High chemical oxygen demand means that water contains a lot of reducing substances, mainly organic pollutants. The higher the chemical oxygen demand, the more serious the organic pollution in the river water. The sources of these organic pollution may be pesticides, chemical plants, organic fertilizers, etc. If not treated, many organic pollutants can be adsorbed and deposited on the bottom of the river, which will cause lasting poisoning to aquatic organisms in the next few years. After a large number of aquatic life died, the ecosystem in the river was destroyed.
If people feed on organisms in the water, they will absorb a large amount of toxins in these organisms and accumulate in the body. These poisons often have carcinogenic, teratogenic, and mutagenic effects and are extremely dangerous to humans. In addition, if contaminated river water is used for irrigation, plants and crops will also be affected, and they will easily grow poorly, and people cannot eat these crops.
However, a high chemical oxygen demand does not necessarily mean the aforementioned hazards. Specific judgments need to be analyzed in detail, such as analyzing the types of organic matter, and how they affect water quality and ecology. Is it harmful to humans? If detailed analysis is not possible, the chemical oxygen demand can also be measured on the water samples at intervals of a few days. If the value drops a lot compared with the previous value, it means that the reducing substances contained in the water are mainly easily degradable organic substances, which are relatively harmful to the human body and biology. light.