Mineral oil chemicals are a mixture of various hydrocarbons. Petroleum can exist in wastewater in dissolved, emulsified and dispersed state. When the oil content exceeds 1.1 ~ 1.4 mg/L after entering the water environment, it can form an oil film on the water surface, which will affect the reoxygenation process of the water body, cause hypoxia in the water body, and endanger the life of aquatic organisms and aerobic degradation of organic pollutants.

Oil pollution in water is the most common and serious pollution in marine pollution. Petroleum is a complex natural organic mixture with certain toxicity. It can also make fish taste like oil at a very small concentration. A large amount of oil forms an oil film on the sea surface, which will affect the oxygen supplement in water and the photosynthesis of plants. Oil pollution will have a variety of complex effects on the natural environment. Oil in industrial wastewater can also pollute surface water.

Extended information:

1. Main sources

Oily sewage is formed when oil enters the water environment through different channels. Oily sewage is a kind of sewage with large quantity, wide area and serious harm. Every year, 5 million to 11 million tons of oil enters the water body through various channels all over the world. According to its source, it can be divided into: natural source (about 8%) and human activity source (about 92%). ?

the natural sources are mainly seabed, continental shelf leakage, oil-bearing sedimentary rock defects, etc. The main sources of human activities are oil tanker accidents, leakage and blowout accidents in offshore oil exploitation, oily sewage discharge from port and ship operations, oily wastewater from petroleum industry, catering industry, food processing industry and car washing industry.

second, the impact of oil pollutants on fisheries

the damage caused by oil pollution to the water environment to fisheries is various. First of all, oil pollution can destroy fishing grounds, contaminate fishing nets, aquaculture equipment and catches, and water pollution can directly cause fish death and directly reduce the catch.

Secondly, the output value is lost. Oil pollution can make fish and shrimp produce special smells and tastes, and these smells and tastes can't be eliminated no matter what processing methods are adopted, thus reducing the edible value of aquatic products and seriously affecting their economic utilization value. When the oil content in seawater is 1.11 mg/L, fish, shrimp and shellfish can smell within 24 hours.

when people eat aquatic products contaminated by carcinogens derived from petroleum hydrocarbons, especially polycyclic aromatic hydrocarbons, these carcinogens can endanger human health and safety through the transmission of food chain. In addition, oil pollution in water bodies will also cause considerable social and economic losses, such as affecting tourism and entertainment.

Baidu Encyclopedia-Oil Pollution in Water Body