**3. Toxic effect of microcystins**

Many researches have confirmed that the compounds produced by various varieties of cyanobacteria are harmful to many animals and humans, as they have been discovered to cause the death of many creatures in many parts of the world, including cattle, horses, dogs, birds, fish, and crocodiles. These toxins have a direct impact on society Zooplankton, particularly those that prefer cyanobacteria species as a major food source, such as the genus Daphnia, where it was discovered that low concentrations of these toxins reduce the ability of these organisms to reproduce new generations, as well as their members' growth rates. Toxic levels above a certain threshold cause death [13]. The use of water contaminated with microcystins in the dialysis process in a hospital's hemodialysis unit, which resulted in damage Acute hepatitis, confirms the seriousness of these toxins, as the worst accident recorded so far occurred in 1996, with the victim (60 patients) due to the use of water contaminated with microcystins in the dialysis process. Due to the usage of recycled water for drinking, Western culture is one of the societies most exposed to these poisons, as proven by two occurrences in Australia. Due to pollution of drinking water with these chemicals, the first victim (139 children) and a number of adults became infected, resulting in severe liver, hematuria, renal failure, and death. The high concentration of toxin in the drinking water was caused by the chemical treatment of water containing blooming algae (*Microcystis aeruginosa*) with copper sulfate CuSO4, which is commonly employed to kill algae cells. High body temperature, skin rash, enteritis, general weakness, lack of appetite, pallor of mucous membranes, vomiting, diarrhea, liver poisoning, and death within hours or days, depending on the amount of dose given and the weight of the animal, are common signs of microcystin poisoning. The most common cause of death is an abrupt bleeding within the liver. Microcystins, according to the majority of researchers in this subject, have a stimulating influence on the growth of malignant tumors when consumed low concentrations and for long periods [14].
