The sources of radionuclides in the environment are natural and man-made. In the human environment, there are natural radioactive substances such as uranium, thorium and potassium 40, plus cosmic radiation lines that expose a person to about 100 millirems of radioactive radiation per year, called natural background radiation. Man-made mainly nuclear weapons testing and the resulting fallout, only between 1961 - 1962 a year amounted to 337 megatons, resulting in global environmental pollution, others such as nuclear fuel mining and processing, leakage of nuclear reactors, nuclear fuel reprocessing and other exacerbated the radioactive contamination of the environment.
Radioactive substances on human health hazards is very large, a one-time exposure to a large number of radiation can cause death, such as the atomic bomb attack during World War II, Hiroshima, Nagasaki into a piece of rubble. Receiving a large dose of radioactive radiation after a certain incubation period can appear various tissue tumors or leukemia. Radiation destroys the body's non-specific immune mechanism, reduces the body's ability to defend itself, and is prone to infections and shortens life. In addition, radioactive radiation has a teratogenic, mutagenic effect, in pregnancy by irradiation is very easy to make the embryo death or the formation of teratology.
Radioactive contamination of the population health hazards is very large, so it is necessary to strengthen a variety of radioactive "three wastes" governance and emissions management, the development of radiation protection standards, to strengthen the monitoring of radioactive substances, in order to reduce the radioactive contamination of the environment. In addition, personal protection should be strengthened, as far as possible away from radioactive sources, if necessary, wear protective clothing.
Radioactive pollution refers to environmental pollution caused by radioactive substances. Radioactive substances can enter the human body through the air, drinking water and the complex food chain and other ways, or external irradiation to jeopardize human health, causing radiation sickness .
Specifically:
In nature and artificially produced elements, there are some that can automatically decay and emit rays that are invisible to the naked eye. These elements are collectively known as radioactive elements or radioactive substances. In the natural state, the rays from the universe and the Earth's environment itself radioactive elements generally do not bring harm to living creatures. since the 1950s, human activities have made artificial sources of radiation and artificial radioactive substances greatly increased, the intensity of the rays in the environment and consequently enhanced, endangering the survival of living creatures, resulting in radioactive contamination. Radioactive contamination is difficult to eliminate, and the intensity of rays can only decay over time.
Radioactive pollution mainly comes from nuclear weapons tests, radioactive waste discharges from the nuclear industry, leaks from various nuclear accidents, and a variety of devices with radiation sources, such as X-ray sources and television picture tubes.
In 1945, the United States dropped two atomic bombs on Hiroshima and Nagasaki in Japan, killing hundreds of thousands of people, and a large number of survivors also suffered from radiation sickness. Atmospheric nuclear testing, so that a large number of radioactive fallout contaminated the atmosphere, the ground and the sea. Nuclear power plants produce large quantities of radioactive waste during the production, use and recycling of fuel. There are also nuclear submarine accidents, crashes of aircraft carrying nuclear bombs, and crashes of nuclear-powered satellites into the atmosphere, which likewise cause nuclear contamination.
Radioactive substances in the environment can enter the human body by a variety of ways, and the rays they emit can destroy the macromolecular structure of the organism, or even directly damage the cellular and tissue structure, causing damage to the human body. High-intensity rays can burn the skin, cause leukemia and various types of cancer, destroy the human reproductive function, and in severe cases can be fatal in a short period of time. A small amount of cumulative irradiation will cause chronic radiation sickness, so that the hematopoietic organs, the cardiovascular system, the endocrine system and the nervous system and other damage, the onset of the process often extends for decades.
Conventional three-waste pollution
is a serious public health hazard. Three wastes refer to wastewater, waste gas, waste residue. Pollution refers to water, air, soil and other ecological factors in the process of human production and life by the production of chemical substances, radioactive substances, pathogens, noise and waste heat and other pollution to a certain extent, jeopardizing human health, affecting the normal activities of living organisms phenomenon. After the three wastes are discharged into the environment without treatment, the mercury metal in the three wastes can generate methylmercury, which increases its toxicity and enters the fish through the food chain, and when people eat fish, the mercury accumulates and is poisoned in the human body. The people of Minamata town in southern Kyushu, Japan, were victimized by more than 10,000 people, with one hundred and eighty people suffering from illnesses and more than 50 people dying, and the disease caused by the accumulation of mercury in the future was called "Minamata disease". In addition, the cadmium in the three wastes, after accumulation in the human body, will destroy the calcium metabolism in the bone, kidney damage, bone pain unbearable, and finally bone softening and atrophy, natural fracture, the general human body from the cadmium to the onset of the disease need to be after ten to thirty years, so we should advocate the production of industrial and agricultural production of non-waste production or less waste production, and the promotion of recycling process. For example, the recycling of caustic soda in the paper industry, equivalent to one-third of China's annual production of caustic soda. Recovery of coking gas up to three billion cubic meters, equivalent to ten times the amount of gas in Beijing.