Essay On Crayfish

In fact, the gills are the most sensitive and important part of fish. Once the structures of gills are changed by chemicals from polluted water, it is difficult for fish to be alive for a long time.
Moreover, unclean water can cause animals’ genes to change. There are a lot of colors of crayfish such as red, blue and pink. People think those colorful crayfish are beautiful and special. Some scientists discovered that some crayfish contains many metals in their body, so their genes get changes and their phenotype is changed from original color, red, to blue or other colors. Furthermore, those metals come from the place where crayfish lives, and polluted water has many metals. Hence, polluted water causes crayfish to change colors of hard shells. Most of time people buy blue crayfish and only put it at home because people know that colorful crayfish can only be looked at instead of eating because nobody wants to die.
In addition, the health
Sewage can poison shellfish, but shellfish can be still alive after that. However, people do not have resistance and immunity as good as shellfish. When people eat poisoned shellfish, they can get illness called paralytic shellfish poisoning. When people boil the shellfish, paralytic shellfish poisoning goes into water because it is soluble in water. However, this poison can resist heat and acid, so it cannot be marred by other cooking method. When people eat the shellfish, the poison is still there and eaten by people.
In brief, the health of vegetation, animals, and human beings can be impacted a lot by water pollution. Water pollution problem is a significant world problem. Governments not only need to pay a lot of attention on the pollution problem, but also need to focus on how to reduce the effects of water pollution efficiently. In fact, everyone needs to be concerned about this problem and protect the environment as best as he or she