Main hazards of persistent organic pollutants

POPs are mostly lipophilic and hydrophobic complex organic halides with stable chemical properties and good fat solubility, which are easy to damage the human liver and affect the body such as immune function, hormone metabolism, reproductive inheritance and so on. Its harm is mainly manifested in "three causes" (carcinogenic, teratogenic and mutagenic) and many other aspects that have great influence on health. At present, persistent organic pollutants have become a global environmental problem, mainly because they will cause irreversible and serious harm to wildlife and human health, including:

1) is harmful to the immune system. POPs can inhibit the normal response of immune system, affect the activity of macrophages and reduce the virus resistance of the body. A study on Inuit people found that the ratio of healthy T cells to infected T cells in breast-fed and milk powder-fed infants was related to breast-feeding time and pesticide POPs content in breast milk. According to the survey of persistent organic pollutants in Beijing, 90% of more than 300 pregnant women's milk collected in Beijing were found to have persistent organic pollutants such as polychlorinated biphenyls or organophosphorus pesticides, of which 10% was at a dangerous level.

2) Harm to endocrine system. Many persistent organic pollutants have been proved to be potential endocrine disruptors, and they have strong binding ability with estrogen receptors, which will affect the activity of receptors and then change the gene composition. It was found that the levels of polychlorinated biphenyls (PCBs) and DDE (metabolites of DDT) in breast tissue of women with malignant breast cancer were higher than those of women with benign breast tumors.

3) Harm to reproduction and development. When organisms are exposed to persistent organic pollutants, reproductive disorders, congenital malformations and organism death will occur. A study of 200 children (3/4 of whose mothers ate fish contaminated with POPs during pregnancy) found that these children were born with light weight and small size, and their cognitive ability was worse than that of ordinary children at 7 months, and their IQ was even lower at 1 1 year-old, and their reading, writing, calculation and understanding abilities were poor. For example, the press disclosed that in the 1960s, during the Vietnam War to resist US aggression and save the nation, the US military dropped 2,4,5 trichlorophenoxyacetic acid, which is called defoliant, in the forest area of South Vietnam. Forty years later, people living in this land paid a heavy price for it, and a large number of terrible deformed children such as stillbirth, abortion, cerebral palsy, no feet, no legs, big head, small head and cleft palate appeared. /kloc-The IQ of 0/8-year-old adults is only equivalent to that of a child, and this serious environmental pollution problem may even last for generations.

4) Carcinogenesis. Other toxic POPs can also cause pathological changes in other organs and tissues (such as liver and kidney function damage and thyroid function damage). ), leading to epidermal keratinization, pigmentation, hyperhidrosis, elastic tissue lesions and other skin symptoms. Some persistent organic pollutants may also cause symptoms of mental illness, such as anxiety, fatigue, irritability and depression. Cardiovascular diseases, such as chronic ischemic heart disease, hypertension and chronic rheumatic heart disease. It can be seen that the problem of environmental hormone pollution endangering human health cannot but be worrying.