As we all know, people cannot go a day without "salt". Table salt is one of the essential substances of the human body. The human body contains 0.15% sodium and 0.15% chlorine. The amount of salt consumed by adults per day is generally controlled at about 6g, which maintains the function of muscles and nerves, while maintaining the normal excitement of muscles and the permeability of cells.
News media often appear to eat industrial salt and cause poisoning reports, so what exactly is industrial salt? What are the differences in the nature of table salt and industrial salt? How to identify the two and how to prevent industrial salt poisoning has become a concern for many people.
What is industrial salt
In actual production and life, the meaning of industrial salt is very broad, sometimes refers to pure sodium nitrite, sometimes refers to sodium chloride containing sodium nitrite, and in some cases, refers to industrial sodium chloride. It can be seen that industrial salts do not necessarily contain sodium nitrite. However, people usually say that industrial salt refers to industrial sodium chloride, which often contains toxic and harmful impurities such as sodium nitrite. Industrial salt poisoning incidents in the news media are mostly poisoning caused by excessive consumption of sodium nitrite.
The difference between edible salt and industrial salt
Structurally
Table salt is the purer sodium chloride, the chemical formula of sodium chloride is NaCl, the formula 58.44, composed of chloride ions and sodium ions. In addition to containing sodium chloride, there is also sodium nitrite exceeding the standard, the chemical formula is NaNO2, the formula is 69.00, composed of nitrite ions and sodium ions.
In nature
The salt is relatively stable, and the aqueous solution is neutral. Sodium nitrite is relatively stable under dry conditions, but it can slowly absorb oxygen and oxidize into sodium nitrate, and the aqueous solution is alkaline.
Appearance
Both are white, and in special cases table salt may also appear yellow or light blue, and sodium nitrite may also be slightly yellowish. Both are crystal-shaped, and there are certain differences in geometry under the microscope, but they cannot be distinguished by the naked eye.
solubility
Sodium nitrite and table salt are very soluble in water, easy to deliquescence, odorless.
flavor
Sodium nitrite is slightly salty, salt is salty, and it is difficult to distinguish between taste and taste when eaten. From the above comparison, it can be seen that sodium nitrite is similar to table salt in appearance and taste, which is easy to cause accidental ingestion poisoning.
Important uses for table salt and industrial salt
Sodium nitrite is mainly used in dyes, medicine, printing and dyeing, bleaching and other aspects, widely used as a rust inhibitor; due to its color-enhancing, bacteriostatic and anti-corrosion effects, it is mostly used in the food industry as a color additive for cooked meat food. According to the provisions of China's "Sanitary Standards for the Use of Food Additives" (GB2760-2014), the maximum amount of use in meat is 0.15g/kg, and the residual amount of sodium nitrite in meat shall not exceed 0.05g/kg in canned food; meat products shall not exceed 0.03g/kg.
The standard for the safe intake of sodium nitrite issued by the World Food Hygiene Scientific Committee in 1992 is (0 to 0.1) mg/kg weight; if converted to nitrite, its standard is (0~4.2)mg/60 kg weight, and it will not cause harm to the human body when used and consumed according to this standard. The amount of poisoning of sodium nitrite in the human body is 0.3g ~ 0.5g, and the lethal amount is 2g per kilogram of body weight, which can form nitrosamines in the human body with secondary amines in protein foods, which is a strong carcinogen.
Table salt is used industrially for dyes, ceramics, metallurgy, leather, soap and alkali making. In daily life, it is mainly used for seasoning and salty agent. At the same time, it is also an indispensable substance for life and is closely related to human health. Table salt is produced according to GB5461 standard, and adults generally consume 5g to 8g per day. Table salt is non-toxic, but excessive intake can easily lead to an increase in the incidence of cardiovascular disease.
Poisoning mechanisms and symptoms of accidental consumption of industrial salt
Sodium nitrite is toxic, the mechanism of human poisoning is that nitrite has a certain oxidation, after entering the human body, it can make the low ferritoglobin in the blood oxidize into methemoglobin, lose the function of oxygen transport, resulting in tissue hypoxia, so that the human body appears bruised and poisoned.
After excessive ingestion of nitrite poisoning, the onset is rapid, and the general incubation period is 1h to 3h, resulting in paralysis of the vascular motor center, respiratory center and surrounding blood vessels, and the formation of methemoglobin. Acute intoxication manifests as general weakness, headache, dizziness, nausea, vomiting, diarrhea, chest urgency, dyspnea, cyanosis of the skin and mucous membranes on examination, severe decrease in blood pressure, coma, and death.
Rescue methods
Mild poisoning is generally not treated, and the more severe ones should be immediately sent to the hospital for rescue. The main therapeutic measures are: emetic, gastric lavage and vomiting. The use of the antidotes Methylenelan (Melan) and vitamins has a certain effect on eliminating methemoglobinemia. Large doses of vitamin C and glucose are given.
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Source: Secondary School Chemistry, No. 11, 2016