Can tap water be drunk directly?

Tap water has the following problems:

I. Heavy metal pollution

About 50% of the surface water sources in China are polluted, and hundreds of organic substances and heavy metal ions enter the water sources. There are problems such as excessive fluorine, arsenic, iron and manganese in underground water sources.

Second, the quality of water pipe network is poor.

According to the survey, the quality of urban water supply network in China is generally poor, with gray cast iron pipes accounting for 50.80%, ordinary cement pipes accounting for 13% and galvanized pipes accounting for 6%. The old pipe network leaks seriously and often bursts. Judging from the water quality, it is easy to produce secondary pollution.

Third, the second pollution incident

After long-distance transportation of tap water through pipelines, it is easy to cause secondary pollution due to aging and rust of water pipes. Chlorine can kill viruses and bacteria in tap water, but it can't remove sediments, rust, heavy metals, volatile substances, etc., and boiling doesn't help.

Fourth, the disinfection method of water quality is not perfect.

Because the disinfection method of tap water is not perfect enough, most tap water drinkers will use tap water. In the disinfection process, tap water is disinfected with bleaching powder (agent). Even if efforts are made to filter, there is still a small amount or trace of chlorine (bleaching powder). When water is heated at 100℃, chloroform will be produced, which is a carcinogen.

Extended data:

Direct drinking water filtration technology can be divided into nine levels:

The first stage: primary filtration of raw water to remove coarse impurities, sludge, colloid, suspended matter, etc.

Grade II, III and IV: composite filter is softened by KDF+ resin, and the KDF treatment medium is high-purity copper/zinc alloy. Through electrochemical redox (electron transfer) reaction, chlorine and heavy metals in water are effectively reduced or removed, and the growth and reproduction of microorganisms in water are inhibited. Sodium ions on the resin exchange with calcium and magnesium ions in water, activating water quality and enhancing activity.

The fifth stage: adsorption of odor, abnormal color, organic matter and some heavy metals in water.

Grade 6: contains edible and compound phosphate and various special formulas (different ASR formulas can be prepared according to the local water quality in the north), which can effectively remove heavy metal ions such as calcium and magnesium, soften the water quality, inhibit mineral scaling and block RO membrane in water, and effectively prevent excessive calcium and magnesium ions from forming stones in the human body and causing harm to the human body.

Grade 7: the pore size is 0. 1 micron, which removes organic impurities such as bacteria, viruses and heavy metals in water.

Grade 8: Improve the taste.

Grade 9: secondary biological sterilization to ensure the sanitary quality of effluent.

References:

Baidu Encyclopedia-Tap water (treated water for users)

People's Network-Is tap water safe?

Baidu encyclopedia-direct drinking water