Examples of human destruction of the ecological environment

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

The coronavirus found by HKU in civet cats (commonly known as civet cats) is related to human SARS. Prior to this, Malaysian "Libai virus", new york's "West Nile virus" and even Hong Kong's "H5N 1 virus" all originated from animals, which are closely related to environmental damage, global warming, and the narrowing of the distance between humans and animals.

In addition to keeping our homes clean, we must also take a long-term view and protect the environment to prevent the emergence and spread of infectious diseases.

The impact of SARS on Hong Kong is rare in recent years. 1997 Although there was an outbreak of "avian influenza", the impact of this infectious disease gradually faded in the hearts of Hong Kong people due to the timely slaughter of chickens, the maintenance of the market clean day to this day and the vaccination of chickens. But looking around, the threat of infectious diseases has never stopped, but it does not happen in Hong Kong, and Hong Kong people have not paid attention to it.

Ecological variation virus spreads from person to person.

In the United States and other advanced countries, "West Nile virus" broke out from 1999. According to the website of the Centers for Disease Control and Prevention (CDC), the virus itself already exists in birds (in other words, birds are the hosts of West Nile virus). After mosquitoes bite birds with the virus, the virus will stay in their salivary glands and spread the virus by biting other birds and people.

Lao Yongle, president of the Hong Kong Medical Association, pointed out that the environment is closely related to human diseases. Another infectious disease related to animals is caused by Nipah virus. Since 1998, cases have appeared in Malaysia and Singapore.

It exists in bats in the forest, and then it is passed to pigs, and then it is passed from pigs to people. Tracing back to the source, everything originated from forest fires. Bats, originally living in Sabah, East Malaysia, escaped from forest fires and flew from East Malaysia to Malaysia Peninsula in West Malaysia, infecting pigs and people in pig farms. If it hadn't been for the fire in East Malaysia, it wouldn't have infected pigs.

He said that the fire was related to the very dry weather in that year, and the abnormal weather was affected by El Ni? o. It can be seen that infectious diseases are closely related to the environment and ecology. Moreover, the global temperature rise is conducive to mosquito reproduction, so it is also conducive to the spread of dengue fever; The rise of seawater temperature promotes the growth of plankton in water and depends on their cholera bacteria. Seafood eats plankton and eats these seafood instead. If people eat it without proper cooking, they will get cholera. This is why cholera broke out in Hong Kong a few years ago.

As for the "Ebola virus", Lao Yongle said that people cut down trees, destroyed the homes of apes who originally lived in forests, and forced them to contact with humans.

Killing animals, destroying habitats and spreading viruses

Mao, an academician of the Chinese Academy of Sciences and virologist, said in an interview with mainland media that there are a lot of viruses in many wild animals. No matter whether they are killed, domesticated or used for experimental purposes, viruses originally confined to animals have invaded human bodies. Ebola virus, HIV and yellow fever have little impact on their host apes, and the mortality rate is also very low. However, when human beings destroy habitats and expand their activities to virgin forests, the mortality rate of human beings is very high.

Such as LEPIDOPTERA virus, dengue fever, cholera, Ebola virus, etc. It shows that if people don't properly protect the natural environment and ecology, they will bring us unexpected disasters-infectious diseases.

SARS virus is related to civet cats. As for whether it is transmitted to people, it has not been fully confirmed as of press time. Lao Yongle pointed out that a large dam was built in Heyuan, one of the early SARS cases in Guangdong Province. Usually when the dam is built, the water level rises, people leave and animals leave. He believes that it is worth investigating whether it will force animals to leave their original habitats and increase the chances of contact with people. People will catch them and eat them before the coronavirus spreads to them.

Protect the environment and prevent the spread of infectious diseases.

Lao Yongle said that in order to prevent the occurrence of infectious diseases, attention should be paid to reducing the greenhouse effect and reducing the rise of seawater temperature. Small places should pay attention to their living environment, care for the environment and protect the forest.

Before SARS appeared, everyone didn't realize that infectious diseases still threatened modern areas such as Hong Kong.

Lao Yongle said that compared with the past, children's nutrition is better, and with the implementation of immunization programs, even if they suffer from measles, their lethality is much lower; Adequate and clean water sources have reduced the epidemic of cholera. Infectious diseases have been gradually ignored, and the focus of medical circles has shifted to chronic diseases such as heart disease and cancer. Ward planning is also based on "big rooms", but for infectious diseases, it will increase the risk of cross-infection.

"With SARS, there will be other infectious diseases. Old Yongle said that it is time to prepare for this.

(1) The atmospheric environment is deteriorating. The main manifestations are: the increase and intensification of climate disasters, global warming, melting glaciers, rising sea levels, and the threat of coastal lowlands being submerged by seawater; The change of atmospheric composition is not conducive to human beings, carbon dioxide increases, the concentration of ozone layer that relieves ultraviolet radiation decreases, the ozone layer above the earth's poles appears holes and is increasing, and many harmful components are also increasing. According to the report of American Ritchie National Laboratory 1997, since the industrial revolution, the concentration of carbon dioxide in the atmosphere has increased by 30%, methane has doubled, and nitrogen oxides have increased by 15%. Carbon dioxide, methane and nitrogen oxides are all gases that can produce greenhouse effect, and the increase of their concentrations leads to the increase of temperature.

These changes in the atmosphere are caused by nature itself. Volcanic eruptions and forest fires will release pollutants into the atmosphere. However, the use of fossil fuels such as coal and oil releases harmful gases and dust such as carbon dioxide, methane, nitrogen oxides and sulfur dioxide, which makes air pollution more serious. Coal burning produces the most pollutants. The resulting poisonous fog and acid rain are outstanding manifestations of air pollution. "Killing Smoke" first appeared in Belgium in 1930, and enveloped London four times from 1948 to 1962. The concentration of sulfur dioxide and dust in smoke greatly exceeded human tolerance, resulting in more than 6,000 deaths. Although this kind of record is rare, polluted air generally permeates the space of many industrial and mining areas and cities.

Ordinary rainwater often contains trace amounts of carbonic acid. Sulfur dioxide, nitrogen oxides and other components are added to the polluted atmosphere, which makes the rainwater more acidic. At present, people define rain with pH below 5.6 as acid rain. It looks like ordinary rain, but the acidic substances it contains enter the soil and water on the surface, and the organisms that depend on these water and soil are adversely affected, especially the destruction of forests. 1939 The pH value recorded as acid rain for the first time is 5.9 (pure water pH value is 7). In 1950s, the pH value of acid rain dropped to 3-5, and the lowest was 2. 1, which was almost even stronger than vinegar. It shows that with the development of industry, the degree of air pollution is becoming more and more serious. Because the atmosphere containing pollutants is mobile and can cross the ocean, the acidic components emitted by Japan can form acid rain in the United States, and it is not surprising that acid rain in Canada originated in the United States. Scientists have measured that two-thirds of the sulfur dioxide gas gathered over Sweden and Norway comes from industrial areas in Britain and Germany.

With the rapid development of China's economy, the area covered by acid rain has also expanded rapidly, with 1999 becoming the third largest acid rain area in the world, next to Europe and North America. China still uses coal as its main fuel, which is one of the reasons for serious air pollution.

The damage caused by air pollution is extremely extensive. Many times, it does not appear in the form of poisonous fog and acid rain, but all kinds of creatures are often affected by it, especially the damage to forests and crops. Frequent breathing of polluted air is also a threat to human health, especially respiratory diseases. Living in a polluted atmospheric environment for a long time is just like chronic poisoning.

Ozone in the atmosphere can't make ends meet, and its concentration decreases. Scientists first discovered in 1985 that in September and October of 1984, the ozone concentration in the ozone layer over Antarctica was 40% lower than that in the mid-1970s, which could not completely block too much ultraviolet rays, resulting in a "hole" in this special life protection circle, threatening the survival of Antarctic marine phytoplankton. According to the report of the World Meteorological Organization, it was found in 1994 that the ozone content in the stratosphere over the Arctic region also decreased, and in some months it decreased by 25-30% compared with that in the 1960s. However, the ozone hole over Antarctica is still expanding, with the largest area reaching 25 million Km2 in1September 1998. *

Why is there a hole in the ozone layer? Many scientists believe that it is the result of using freon as refrigerant. Freon consists of carbon, chlorine and fluorine. After chloride ions are released into the atmosphere, ozone molecules can be destroyed repeatedly and remain unchanged. Therefore, even if the amount is small, ozone molecules can be reduced to form "holes". Recently, scientists in China suggested that it is not enough to rely solely on the action of Freon. The particle flow of solar wind is concentrated to the geomagnetic pole under the action of geomagnetic field, where ozone molecules are destroyed, which is the main reason. (Yang Xuexiang, 1999) In any case, artificially discharging chloride ions into the atmosphere is a harmful behavior.

In the atmosphere, substances are loosely distributed and move at a high speed, and small external disturbances may also upset the original balance, so the impact of human activities on the atmospheric environment cannot be underestimated.

There are about 100 kinds of pollutants that have been harmful or noticed in the atmosphere, among which hydrocarbons, carbon monoxide, nitrogen oxides, sulfur oxides, hydrogen sulfide, fluoride, photochemical oxidants and particulate matter are the main threats to the human environment.

(2) The hydrosphere is seriously polluted

The biggest problem of 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 12), and the pollution of hydrosphere has threatened the survival of mankind. 199 On the occasion of World Water Day, UN experts announced that1400 million people still drink unsafe water in the world today, and more than 5 million people die of diseases every year. In China, after the great 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. The polluted atmosphere can be diluted rapidly after flowing and diffusing; Although polluted water can also flow, it often exists in relatively stable water bodies. It has had a long-term and far-reaching impact on people and creatures living on water.

There are natural factors that cause water and water pollution. However, with the development of industry and the use of fertilizers, pesticides and a large number of chemicals in life, the pollution of hydrosphere has developed to the present harmful level.

Wastewater discharged from industrial production, domestic sewage and agricultural backwater often become the main pollution sources today. There are many kinds of pollutants in water, including metals, nonmetallic substances and organic substances, many of which are harmful to human body and even highly toxic. Although it can be purified by manual treatment, most of it is only slightly treated, or even directly discharged into natural water without treatment.

In 1950s and 1960s, Minamata disease occurred in both Minamata City and Niigata Prefecture, Japan. The reason is that the mercury in the wastewater discharged by the factory is gradually enriched through the biological food chain (diatom-flying squid-grouper-eel), so that the mercury content in eel reaches 65,438+00-20 mg per liter (up to 50-20mg). After local residents preyed on eels, mercury accumulated in the human body, causing serious damage to the central nervous system. Water pollution is very harmful to human body and aquatic organisms, especially the pollution of toxic and harmful substances will cause chronic poisoning, acute poisoning and even death. Water polluted by germs is the source of infectious diseases. Water pollution is very harmful to human body and aquatic organisms, especially the pollution of toxic and harmful substances will cause chronic poisoning, acute poisoning and even death. Water polluted by germs is the source of infectious diseases.

Most rivers eventually flow into the ocean, and harmful and harmless substances are concentrated in the ocean with the rivers; The rupture or sinking of an oil tanker is bringing oil that may seriously pollute the sea into the sea. In some places, people also dump garbage into the sea. The ocean is a cornucopia and self-purification pool of nature, but some people regard it as a sewage pool and a garbage can. Near the developed industrial areas, there are no fishing grounds in the Mediterranean, and many species are extinct here. Due to the expansion of surrounding cities and the rise of industry, this development trend also appears in Bohai Sea in China. 1998 The report of the monitoring department shows that 56% of the Bohai sea area in 1995 is polluted, which is twice as large as that of ten years ago and is still expanding. Rivers, lakes and oceans all have self-purification functions, so the water in nature has always been crystal clear, and now it is polluted and still developing, which is completely the result of human carelessness. The hydrosphere is a system in which pollutants diffuse with the movement of water, so pesticides are also found in the tissues of Antarctic penguins. The red tide (red tide) that affects the vast sea area comes from urban sewage. These sewage are rich in phosphorus, nitrogen and other elements and organic matter needed for biological nutrition. Red tide is a phenomenon that some red or maroon algae get rich nutrition, grow rapidly and increase in number. Because of their excessive reproduction and decay after death, they consume a lot of oxygen, which affects other organisms, especially fish.