Most environmental pollutants are produced by human production and living activities.
Some substances are originally useful substances in production, and even essential nutrients for humans and living things. They are discharged in large quantities due to underutilization, which not only causes waste of resources, but also may become environmental pollutants.There are many types of pollutants and their properties are different. The nature of pollutants can be summarized as follows.
(1) Naturalness. Humans who have lived in the natural environment for a long time have strong adaptability to natural materials. Some people analyzed the distribution of more than 60 common elements in the human body, and found that the majority of them in the human blood are very similar to their percentage in the earth’s crust. However, humans are much less tolerant of synthetic chemicals. So distinguishing the natural or artificial properties of pollutants helps to estimate how harmful they are to humans.
(2) Toxicity. The toxicity of cyanide, arsenic and its compounds, mercury, antimony, lead, organic phosphorus and organochlorine in pollutants is very strong (3) Temporal and spatial distribution. After the pollutants enter the environment, they are diluted and diffused with the flow of water and air, which may cause a greater range of pollution from the point source to the surface source, and the concentration and intensity distribution of the pollutants over time in different spatial locations. The change is different, which is determined by the diffusibility of pollutants and environmental factors. Contaminants with good water solubility or high volatility can often be transported to a greater distance by diffusion. (4) Activity and persistence. Indicates how stable the pollutants are in the environment.
Highly active pollutants are prone to chemical reactions in the environment or during processing to produce pollutants that are more toxic than the original, which constitute secondary pollution and seriously endanger humans and organisms (5) Biodegradability. Some pollutants can be absorbed, utilized and decomposed by organisms, and finally produce harmless stable substances. Most organisms have the potential to be biodegraded (6) Bioaccumulation.
Some pollutants can accumulate and accumulate in humans or organisms, especially in the long-term accumulation in internal organs. From quantitative to qualitative changes, lesions occur, endangering human, animal and plant health (7) Additiveness to the action of living organisms. In the environment, the possibility of only one pollutant is small, and often multiple pollutants exist at the same time. It is necessary to consider the combined effect of multiple pollutants on the organism