1) The water quality before 1970s, people can even continue to drink it, but now let's see what's different about water quality: According to statistics, since 1970s, industrial wastewater and domestic sewage have been discharged up to 62 billion tons every year, of which 80% have been discharged into natural water without any treatment.
2) According to the World Health Organization (WHO) survey, 80% of diseases in the world are caused by drinking polluted water; Up to now, 1.2 billion people in the world have suffered from various diseases due to drinking polluted water; The number of infectious diseases such as cholera and dysentery caused by water pollution exceeded 5 million; Up to now, 50% of cancers in the world are caused by drinking polluted water.
3) According to the statistics of the Chinese Academy of Preventive Medicine, the water consumption of E. coli in 900 million people in China exceeds the standard; 380 million people are drinking water with excessive oxygen consumption; 110 million people drink high hardness water; 50 million people drink high nitrate water; 9.48 million people drink water with excessive fluoride. Only 23% of the residents in 35 key cities in China basically meet the hygiene standards. At present, most residents in our country use tap water as drinking water, but at present, tap water can't be drunk, for two reasons: 1. The problem of bactericides. The purification of tap water in our country is mainly through chlorination. When drinking water is chlorinated and disinfected, chlorine reacts with organic substances in water, which will produce a series of chlorinated by-products, which are volatile and nonvolatile. Most of these by-products are carcinogenic and mutagenic. Experts concluded that drinking chlorinated tap water for a long time is the key to the increase of cancer in modern people. Chlorination disinfection of drinking water has caused many controversies in the world. In 1974, in New Orleans, USA, the chlorine in tap water exceeded the standard, which caused local cancer lesions and mortality rates much higher than those in other areas. 2 It is the secondary pollution of the city. The tap water itself has only undergone coarse filtration. After long pipelines, various construction and maintenance, water leakage, water seepage and other conditions, we can check it when we come to our home. As far as Beijing is concerned, the water quality in each district is different, and the tap water value in the same city has a gap. That's why we can't drink tap water raw.
4) 2221 kinds of organic matter have been detected in water all over the world. According to Shanghai Drinking Water and Health, there are 700 kinds of organic substances in Huangpu River and 317 kinds of organic substances in Songhua River in Jilin Province, most of which are related to human tumors. Before the 19th century, water pollution was mainly biological pollution, that is, pathogenic microbial pollution, which caused numerous infectious diseases and plagues, such as cholera, typhoid fever, hepatitis A, poliomyelitis and so on. It is also common for people to suffer from parasitic diseases caused by eating contaminated water or food. Water pollution in the 20th century is mainly reflected in chemical pollution, which is divided into inorganic pollution and organic pollution. Inorganic pollution such as: heavy metals such as lead, mercury, chromium, cadmium and cyanide, fluoride, arsenide, nitrite, etc.; Organic substances such as phenols, pesticides, insecticides, detergents, etc. Cancer, as we all know, has become the most panic-stricken disease in recent years. At present, the incidence rate is second only to cardiovascular disease, and it is the second most serious disease in the world. More than 3 million people die of cancer every year. More than 2,100 kinds of chemical pollutants have been found in American drinking water, among which 97 have been confirmed as carcinogens and suspected carcinogens, and 133 kinds of mutagenic, tumorigenic and toxic pollutants. These carcinogenic factors mainly come from industrial wastewater and chemical fertilizers and pesticides.
5) Water pollution caused by various reasons, there are many kinds of endemic diseases in China, such as endemic fluorosis, lithiasis and cancer villages.