Ecological environment examples

If the emergence of infectious diseases is closely related to the environment and ecology, people may not think of the relationship.

The University of Hong Kong discovered that the coronavirus in the masked civet (commonly known as the civet) is related to causing SARS in humans. Prior to this, the "Nipah virus" in Malaysia, the "West Nile virus" in New York, and even the "bird flu H5N1 virus" in Hong Kong all came from animals, and were related to environmental damage, global warming and the distance between humans and animals. The factors that are too close are inseparable.

In addition to keeping your home clean, to prevent the emergence and spread of infectious diseases, you must also look beyond and protect the environment.

The impact of SARS in Hong Kong has been rare in recent years. Although the "bird flu" broke out in 1997, due to the timely killing of chickens, the maintenance of market cleaning days, and the vaccination of chickens, the impact of this infectious disease has gradually faded in the hearts of Hong Kong people. go. But looking around, we can see that the threat of infectious diseases has never stopped. It just doesn’t happen in Hong Kong and Hong Kong people don’t pay attention.

Ecological changes, viruses spread from person to person

In advanced countries such as the United States, the "West Nile Virus" has broken out since 1999. According to the website of the U.S. Centers for Disease Control and Prevention (CDC), the virus itself has long existed in birds (in other words, birds are the host of West Nile virus). After a mosquito bites a bird carrying the virus, The virus remains in their salivary glands and can be spread by biting other birds and humans.

Lao Wing-lok, President of the Hong Kong Medical Association, pointed out that the environment and human diseases are closely related. Another animal-related infectious disease is caused by the Nipah Virus. Since 1998, cases have appeared in Malaysia and Singapore.

It itself existed in bats in the forest, and was later passed to pigs, and then from pigs to humans. Tracing back to its roots, it all started with forest fires. Bats that originally inhabited Sabah, East Malaysia, escaped due to forest fires and flew from East Malaysia to Peninsular Malaysia, West Malaysia, infecting pigs and humans in pig farms. If there had not been the fire in East Malaysia, the pigs would not have been infected.

He said that the fire was related to the very dry weather that year, and the abnormal weather was affected by El Ni?o. It can be seen that infectious diseases are indeed closely related to the environment and ecology. Moreover, the rise in global temperature is conducive to the reproduction of mosquitoes, which is also conducive to the spread of dengue fever; the rise in sea water temperature promotes the growth of plankton in the water, and the cholera bacteria that rely on them are transferred to these seafood because they eat plankton. People do not take good care of them. If you cook it and eat it, you will get cholera. This was the reason for the cholera outbreak in Hong Kong a few years ago.

As for the notorious "Ebola Virus", Lao Yongle said that because people cut down trees, they destroyed the homes of apes that originally lived in the forest, forcing them to interact with humans. Arise from contact.

Killing animals, destroying habitats and spreading viruses

In an interview with mainland media, Mao Jiangsen, an academician and virologist at the Chinese Academy of Sciences, said that many wild animals contain a large number of viruses, regardless of whether they are hunted or domesticated. , used for experimental purposes, have caused viruses that were originally only found in animals to invade humans. Ebola virus, HIV and yellow fever have little impact on their host apes, and the fatality rate is very low. However, humans have destroyed their habitats and expanded their range of activities to virgin forests. The viruses are transmitted to humans. The fatality rate on the body is very high.

The examples of Nipah virus, dengue fever, cholera and Ebola virus, etc., illustrate that if people fail to protect the natural environment and ecology, they will bring unexpected disasters - infectious diseases.

The SARS virus is related to civet cats. As for whether it is transmitted to humans, it has not been fully confirmed at the time of writing. Lao Yongle pointed out that a large dam was built at the source of one of the rivers in Guangdong Province where early cases of SARS occurred. Usually when a dam is built, the water level rises, and when people move away, so do the animals. He believes that it is worth investigating whether this will force animals to leave their original habitat and increase the chances of contact with people. People will catch and eat them after seeing them, and then spread the coronavirus in them.

Protect the environment and prevent the spread of infectious diseases

Lao Yongle said that in order to prevent the occurrence of infectious diseases, we must pay attention to reducing the greenhouse effect and reducing the rise in sea water temperature in the big picture, and pay attention to our own living conditions in the small part. Environment, care for the environment, protect the woods, take a multi-pronged approach.

When SARS did not appear, no one realized that infectious diseases still posed a threat to modern areas such as Hong Kong.

Lao Yongle said that compared with before, children are well-nourished and the immunization program is implemented. Even if they contract measles, its lethality has been reduced a lot; water sources are sufficient and clean, which has reduced the prevalence of cholera. . Infectious diseases are gradually being ignored, and the focus of the medical community has shifted to chronic diseases such as heart disease and cancer. The planning of wards is also focused on "large rooms". However, for infectious diseases, it will increase the risk of cross-infection.

"With SARS, other infectious diseases will also appear." Lao Yongle said that it is time to prepare for this.

(1) The atmospheric environment is deteriorating.

The main manifestations are: increase and intensification of climate disasters, global warming, melting of glaciers, corresponding rise in sea level, coastal lowlands are threatened by seawater inundation; changes in atmospheric composition that are not conducive to humans, increase in carbon dioxide, and the concentration of the ozone layer that alleviates ultraviolet radiation The hole in the ozone layer above the earth's two poles is getting bigger and bigger, and a variety of ingredients harmful to humans are also increasing. According to a 1997 report by the Ridge National Laboratory in the United States, the concentration of carbon dioxide in the atmosphere has increased by 30% since the industrial revolution, methane has doubled, and nitrogen oxides have increased by 15%. Carbon dioxide, methane, and nitrogen oxides are all gases that can produce a greenhouse effect, and an increase in their concentration causes temperatures to rise.

These changes in the atmosphere have natural causes. Volcanic eruptions and forest fires can send pollutants into the atmosphere. However, human use of fossil fuels such as coal and oil releases carbon dioxide, methane, nitrogen oxides, sulfur dioxide and other harmful gases and dust, which pollutes the atmosphere more seriously. Burning coal produces the most pollutants. The resulting poisonous fog and acid rain are outstanding manifestations of air pollution. The "murderous smog" first appeared in Belgium in 1930, and enveloped London four times from 1948 to 1962. The concentration of sulfur dioxide and dust in the smog far exceeded what people could bear, causing a total of more than 6,000 deaths. Although such records are rare, polluted air generally fills the spaces of many industrial and mining areas and cities.

Ordinary rainwater often contains trace amounts of carbonic acid. The polluted atmosphere has increased components such as sulfur dioxide and nitrogen oxides, making the rainwater more acidic. Now people define rainwater with a pH value lower than 5.6 as Acid rain. It looks like ordinary rainwater, but the acidic substances contained in it enter the soil and water on the land surface. The organisms that rely on these water and soil for survival are adversely affected, especially the destruction of forests. The pH first recorded as acid rain was 5.9 in 1939 (the pH of pure water is 7). By the 1950s, the pH value of acid rain had dropped to 3-5, with a record low of 2.1, which is about as acidic as vinegar or even more acidic. It shows that with the development of industry, the air is becoming more and more polluted. Since the atmosphere containing pollutants is flowing, it can travel across the ocean. The acidic components emitted by Japan can travel to the United States and form acid rain. It is not surprising that the acid rain in Canada originates from the United States. Scientists have determined that two-thirds of the sulfur dioxide gas gathering over Sweden and Norway comes from industrial areas in the United Kingdom and Germany.

The rapid development of my country's economy has also caused the area covered by acid rain to expand rapidly. By 1999, it had become the third largest acid rain area in the world after Europe and North America. my country still uses coal as the main fuel. A cause of serious air pollution.

The damage caused by air pollution is extremely widespread. In many cases, it does not appear in the form of poisonous fog, acid rain, etc., but all kinds of organisms are often affected by it, and the damage to forests and crops is particularly significant. Frequent breathing of polluted air is also a threat to human health, especially respiratory diseases, which increase. Living in a severely polluted atmospheric environment for a long time is like chronic poisoning.

The ozone in the atmosphere cannot make ends meet and its concentration is decreasing. Scientists first discovered in 1985 that: In September and October 1984, the concentration of ozone in the ozone layer over Antarctica dropped by 40% compared with the mid-1970s. It could no longer fully block excessive ultraviolet rays, creating this special circle that protects life. The emergence of "holes" threatens the survival of phytoplankton in the Antarctic ocean. According to a report by the World Meteorological Organization: In 1994, it was found that the ozone content in the stratosphere over the Arctic region also decreased, and in some months was 25-30% lower than in the 1960s. The hole in the ozone layer over Antarctica is still expanding. In September 1998, it set a historical record with an area of ??25 million km2. *

Why is there a "hole" in the ozone layer? Many scientists believe that it is the result of the use of Freon as a refrigerant and other uses. Freon is composed of carbon, chlorine, and fluorine. After the chlorine ions are released into the atmosphere, they can repeatedly destroy ozone molecules and remain in their original state. Therefore, even though the amount is very small, it can reduce ozone molecules to the point of forming a "hole." Chinese scientists recently proposed that the role of Freon alone is not enough. The flow of particles from the solar wind is concentrated toward the geomagnetic poles under the action of the geomagnetic field and destroys the ozone molecules there. This is the main reason. (Yang Xuexiang, 1999) In any case, artificially sending chlorine ions into the atmosphere is ultimately a harmful behavior.

In the atmosphere, matter is loosely distributed and moves rapidly. The slightest external interference may break the original balance. Therefore, the impact of human activities on the atmospheric environment cannot be underestimated.

There are about 100 kinds of pollutants in the atmosphere that have caused harm or been noticed by people. Among them, the ones that have a wide range of impacts and pose a greater threat to the human environment mainly include hydrocarbons, carbon monoxide, nitrogen oxides, Sulfur oxides, hydrogen sulfide, fluoride, photochemical oxidants and particulate matter, etc.

(2) The hydrosphere is seriously polluted

The biggest problem in the hydrosphere is the shortage of fresh water resources and uneven geographical distribution, which has become an obstacle to the sustainable development of some countries and regions (see Chapter Chapter 12), and the pollution of the hydrosphere has threatened the survival of mankind.

On the occasion of World Water Day in 1999, experts from the United Nations announced that in the world today, there are still 1.4 billion people drinking unsafe water, which causes more than 5 million deaths every year. In our country, after the rapid development of economic construction, most rivers have been polluted to varying degrees. In other countries, the more developed the industry, the more serious the water pollution becomes. The polluted air can be quickly diluted and dissipated through flow and diffusion; although polluted water can also flow, it often exists in relatively stable water bodies. It will have a long-lasting and profound impact on people and creatures that depend on water.

Of course, there are natural factors that cause water and water body pollution. However, the development of industry and the use of chemical fertilizers, pesticides and a large number of chemicals in daily life have made the pollution in the hydrosphere develop to the current level of harm.

Wastewater discharged from industrial production, domestic sewage and agricultural wastewater have often become the main sources of pollution today. Pollutants in water include metals, non-metallic substances and organic matter. There are many types of pollutants, many of which are harmful to the human body or even highly toxic. Although it can be purified through artificial treatment, most of them are now only slightly treated, or even discharged directly without treatment. into natural water bodies.

The Minamata disease that occurred in Minamata City and Nippon Prefecture in Japan in the 1950s and 1960s was caused by mercury in wastewater discharged from factories passing through the biological food chain (diatoms-flying mantis-grouper-eel ), the mercury content in the eel reaches 10-20 mg per liter (up to 50-60 mg per liter), which is 10,000 to 100,000 times higher than the mercury concentration in the original wastewater. After local residents preyed on eels, mercury accumulated in the human body, causing serious damage to the central nervous system. Water pollution has great harm to the human body and aquatic life. In particular, pollution from toxic and harmful substances can cause chronic poisoning, acute poisoning and even death. Water bodies contaminated by germs are the source of infectious diseases. Water pollution has great harm to the human body and aquatic life. In particular, pollution from toxic and harmful substances can cause chronic poisoning, acute poisoning and even death. Water bodies contaminated by germs are the source of infectious diseases.

The vast majority of rivers eventually flow into the ocean, and substances, whether harmful or harmless, are concentrated along the rivers into the ocean; oil tankers rupture or sink, and oil that can seriously pollute the ocean is carried away. Into the sea. In some places, people also dump garbage into the sea. The ocean is nature's cornucopia and self-purifying pool, but some people use it as a cesspool and trash can. The Mediterranean Sea, which is close to industrially developed areas, has long had no fisheries to speak of, and many species have become extinct here. my country's Bohai Sea has also seen this development trend due to the expansion of surrounding cities and the rise of industry. According to a 1998 report by the monitoring department, 56% of the Bohai Sea was polluted in 1995, which was one percent larger than ten years ago. times, and is still expanding. Water bodies such as rivers, lakes, and oceans originally have a self-purifying effect, so the water in nature is always so crystal clear. Now it is polluted and is still developing. This is entirely the result of careless human behavior. The hydrosphere is a system in which pollutants spread with the movement of water, so pesticides have also been found in the tissues of Antarctic penguins; and the red tide (red tide) that affects vast sea areas comes from urban sewage. These sewage are rich in phosphorus, nitrogen and other elements and organic matter required for biological nutrition. Red tide is a phenomenon in which some red or brown algae receive rich nutrients and grow rapidly and increase in number. Because they reproduce excessively, decay after death, and consume a large amount of oxygen, they affect other organisms, especially fish, which cannot survive here.