50,000 microplastics each year, and those who love to drink bottled water on a daily basis ingest up to 210,000. In 2022, a research team from Nanjing University investigated stool samples from multiple provinces and cities and found that participants who often drank bottled water and ate takeout had higher levels of microplastics in their feces.

Source: China Biotechnology Network

So how do you identify plastic products from their packaging? You can tell them apart from the outer packaging logo. In the field of plastic products, there is an SPI logo scheme that sets classification codes for plastic products. The logos of several types of plastic materials that we often come into contact with in our daily lives are PET/PE/PP/PS/PVC/PC . If you see these logos on the outer packaging of a product, it means it is made of plastic.

Plastic product classification code

Source: SPI Classification Standard, Guolian Securities Research Institute

In addition, the surface of the cups of takeaway drinks we order daily are also coated with polyethylene (PE), which may be ingested by the human body after degradation; and seafood - microplastics enter the sea, pollute the water, and are ingested by fish and shrimp. When humans catch these seafood and eat them, the microplastics also enter the human body.

Microplastics swallowed by fish

Source: ifeng.com

Seeing this, you may be surprised. There are microplastics everywhere in life. How can we avoid them? Indeed, it is difficult to completely avoid contact with microplastics at present. For individuals, the only way to reduce the intake of microplastics is to reduce the use of plastic products from the source. In daily life, we can use less disposable plastic products, such as plastic straws, disposable cups, plastic bags, plastic boxes, etc. If you must use them, please be sure to buy them from regular manufacturers.

Source: pexels

Secondly, in terms of diet, do not eat wild animal and plant food from polluted waters, and choose to buy aquatic products from regular sources; in addition, we can also insist on garbage classification, promote the recycling of plastic waste, and use our own small actions to subtly influence more people. In recent years, as people's environmental awareness continues to increase, many beverage stores have also introduced environmental protection measures such as bringing your own cups and degradable straws, and many stores have also introduced the purchase and use of environmentally friendly bags...

Source: unsplash

"Environmental protection" is not only our social responsibility, but should also become our attitude towards life. Everyone's every move can make the world a better place. Practicing environmental protection starts with you and me.