There are two main types of plastic bags. A type of plastic called polyethylene. A plastic called polyvinyl chloride. PVC plastic is toxic and cannot be used for direct food packaging. Plastic bags for food can only be polyethylene plastic.
How do we distinguish between polyethylene plastics and PVC plastics in life? Let’s illustrate with two samples that we are more familiar with.
The shopping bags and fresh-keeping bags in the supermarket are polyethylene plastics, and the garbage bags are polyvinyl chloride plastics. These two kinds of plastic bags can be distinguished from three aspects.
First look at transparency. Good transparency, shiny is polyethylene plastic. The transparency is not good, and the dull one is PVC plastic.
The second look at density. Take a small piece of plastic bag and throw it into the water, the sink is PVC plastic. Floating on the water is polyethylene plastic.
The third burn smells. Those with pungent odor of hydrochloric acid are polyvinyl chloride plastics, and those without pungent odor of hydrochloric acid are polyethylene plastics.
Non-food plastic bags should never be used for food. Polyvinyl chloride is a strong carcinogen. Prolonged contact with the human body can also damage the nervous and blood systems. At about 50 degrees, polyvinyl chloride can decompose into hydrogen chloride gas. Therefore, using PVC plastic to pack hot food is more harmful.
Polyethylene plastic is non-toxic and can come into contact with food. The well-known fresh-keeping bags, food bags, mineral water bottles, etc. are all made of polyethylene.
Since polyethylene plastic is non-toxic, can we use it with confidence? If you do this, you are very wrong.
Plastic is a synthetic organic polymer compound. Such compounds were not previously found on Earth. All macroscopic organisms on earth have correspondingly evolved microorganisms that decompose it. After the macroscopic organisms die, they will be decomposed by microorganisms. Plastics have only been around for a hundred years. Microbes that can break down plastic have not yet evolved on Earth. Plastics are not degradable in nature.
Once the tiny particles of plastic enter the human body, they cannot be digested and absorbed. Of course, it cannot be excreted through the normal route. The latest research has found that tiny particles of plastic are detected in most people’s bodies. These microplastics enter the body through food, bottled water and even respiration.
What impact do these plastic particles entering the human body have on human health? There are no scientific studies yet. But one thing is certain, these microplastics are definitely not what the human body needs. Because human beings have not seen plastic in the evolutionary process of billions of years. The impact of plastic particles in the human body on human health remains to be further studied.
What we can do now is eat as little food as possible, drink less water from plastic bottles, and use less plastic of any kind. While plastic is convenient for us, it is also eroding our world.
Use less plastic, start with you and me, start now. Not only to protect you and me, but also to protect our earth.
I am Ah Quan. Chemistry teacher chats about life. Follow me if you like me.