Polychlorinated biphenyls can be absorbed by human body through animal skin, respiratory tract and digestive tract. The digestive tract has a high absorption rate. When the low chlorine dose is within 100 mg/kg body weight and the high chlorine dose is within 5 mg/kg body weight, 90% of oral intake can be absorbed quickly. Since the 1960s, PCB poisoning in poultry and human beings caused by environmental pollution basically occurred after oral invasion and digestive tract absorption. Polychlorinated biphenyls (PCBs) are widely distributed in whole body tissues after being absorbed by humans or other animals, and the content of PCBs is the most in fat. The acute toxicity test of polychlorinated biphenyls (PCBs) to mammals showed that the lethal dose per kilogram of body weight of rabbits was 8 ~ 1 1g, that of mice was 2g, and that of rats was 4g ~1.3g.. Severe poisoning animals can see diarrhea, blood and tears, ataxia, progressive dehydration, central nervous system inhibition and other diseases, and even death. Long-term low-dose exposure of animals to drugs can produce chronic toxic effects, and the poisoning symptoms are periorbital edema, depilation, acne-like skin damage and so on. The pathological changes of poisoned animals are hepatomegaly, small fat droplets and smooth endoplasmic reticulum hyperplasia in the central lobule. Biochemical determination showed that PCBs could induce liver microsomal enzymes obviously, especially for PCBs with high chlorine content. Animal reproduction experiments show that PCBs can affect the fertility of rats. The carcinogenic effect of polychlorinated biphenyls on rodents was studied.
The toxicity of polychlorinated biphenyls (PCBs) varies greatly with animal species, sex, feeding methods, chemical structure of PCBs and impurities contained in them. Humans are probably the most sensitive species. Ingesting a small amount of PCBs will lead to "oil disease" that once happened in Japan.
In acute and subacute poisoning experiments, the LD50 (lethal dose 50) of KC-400 is about 2g per kg body weight, and the mice died 1 ~ 4 days after administration. The LD50 of intraperitoneal injection of 2,4,3 ′, 4 ′-tetrachlorobiphenyl was 2. 15g/kg body weight. The cause of death was acute liver failure. The LD50 of polychlorinated biphenyls (PCBs) in rats is about 4g (AR- 122 1) to1.3g (ar-1262) per kilogram of body weight. When AR- 1254 was injected intravenously once, the LD50 of female rats was 358 mg/kg. The main causes of death are progressive dehydration and central nervous system depression.
The most typical example of PCB's harm to people is 1968 Japanese rice bran oil poisoning incident. The victim was poisoned by eating rice bran oil contaminated with polychlorinated biphenyls (2000 ~ 3000 mg of polychlorinated biphenyls per kilogram). The patient has the following symptoms: acne-like rash, eyelid edema and increased eye secretions, pigmentation of skin and mucosa, jaundice, numbness of limbs, gastrointestinal dysfunction and so on. As of 1978, 28 counties in Japan (including Tokyo, Kyoto and Osaka) have officially confirmed that 1684 patients are PCB poisoning patients; More than 30 people died of this disease before 1977.