Polyacrylamide and its hydrolysates are low-toxic. Most products do not irritate the skin. However, some hydrolysates may have residual alkalinity, which can be irritating when repeated and prolonged contact. Avoid direct contact with skin during loading, unloading and use.
Many polyacrylamide products have been approved by the US Environmental Protection Agency and the Food and Drug Administration for use in drinking water treatment, sugar juice clarification of fruits, vegetable washing, etc. However, the maximum dose applied is limited. The residual amount of acrylamide in the polymer should be less than 0.05%. Polyacrylamide itself is basically non-toxic, because after it enters the human body, most of it is excreted in the short term and is rarely absorbed by the digestive tract. Most commodities do not irritate the skin, only some hydrolysates may have residual alkali, which can be irritating when repeated and prolonged contact. The toxicity of polyacrylamide comes from residual acrylamide monomers and toxic heavy metals entrained in the production process.
Acrylamide is a neurotoxic agent and has a damaging effect on the nervous system. After poisoning, it exhibits symptoms such as muscle weakness and movement disorders. Since the starting material for polyacrylamide is cyanide-acrylonitrile (AN), which is highly toxic, it is quite natural for people to pay attention to the toxicity of polyacrylamide. The discharge standards of AN in foreign industrial wastewater are set at 0.1 x10-6 (British and Su), 0.2x10-° (US). In fact, as far as polyacrylamide is concerned, the AN content in polyacrylamide is generally 3 x
Below 10, if the 200x10-6 polyacrylamide treatment wastewater is the maximum addition, the maximum content of AN in the treated water is only 0.006 x10-*, so the impact of polyacrylamide on the water quality can be ignored. The toxicity of acrylamide was studied as early as 1954 by the American Cyanamide Company, and then the American Dow Chemical Company conducted a systematic animal test, and this type of research abroad has continued to this day. Studies have shown that acrylamide has moderate toxicity. In terms of acute poisoning, 10% acrylamide aqueous solution is easily absorbed and causes irritation after contact with the skin. 40% high concentration solution can cause painful damage to the conjunctiva and cornea in contact with the eye. A single dose of acrylamide injected into the cat's peritoneal cavity at a dose of 100 mg/kg body weight can cause severe neurotoxicity; at 200 mg/kg, the monkey can die. Therefore, foreign researchers suggest that the industrial exposure of acrylamide should be controlled so that the daily absorption of workers does not exceed 0.05 mg/kg body weight, and the total absorption of residents is limited to 5 mg/kg body weight.
There have been many studies abroad on the toxicity of nonionic and anionic polyacrylamides. Studies have shown that no matter the animals are fed, no abnormalities are found in human contact. The situation of some cationic polyacrylamides is much more complicated. This is because the amine groups and other groups in cationic polyacrylamide are often more toxic than anionic and nonionic types by tens to hundreds of times. Polyacrylamide. Their chronic toxicity is under further study. The toxicity of various acrylamide copolymers should be considered separately. The dried cationic polymer is toxic and its oral (for rats) and transdermal (for rabbits) LD50s are greater than 5.0 g/kg body weight and 20 g/kg body weight, respectively. The oral (for rats) and transdermal (for rabbits) LDg values of nonionic, anionic and cationic emulsion polymers are all greater than 10 g/kg body weight. Preliminary stimulus studies on exemptions have shown that dry nonionic and cationic polymers do not irritate the skin and are extremely irritating to the eyes. The dry anionic polyacrylamide is not irritating to the eyes or skin of laboratory animals. The non-ionic emulsion polymer is severely irritating to rabbit eyes, while the anionic and cationic emulsion polymers are extremely irritating to rabbit eyes.
The content of residual acrylamide in polyacrylamide industrial products is regulated by the health departments of various countries, and generally ranges from 0.5% to 0.05%. When applied to water-like purification treatment, the acrylamide content is below 0.2%; when used for direct drinking water treatment, it must be below 0.05%. The acrylamide standard published by the International Health and Health Organization in 1985 states that when the residual amount of acrylamide in polyacrylamide is controlled below 0.05% and the amount is controlled, the content of acrylamide in the treated water will be lower than
0. 25μg/L, in line with drinking water standards of most countries. The content of acrylamide in the discharged water should be between 1 ~ 50μg/L. Therefore, the main European and American countries generally stipulate that the residual acrylamide content in polyacrylamide for drinking water treatment and food industry should be below 0.05%, and control the amount of polyacrylamide .
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