According to the estimation of the United Nations Health Organization, at present, 1/4 of the population is sick because of water pollution. Every day, 25,000 people die from drinking polluted water, most of them are children with weak resistance, and 4.6 million children die from diarrhea every year because of drinking polluted water.
The harm of water pollution to human health is mainly manifested in the following four aspects:
One is to cause acute and chronic poisoning. After water is polluted by toxic chemicals, it may cause poisoning through drinking water or food chain. This acute and chronic poisoning is the main aspect of water pollution endangering human health. 1972 "Minamata disease" occurred in Minamata Bay and other places in Japan, 283 people were poisoned and 60 people died. This is caused by the pollution of water by industrial wastewater containing mercury. Mercury will gradually accumulate in humans and animals. Mercury poisoning is mainly manifested as brain injury, and the symptoms are stomatitis, gingivitis, nervousness, headache, trembling, diarrhea, vomiting and anemia. It turned out that the industrial wastewater containing methylmercury polluted the water around Minamata Bay, poisoning the fish in Minamata Bay, and methylmercury gradually enriched in the fish, making people miserable after eating the poisoned fish. 1963 "Osteodynia" occurred in Kawaguchi, a prodigy in Fushan County, Japan, which caused many victims, including 8 1 death. This is caused by cadmium-containing industrial wastewater polluting the water body. After cadmium enters the human body through human diet, it causes cumulative poisoning. One is to cause kidney damage and reduce the reabsorption capacity of renal tubules. Excessive calcium is lost from urine for a long time and can't be replenished, so calcium is absorbed from bones, which leads to osteoporosis and osteomalacia, and the patient's bone pain is unbearable, hence the name "bone pain". It turned out that industrial wastewater containing cadmium polluted the water body of Shentongchuan, and farmers on both sides of the strait irrigated farmland with river water, which made rice contain cadmium, and residents were poisoned after eating polluted river water and rice. In addition, lead is also a pollutant harmful to human health. Even if a small amount of lead is ingested, it will seriously damage the kidney, brain and circulatory system. Lead is more harmful to the fetus and children under 7 years old. Because of the poor barrier function in children, lead will cause serious and irreversible damage to the developing brain and nervous system, which can cause children's mental retardation, behavioral deviation, slow growth and poor hematopoietic function. Even mild lead poisoning can lead to children's inattention, decreased memory, decreased understanding and ADHD. A survey by American scientists found that about 250,000 school-age children in the United States drink lead in water every year, which is enough to affect children's intellectual and physical development.
The second is to induce cancer. Cancer is the most common incurable disease in human society today. Speaking of cancer, it is inevitable that there will be a feeling of "talking about the tiger's color change". However, comparing drinking water with cancer has added some doubts and worries to the shock. But modern science has strongly proved that there is a causal relationship between drinking water and cancer incidence. Some carcinogenic chemicals, such as arsenic, chromium, nickel, beryllium, aniline and other aromatic hydrocarbons, chlorinated hydrocarbons, chlorinated aromatic hydrocarbons, etc., can accumulate in suspended solids, sediments and aquatic organisms after polluting water bodies. If people drink water containing such substances for a long time, or eat organisms containing such substances, it is easy to induce cancer. American experts found that the cancer mortality rate of tap water residents in Ohio is higher than that of groundwater, because surface water pollution is heavier than groundwater. According to the statistics of the United Nations Health Organization, one thousandth of people in the world suffer from cancer every year, and more than three million people die of cancer every year, accounting for about 1/4 of the total number of deaths in the world. The cancer mortality rate in developed industrial countries such as the United States, Britain, France and Japan is second only to cardiovascular diseases. More and more studies show that most cancers are caused by chemical carcinogens in the environment, which are widely found in surface water, groundwater and treated drinking water. Since 1974, more than 2 100 chemical pollutants have been found in drinking water in the United States, of which 97 have been identified as carcinogens and suspected carcinogens, and 133 are mutagenic, tumorigenic or toxic pollutants. Whether or not carcinogens are found in the remaining 90% pollutants has not been determined. Where do these carcinogens come from? Obviously, carcinogens in surface water and groundwater mainly come from industrial wastewater, fertilizers and pesticides. Many elements are essential trace elements for human body, but if the content of drinking water is too high, it will do harm to human body.