1. What is chlorine

Through the study of high school chemistry, we know that chlorine is a yellow-green gas with a strong irritation. Chlorine has a wide range of uses, and liquid chlorine is often used for sterilization in water plants. When chlorine is inhaled, it can quickly react with the moisture on the surface of the respiratory tract mucosa and alveoli to generate hydrochloric acid, which can cause burning and irritation to local tissues. Severely cause edema, congestion, and necrosis. The peripheral receptors in the mucous membrane of the respiratory tract are stimulated, which can cause a local smooth muscle spasm, aggravate ventilatory disorders and cause hypoxia and damage the myocardium. Chlorine can damage the central nervous system and cause dysfunction, mainly manifested in the parasympathetic nerve due to increased excitability and low blood pressure, sinus bradycardia, and arrhythmia. Exposure to low concentrations of chlorine is mainly manifested as mucosal irritation: such as pungent eye membranes, tearing, sore throat, dry cough, chest tightness, and nausea. Inhaling a higher concentration of chlorine can immediately cause persistent coughing, chest tightness and shortness of breath, and obvious headaches, dizziness, irritability, general weakness, sleepiness, and other symptoms, as well as nausea, vomiting, abdominal pain, etc. Acute gastrointestinal reaction. Some can cause chemical pneumonia, the longer the inhalation of high concentrations of chlorine, the development of pulmonary edema, causing coma and shock.

2. The bath water should be free of residual chlorine

Chlorine is a yellow-green gas with a strong irritant. Chlorine has a wide range of effects, and liquid chlorine is often used for sterilization in water plants. When chlorine is inhaled into the human body, it can quickly react with the moisture on the surface of the respiratory tract mucosa and alveoli to generate hydrochloric acid, which can cause burning and irritation to local tissues. In severe cases, it can cause edema, congestion, and necrosis. Chlorine can damage the central nervous system and cause dysfunction, mainly manifested in the parasympathetic nerves due to increased excitability and low blood pressure, sinus bradycardia, and arrhythmia.

Tap water contains a small amount of residual chlorine. In a closed bathroom, the residual chlorine and nitrite in the water vapor can increase in concentration as the temperature of the bathwater rises, and it is quickly absorbed by the body through the expansion of sweat pores. These chlorine-containing harmful substances are often several times or even dozens of times higher than the usual intake of drinking water. They will not only cause dry skin, itching, and hair loss but even more serious loss of elasticity of capillaries.

If you use a water purifier to remove the residual chlorine in the bathwater, you can avoid the harm of the residual chlorine to the human body.

Expert: Not adding chlorine will cause an infectious disease outbreak

“Hahaha…” Liu Wenjun, secretary-general of the Water Industry Branch of the Chinese Civil Engineering Society and professor at Tsinghua University burst into laughter after hearing the reporter’s retelling that “the residual chlorine in tap water can cause cancer”. He told reporters that this seemingly “scientific” rumor is nonsense at all, and many deductions are alarmist.

“Chlorine is indeed a toxic chemical, but whether chlorine is harmful to the human body depends on the time and dose of intake.” Liu Wenjun said that chlorine is a high-quality and economical bactericide, and it only forms a toxic gas at high concentrations. Chlorine dissolved in water will become hypochlorite, which greatly reduces its harmfulness. “If chlorine is poisonous, wouldn’t it be ‘poison’ if we eat salt (chemical name sodium chloride) every day?”

Liu Wenjun has studied water safety standards in more than 100 countries, and 95% of them use chlorine as a disinfectant. “Chlorine plays an important role in the safety of tap water, effectively curbing the spread of pathogenic bacteria in water bodies and preventing the concentrated outbreak of malaria, dysentery, and typhoid fever.”

Liu Wenjun said frankly that it is indeed possible in theory that the residual chlorine in the water reacts with the precursor of the disinfection by-product after heating to produce chloroform. “We discovered this problem in 1972 and started to control it. At present, the domestic tap water organic matter content control is extremely strict.” He said, assuming that the organic matter and residual chlorine in the water reach the current national standard upper limit, it is per person to drink two liters of water per day. , Calculated after drinking for 70 years, the cancer rate caused by drinking tap water is less than one in a million. The inhalation of chloroform caused by bathing is even negligible.

“Tap water is a non-selectable public product. We must first be responsible for the safety of citizens.” Liu Wenjun said that the risk of carcinogenicity caused by residual chlorine in tap water is very low, but if liquid chlorine is used for sterilization, the risk of a large-scale epidemic will be much higher.