Its solubility in water is greater than 1g/L, and its chemical properties are quite stable. The natural degradation process of microcystins in water is very slow. When the content of microcystins in water is 5ug/L, only 10% is absorbed by particles in water after three days, and 7% is precipitated with sediment. Microcystins have high heat resistance and cannot be destroyed or removed by heating and boiling. Coagulation, sedimentation, filtration and chlorination of tap water can not remove it. A survey showed that low concentration of microcystins (128 ~ 1400 ng/L) were detected in the effluent of three water plants around the lake. The results showed that the microcystins in drinking water could not be completely removed by conventional disinfection treatment.
It is a hepatotoxin and a strong promoter of liver cancer.
Microcystins are also very harmful. The LD50 of MC-LR is about 50~ 100 ug/kg. When people take a bath, swim and do other water recreation, skin contact with water containing microcystins will cause sensitive parts (such as eyes) and skin allergies; A small amount of drinking can cause acute gastroenteritis; Long-term drinking may lead to liver cancer. Medical departments found that microcystins in drinking water have a great correlation with the incidence of primary liver cancer in the population.
There are many cyanobacterial toxins in fresh water, including hepatotoxin acting on the liver, neurotoxin acting on the nervous system and endotoxin located in the outer layer of cyanobacterial cell wall. Generally, endotoxin and lipopolysaccharide are considered to be the same substance. Hepatotoxin includes microcystin (MC), coccidioscin and columnar sperm protein. Microcystin is cyclic heptapeptide, and Arthrococcal toxin is cyclic pentapeptide. Neurotoxins mainly include ANABAENA toxin -A, ANABAENA toxin -a(s)[anatoxin-a(s)], saxitoxin, neosaxitoxin and gonyautoxin, among which the last three are collectively referred to as. Anabaena toxin -a is secondary amine base, Anabaena toxin -a(s) is guanidine methylphosphate, and paralytic shellfish poison is carbamate.