Man uses science to create an "eternal" material, uses it and then wants to throw it away. But for now that seems impossible, every piece of plastic ever created is still with us.
When we were kids, we were often warned "don't swallow gum because it sticks to your intestines." Of course, we later learned that swallowed gum leaves your body in your poop.
The base of many modern gums is made of synthetic rubber, and gum is also known to contain plastic. Plastic does not digest, eat "through the intestines", just pull out. But it's not as simple as that. While plastic bags or water bottles in the environment can break down to the point where they're no longer an eyesore, tiny pieces can still be ingested by animals and humans. In fact, microplastics have already been found in fish and mammals, and now, new research has found that microplastics are ubiquitous, as well as in the human placenta.
Microplastics found in human placenta for the first time
On October 23, 2018, researchers at the Medical University of Vienna announced that the presence of microplastics in human feces has been detected, making it an established fact that microplastics enter the human gastrointestinal tract. A survey of microplastics in the faeces of young people in Beijing also found that microplastics were prevalent in the subjects' faeces.
In August 2020, at the annual meeting of the American Chemical Society, an even more surprising discovery was made: microplastics were detected in human lung, liver, spleen and kidney tissue samples. The finding confirms that microplastics don't just linger in the digestive system, but also "infiltrate" into other tissues. What was not expected was that the infiltrated tissue also contained the human placenta.
In January 2021, a study published in Environment International provided "hard evidence" that plastic has "taken over" the human placenta. Researchers analyzed the six 18 and 40 normal healthy pregnant women of the placenta, four of six placenta there discovered the existence of the micro plastic, 12 were detected spherical or irregular small pieces of plastic, size between 5 ~ 10 microns (similar to red blood cell size), five particles located in placenta part connected to the fetus, Four particles are in the area connected to the mother's uterus and three are in the cell membrane surrounding the fetus. Of the 12 fragments, three were clearly identified as polypropylene (the material used to make plastic bottles and caps), while the remaining nine were identified as paint-like materials that could come from fragments of cosmetics, nail polish, toothpaste, creams, body creams, adhesives and more. The study was approved by an ethics committee and the placentas were collected using a method that ensured they did not come into contact with any plastic utensils or tools from the outside world.
These studies reveal that microplastics are not only found in the environment, but also in the human body. How do these microplastics get into the human body and how harmful are they to health?
Multiple routes into the body
Microplastics are small and mostly invisible, but that doesn't stop them from lurking around us. Simply put, as soon as we breathe and eat, microplastics find their way into our bodies.
In May 2019, WWF commissioned the University of Newcastle in Australia to estimate how much microplastics humans ingest from nature. After analyzing and synthesizing the existing literature on human plastic consumption, the researchers estimated that the average person ingested about 2,000 tiny plastic particles per week, equivalent to the weight of a credit card. These tiny particles can come from a variety of sources, including synthetic clothing fibers, beads in toothpaste or cleanser, or the breakdown of larger plastic sheets.
Of the 52 studies calculated by Newcastle University, 33 looked at plastic consumption in food and drink. The studies highlighted a range of common foods and drinks that contain microplastics, such as drinking water, beer, shellfish and salt. Water is the largest source of microplastics, with the average person consuming 1,769 pieces of plastic a week just by drinking from a bottle or tap. Shellfish are the second largest source of plastic intake, with the average person ingesting up to 182 particles (0.5g) per week.
The third way plastic enters the body is through inhalation. The study looked at 16 papers on outdoor and indoor air quality. The results show that plastic pollution in indoor air is more serious than that in outdoor air. This is because indoor air circulation is limited, and synthetic textiles and household dust are among the most important sources of microplastics in the air. This estimate is very conservative, but hints at the fact that exposure to microplastics in the air may depend largely on local conditions and lifestyle.
In addition to air inhalation and regular dietary intake, there are more unexpected ways in which human cognition is being eroded.
In 2019, Canadian chemical engineer Nathalie Tufenkji discovered the harsh truth about tea bags: tea bags = drinking plastic! They will choose and buy any of four brands of tea bags (two is nylon material, is PET material) soaked in hot water after 5 minutes, found that billions of plastic found in tea, there are 11.6 billion of the 3.1 billion micro plastic particles and nanometer micro plastic particles, also detects a small amount of heavy metal material such as arsenic, aluminum, lead and chromium.
An October 2020 study tested 10 polypropylene milk bottles, which account for two-thirds of the global milk bottle market, and found a strong correlation between temperature and microplastic release during formula brewing. Warmer liquids (formula or water used to sterilize baby bottles) cause more microplastics to be released. Each liter of liquid heated in polypropylene bottles releases between 1.3 million and 16 million microplastics and trillions of smaller nanoplastics, according to the data. Other polypropylene plastic products (kettles, lunch boxes) also release similar levels of microplastic particles.
The team also conducted a global survey and estimated the exposure of 12-month-old infants to microplastics in 48 regions. Under current guidelines for bottle disinfection and feeding formula preparation, infants are exposed to an average of more than 1 million microplastics per day. Oceania, North America and Europe had the highest levels of potential exposure, with 2.1 million, 2.28 million and 2.61 million microplastics per day, respectively.
These numbers may seem alarming, but scientists still say that due to methodological and data limitations, the amount of plastic consumed by humans may be underestimated.
How much harm
While human knowledge of the effects of microplastics on Marine and freshwater organisms and ecosystems is expanding, there is still a significant knowledge gap in the understanding of how exposure to microplastics may affect human health.
In a 1998 paper published in Cancer Epidemiol Biomarkers Prevention, researchers discovered cellulose and plastic fibers in human lungs. Lung cancer and non-neoplastic lung tissue samples were obtained from patients who had lung tumors resected. Using a laminar flow mask to block the contamination of foreign fibers and plastics, the scientists found that heterogeneous fibers were repeatedly observed in the fresh lung tissue. Examination of pathological sections of lung tissue with polarized light revealed that these inhaled heterogeneous fibers were cellulose and plastic fibers. The researchers hypothesized that the microplastics inhaled into the lungs may have originated in the air.
Plastics are inert. To increase their flexibility, hardness, and heat resistance, and to make plastics more colorful, many industrial and daily products made with plastics contain hormone-disrupting Chemicals, EDCs), which can have long-term effects on human health.
It is conservatively estimated that more than 1,000 EDCs are currently in use. Known endocrine disruptors that leach out of plastics and threaten health include bisphenol A (BPA), flame retardants, phthalates, uv stabilizers and toxic metals such as lead and cadmium. Edcs-containing plastics are widely used in construction, flooring, food packaging, cooking utensils, children's toys, leisure goods, furniture, household appliances, textiles, automobiles and cosmetics. A report published in 2020 by the International Endocrine Society revealed that many of the plastics we use every day at home and at work expose us to a harmful cocktail of endocrine-disrupting chemicals.
EDCs "escape" from microplastics and become exposed to people. In the whole life cycle of plastic products, the contact between EDCs and human body is widespread. And tests on human samples consistently show EDCs in almost all of those tested. They can also bind and accumulate toxic chemicals in the environment around them, such as seawater and sediment, acting as carriers of toxic compounds.
In 2019, Peking University researchers studied estimates of the disease burden caused by exposure to phthalates in three diseases in the Chinese general population: male infertility, adult obesity and diabetes. In 2010 alone, there were about 2.5 million cases of male infertility, adult obesity and diabetes caused by exposure to phthalate chemicals in China, and the medical cost was about 57.2 billion yuan. Among them, phthalates have the most significant effect on male infertility, followed by adult obesity and diabetes.
As plastic production and use has increased, so has human exposure to plastic. Due to the complexity of microplastics, we still know very little about their journey through the environment and their effects on organisms and ecosystems, and further research is needed to determine the distribution patterns of microplastics in the environment and their effects on human health.