Whenever you heat food in the microwave, hundreds of millions of microplastics are released from the plastic container and mixed into your food. These particles can enter your bloodstream and organs, posing a potential health threat.
This issue is important because its impact is not limited to individuals, but even to the social environment as a whole. So, how are these particles created? What are their effects on human health? And how can we effectively reduce their pollution?
How many of these particles will be produced by microwaving food? We can look at the latest scientific research.
The study was conducted by Professor Li Jianguo and his team from the Research Center for Eco-Environmental Sciences, Chinese Academy of SciencesIn 2023, they published a paper titled "Plastic Containers in Microwave Ovens Release Microplastics and Nanoplastics".
In this article, they experimented with four commonly available plastic containers, including polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS).
They filled these plastic containers with water and heated them in a microwave oven to simulate people using microwave ovens in their homes and offices.
Subsequently, they analyzed the heated water samples using instruments such as high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS MS) and scanning electron microscopy (SEM).The number and characteristics of the plastic particles in it are calculated by detection.
They found thatThe microwave-heated water sample contains a large amount of microplastics and nanoplastics, while the number and characteristics of plastic particles released by different types of plastic containers also vary.
Among them, PP containers release the largest number of plastic particles, up to 4.2 million microplastics per square centimeterThere are as many as 1.2 billion nanoplastics. These plastic particles range in size from a few microns to hundreds of nanometers and take different shapes.
It may be difficult for you to imagine how tiny these plastic particles are, so we can use some analogies to help you understand. The diameter of a microplastic is about 0001 mm, which is one-tenth of the thickness of a hair; Whereas the diameter of a nanoplastic is about 00001 mm, which is one thousandth of a hair.
If you fill a PP container with water and heat it in the microwave, then the equivalent is that you add a grain of plastic pellets the size of a grain of rice to the water. If you do this every day, you'll be ingesting nearly a kilogram of plastic over the course of a year.
So, why does microwave heating cause plastic containers to release plastic particles? This is because microwave ovens work by using microwaves to stimulate the vibrations of water molecules, which produce heat.
When water molecules are heated,They can create pressure and friction on the plastic container, causing it to crack and peel off, thus forming plastic particles. Moreover, different types of plastic containers have different materials and processes, some are more resistant to high temperatures, others are more brittle, so the number and characteristics of the plastic particles released will also vary.
Experimental evidence shows that these particles are not digested and excreted by the body, but accumulate insideCauses damage to various organs.
A research team led by Professor Scott Malcolm of the University of California, San Diego, a member of the National Academy of Sciences, has discovered the migration of plastic particles inside the human body.
They fed fluorescently labeled plastic pellets to miceThe various organs of the mice were observed using a fluorescence microscope. The results showed that the plastic particles were not only present in the intestines of mice, but also entered various organs of mice through blood and lymph.
In addition, the number and location of plastic particles vary over time, suggesting that they have a dynamic migration and accumulation process in the human body.
Another study, led by Professor Tammy Goldsmith of the University of Exeter in the United Kingdom, revealed the potential harm of plastic particles to human health.
They treated kidney cells from human embryos with different concentrations of plastic particlesand evaluated the effects of plastic particles on cells by methods such as cell viability assay and apoptosis assay.
The results showed that high concentrations of plastic particles could cause kidney cell death in human embryos, while low concentrations of plastic particles could interfere with the normal function of cellsFor example, it affects the metabolism, proliferation, and differentiation of cells. These findings suggest that plastic particles can cause serious damage to human physiological functions.
In addition, there is some indirect evidence that plastic particles may trigger or exacerbate some common diseases. For example, some studies have found that:Plastic pellets contain some harmful chemicals, such as bisphenol A (BPA), phthalates (PAES), etc.
These chemicals can be dissolved from plastic particles, enter the body's blood and tissues, interfere with the body's hormone secretion, and affect the body's fertility, immunity, cognitive ability, etc.
Despite these findings,But why hasn't the impact of plastic particles on human health been given enough attention? This is mainly because there are still some limitations in the current research on plastic particles.
First of all, the detection and analysis methods of plastic particles are not perfect, and different research institutions may use different parameters, which affects the comparability of results.
Secondly, the toxicology and ecology of plastic particles are not well studied, and many studies are only conducted in vitro or animal models, and there is a lack of direct human studies, so the long-term comprehensive effects of plastic particles on human health cannot be accurately inferred.
Finally, social policy research on plastic particles is not effective enoughMany countries have yet to develop and implement regulatory standards for plastic pelletsIt is difficult to effectively control the spread of plastic particles.
First of all,Try to avoid using plastic containers to heat food in the microwave, instead opt for safer materials such as glass or ceramic. These materials do not release plastic particles, are more environmentally friendly and easy to clean and reuse. If glass or ceramic containers are not available, food can be wrapped in paper towels or wax paperAvoid contamination by plastic particles.
Secondly, if plastic containers must be used,The release of plastic particles can be reduced by adjusting the heating time and temperature. The shorter the heating time and the lower the temperature, the less plastic particles are released.
In addition, cutting food into small pieces, serving in large bowls, and pouring out food before heating can also reduce the contact area between food and plastic containers, thereby reducing contamination.
Finally, it is also important to choose high-quality and safe plastic containers. Look at the label when purchasing, choose products that meet quality standards, and avoid inferior products. Choosing new plastic containers that are resistant to high temperatures, environmentally friendly, and easy to degrade, and regularly replacing and cleaning plastic containers are also effective ways to reduce pollution.
As individuals, we can minimize the use of plastic containers in microwave heating by changing our lifestyle habitsChoose safer, more environmentally friendly ways to store and heat food.
At the same time, as a society, China and related institutions should also strengthen the supervision of plastic particle pollution, promote the innovation of plastic industry technology, develop safer and more environmentally friendly alternative materials, formulate stricter laws and regulations, and promote social attention to the problem of plastic particles.