It is undeniable that scientific and technological civilization has brought unprecedented comfort and convenience to human life. We used science to conquer and transform nature, and now human beings seem to be above nature.
But let's not forget that human beings are actually part of nature. When we conquer nature, we are actually conquering ourselves with scientific weapons, and the ultimate bitter fruit will still be borne by human beings.
Take plastics as an example. Indeed, this material is the greatest invention since the industrial age of mankind and the product of human wisdom. As soon as it appeared, it quickly occupied all aspects of human life with its advantages of cheapness, high strength, corrosion resistance and strong plasticity.
Nowadays, plastic products can be said to be everywhere in our lives. If you look around, you will find that you are surrounded by plastic.
Even the clothes you are wearing now are made of recycled plastic bottles (PE), that is, polyester fiber, which we affectionately call polyester.
We can't live without plastic now. The same plastic is now eating back at the earth and threatening mankind. It occupied every corner of the earth at lightning speed.
In the 1950s, the world produced only a few million tons of plastic every year, but today, China alone produces more than 30 million tons of plastic every year, and the world produces more than 330 million tons every year.
So where did these big plastics go?
It is no exaggeration to say that 1/3 of the plastic has entered the ocean and been brought to all parts of the world with ocean currents. Only a small part is recycled and made into secondary products (polyester fiber clothes), and most of the rest are buried in the ground or discarded everywhere at will, forming terrible white pollution.
Some of these plastic products are used for several minutes, such as plastic bags, disposable plastic cups, straws and so on. But it takes hundreds of years for the earth to digest them, and some plastics take thousands or even tens of thousands of years to completely decompose.
According to the increasing plastic production of human beings and the time it takes for the earth to digest plastic, in the long run, the earth will definitely become a planet whose surface is completely covered with plastic.
At that time, serious white pollution will make the earth no longer suitable for any life.
However, the harm of plastics is not so simple. In the process of being decomposed by nature, plastics will form microplastics. The diameter of these microplastics is less than 5 mm, even reaching the level of micron or nanometer; The shapes are particles, fibers and films.
These microplastics are a real threat to life. Now they are all over the world. There are decomposed microplastics in land soil, fresh water system and places with plastic waste. These microplastics will enter the animals and then enter the human table again.
Even the air we breathe has fallen plastic fibers, which come from daily necessities such as polyester clothes and blankets.
There are also some plastic tableware, such as cups and mineral water bottles, which we usually use. Whether it is PE or PP, millions of microplastics will fall off after encountering high temperature.
According to a paper published in the journal Nature and Food, the plastic bottles made of PP used by babies will lose 55 million plastic particles per liter of water after encountering high temperature (95 degrees Celsius).
PP material is the plastic used in most baby bottles. It is non-toxic, but it will shed particles and eventually enter the baby.
So the next time we mix milk powder, don't mix it too high or directly in the bottle. We can mix them in non-plastic containers in advance, let them cool, and then pour them into bottles. Remember not to shake it.
Or you can choose glass bottles directly if you are not at ease.
So now plastic particles have flooded human life, and outside the circle of human life, plastic particles also exist in large quantities.
For example, this year, scientists analyzed the 1 meter-long ice core (kept in the laboratory) taken out in the Antarctic in 2009, and found 96 plastic particles in it.
The arctic is more serious. In a sample collected near a country road in Bavaria, scientists found that there were 65,438+054,000 plastic particles per liter, and the snow in the Arctic contained more than 65,438+044,000 plastic particles per liter.
It can be seen that human activities in the Arctic are more frequent and plastic pollution is more serious.
Neither pole of the earth has escaped plastic pollution, so where else is remote? You may think of Mount Everest. Unfortunately, it was conquered by humans at 1953.
Recently, scientists collected 19 samples on Mount Qomolangma at 8000m and 8440m respectively. In the samples, scientists have detected the existence of microplastics.
The 8000m sample contains 79 microplastics per liter of snow, and the 8440m sample contains 12 plastic particles on average.
As for the origins of these microplastics, scientists believe that some of them were brought up by climbers, and some microplastics were carried to high places by air currents.
But in any case, with the addition of Mount Everest, it can be said that the earth is now completely occupied by plastic.
The study was found in an Earth magazine.
So what harm does microplastics do to human body?
In fact, there are not many studies on the hazards of microplastics, because there are no specific cases for us to study. At present, we only know that particles with a diameter exceeding 150 micron will be excreted with human feces.
This study was published in ACP Journal 20 19. Scientists have detected plastic particles in human feces, with a maximum diameter of 500 microns.
This study confirms the fact that microplastics has entered the human body. But what kind of danger is not clear.
However, scientists speculate that plastic particles less than 20 microns in diameter cannot be excreted by metabolism after entering the human body. They will enter the blood and various internal organs of the human body and accumulate continuously. If it reaches a certain amount, it will definitely lead to various unknown risks.
Those particles with the smallest diameter can even enter the cells of human body and accumulate in the cells, affecting the function of cells.
However, with the increasing harm of microplastics to human beings, there may be some cases related to microplastics in the future, so scientists can specifically study what harm these microplastics will do to people.
Therefore, once again, human beings are actually trapped step by step while facilitating themselves and conquering nature. We can never get rid of nature, so we can't conquer it. We should learn to live in harmony with nature, protect nature and cherish the earth.
We should use less plastic products in our daily life, go out to get cloth bags and vegetable baskets, and leave a healthy earth for our future generations.