Water is an important substance that makes up the body and plays an important physiological role, and drinking enough water is the foundation of good health, and can also help us maintain normal physical activity and cognitive ability.
We have a wide range of drinking water sources every day, tap water, bottled water, and bottled water can all be selected. Some people even prefer to choose bottled or bottled water because they are worried about the quality of tap water, is this choice really healthier?
What are the dangers of microplastics to the human body?
I don't know how many people have heard of microplastics? It is ubiquitous in our lives, and there has been a lot of research on microplastics in recent years. Microplastics are very small plastic particles with a length of 1 μm to 5 mm, and there are even nanoplastics, which are smaller than microplastics, only < 1 μm.
Compared with microplastics, nanoplastics are smaller in size and easier to travel through various tissues and organs in the human body, and can cross biological barriers (such as cell membranes) and enter biological systems, including blood, lymphatic system, and even the whole body, which is more harmful to human health.
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In life, we and microplastics can be said to "get along day and night", and there is a wide range of things that contain it, as long as it is made of plastic, it is almost inevitable that there will be microplastics. Not only that, but there may also be microplastic contamination in the bodies of marine organisms such as fish and shellfish, which can enter our bodies through ingestion. Diet is the main way humans consume microplastics, and it is estimated that each person eats about 5 grams of microplastics per week, which is equivalent to the weight of a bank card.
Many people may think that microplastics are foreign bodies, and even if they are eaten into the body, they should be excreted from the feces!
Some of the microplastics that are eaten are excreted in the stool, but some of them are still present in other organs and tissues of our body. Studies have found that there are an average of 20 microplastic particles per 10 grams of human feces. And scientists have successively found the presence of microplastics in colon specimens removed by humans, and even placental tissue. Scientists from Vrije Universiteit Amsterdam in the Netherlands have discovered the presence of microplastics in human blood for the first time. This suggests that microplastics may travel through the body with the bloodstream and affect various organs.
Don't underestimate the microplastics that are ingested into the body, they can affect the absorption of micronutrients, increase intestinal discomfort symptoms such as diarrhoea, rectal bleeding and abdominal cramps, and puncture and rub against organ walls to induce inflammation. At present, the impact of microplastics on human health is still unknown, and more needs to be explored.
The water I drink turned out to have microplastics
In January 2024, researchers from Columbia University in the United States published a new study in the international academic journal Proceedings of the National Academy of Sciences (PNAS).
For the first time, researchers used new optical imaging techniques to observe the presence of "nanoplastics/microplastics" in bottled water/bottled water, and found that each 1-liter bottle of bottled water contains about 240,000 microplastics, including 90% nanoplastics and 10% microplastic particles. In addition, bottled water will contain more microplastics in the water under the conditions of repeated switching and exposure to high temperatures.
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However, microplastics are not the only problem in bottled water, and tap water is also not immune to microplastic pollution. A study of 159 tap water samples from 14 countries around the world was analyzed, of which 129 contained nanoplastics/microplastics, a high detection rate of 81.1%.
In other words, whether it's bottled water or tap water, we ingest some microplastics when we drink water.
How to solve the problem of microplastics in water?
In fact, don't worry too much, for tap water, we only need to boil the water before drinking it to minimize the microplastics entering the human body and reduce their harm to the body.
In February 2024, a joint study from Guangzhou Medical University and Jinan University found that boiling hard water and then simply filtering it can remove more than 80% of nanoplastics/microplastics in the water.
The study also found that the removal rate of microplastics in water increased gradually with the gradual increase of water temperature during the boiling process, and the higher the hardness of water, the better the removal effect of microplastics in water. This is because the boiling process allows the microplastics to co-precipitate with certain compounds in the water, which can easily be encapsulated by limescale and precipitate at the bottom of the container, resulting in better removal.
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Based on global water quality and differences in water use habits, the researchers estimated the intake of nanoplastics/microplastics by adults and children drinking boiled and tap water in 67 regions across six continents. The results showed that compared with drinking tap water every day, the intake of nanoplastics/microplastics in boiled water after drinking boiled water was reduced by 2~5 times compared with the former.
"Drinking more hot water" is a traditional way of health care for mainland residents, which not only makes it comfortable, but also plays a role in "purifying" water, helping us reduce the intake of microplastics, which is more beneficial to health. At the same time, it is also recommended that everyone boil the water to settle for a period of time, do not drink the rest of the water bottom, and use filtration devices, such as installing filters for tap water, using cups with strainers, etc.
Tips to reduce your intake of microplastics
Since microplastics are harmful to health, in addition to boiling water before drinking, it is also recommended to do the following things.
1. Eat less plastic packaging takeaway, and don't eat directly in plastic bags
Most takeaways are packed in plastic boxes or bags, which may cause us to ingest more microplastics.
Don't put plastic bags of spicy hot, rice noodles and other foods directly on the bowl to eat, the high temperature will make microplastics more dissolved in the food, after receiving the takeaway, you should pour the food into your own tableware as soon as possible. Also, eat less food packaged in plastic packaging.
2. Use less plastic cutting boards
Researchers cut carrots on polypropylene cutting boards and polyethylene cutting boards to evaluate the total amount of microplastics exposed to the average person when using the two types of plastic cutting boards.
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The results showed that both carrots were contaminated with microplastics, and more microplastics were shed during the process of cutting food with a knife. Researchers estimate that a person may be exposed to 14.5 million ~ 71.9 million polyethylene microplastics per year if a plastic cutting board is used, while polypropylene microplastics are about 79.4 million.
3. Don't eat seafood offal
Microplastics can enter the bodies of some marine organisms and contaminate fish and shellfish food.
Researchers from the Hull York School of Medicine at the University of Hull in the United Kingdom systematically analysed more than 50 studies between 2014 and 2020 to investigate the level of microplastic pollution in marine life worldwide. It was found that the microplastic pollution of molluscs in the coastal areas of Asia was the most serious, which existed in the intestines and livers of marine animals, among which mussels, oysters and scallops had the highest microplastic content.
Therefore, when eating aquatic products, first of all, do not eat them raw, they must be cooked thoroughly, and secondly, they should remove their stomach and intestines, internal organs and gills.
4. Drink less milk tea and use less plastic straws
Drinks or foods with high temperatures will release more microplastics, including but not limited to hot coffee, hot milk tea and other drinks, and many people are also accustomed to using plastic straws to drink drinks, which will also increase the intake of microplastics.
5. Try not to use the nonstick pan again after scratches
A 2022 study published in Whole Environment Science mentions that a few millimeters of scratches in nonstick pans can release large amounts of microplastics. A broken coating can result in the release of 2,300,000 microplastics and nanoplastics, and surface cracks may leave around 9,100 plastic particles.
The non-stick coating for most nonstick pans is usually polytetrafluoroethylene, also known as Teflon, which is a synthetic plastic. When there is strong abrasion between the surface of the cookware and the hard object, tiny PTFE particles may form, which can then contaminate the food and be ingested by humans.
Therefore, it is best not to use a non-stick pan after it has been scratched, and do not use a non-stick pan to cook hard foods, such as ribs, without using a sharp spatula, and replace the pan with a new one regularly.
bibliography
[1] Cox KD, Covernton GA, Davies HL, Dower JF, Juanes F, Dudas SE. Human Consumption of Microplastics. Environ Sci Technol. 2019 Jun 18; 53(12):7068-7074. doi: 10.1021/acs.est.9b01517. Epub 2019 Jun 5. Erratum in: Environ Sci Technol. 2020 Sep 1; 54(17):10974. PMID: 31184127.
[2] Leslie HA, van Velzen MJM, Brandsma SH, Vethaak AD, Garcia-Vallejo JJ, Lamoree MH. Discovery and quantification of plastic particle pollution in human blood. Environ Int. 2022 May;163:107199. doi: 10.1016/j.envint.2022.107199. Epub 2022 Mar 24. PMID: 35367073.
[3] Qian, Naixin et al. “Rapid single-particle chemical imaging of nanoplastics by SRS microscopy.” Proceedings of the National Academy of Sciences of the United States of America vol. 121,3 (2024): e2300582121. doi:10.1073/pnas.2300582121
[4] Naixin Qian, Xin Gao, Xiaoqi Lang, Huiping Deng, Teodora Maria Bratu, Qixuan Chen, Phoebe Stapleton, Beizhan Yan, and Wei Min. "Rapid single-particle chemical imaging of nanoplastics by SRS microscopy." PNAS. 2024.
[5] Yadav, Himani et al. “Cutting Boards: An Overlooked Source of Microplastics in Human Food?.” Environmental science & technology vol. 57,22 (2023): 8225-8235. doi:10.1021/acs.est.3c00924
[6] Danopoulos, Evangelos et al. “Microplastic Contamination of Seafood Intended for Human Consumption: A Systematic Review and Meta-Analysis.” Environmental health perspectives vol. 128,12 (2020): 126002. doi:10.1289/EHP7171
[7] Luo, Yunlong et al. “Raman imaging for the identification of Teflon microplastics and nanoplastics released from non-stick cookware.” The Science of the total environment vol. 851,Pt 2 (2022): 158293. doi:10.1016/j.scitotenv.2022.158293
Planning and production
Source丨Popular Science China
Author丨Xue Qingxin is a registered dietitian
Audit丨Liu Lu is a professor and doctoral supervisor of the School of Chemistry and Molecular Engineering, East China Normal University
Planning丨Fu Sijia
Editor丨Fu Sijia
Reviewer丨Xu Lai, Lin Lin
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