Marine pollutant according to their origin, nature and toxicity, can be divided into the following categories: ① petroleum and its products (see marine oil pollution). ② metal and acid, alkali. Including chromium, manganese, iron, copper, zinc, silver, cadmium, antimony, mercury, lead, metals, phosphorus, arsenic and other non-metals, and acid and alkali. They are directly detrimental to the survival of marine life and affect its value in use. ③ pesticides. Mainly by runoff into the ocean. There are hazards to marine life. ④ radioactive material. Mainly from the nuclear explosion, the nuclear industry or nuclear ship sewage. ⑤ organic waste and sewage. By the runoff into the ocean. Very serious red tide can be formed. ⑥ thermal pollution and solid waste. Including industrial cooling water and engineering residual soil, waste and dredged mud. Into the sea after the former can improve local sea water temperature, the content of dissolved oxygen is reduced, the impact of biological metabolism, and even the biological communities change; the latter can destroy habitat seaside environment and marine life.