大学化学课件9水体污染英文精编整理

Section 4 Water Body Pollution 1. Water body pollution and self-purification Definition The discharge of pollutants by human activity into the rivers, lakes, oceans or ground water etc, make water and water of sediment physical, chemical or biological community composition change, so as to reduce water use value, this phenomenon is called water body pollution Physical self-purification Chemical self-purification Biological self-purification Water purification is the phenomenon that the concentration of pollutants in water body is decreased gradually due to physical, chemical, biological action and returns to pre-contamination state finally. 2. Pollutants in water body (1) Pathogenic(病原性) pollutant For instance, Virus, germina, parasite Schistosomiasis 血吸虫病 Super bacteria Malaria In 1848 and 1854, ten thousands people died of cholera because of water pollution in England. In 1892, 750 people died of cholera in Germen. Cholera Smallpox Dysentery Hepatitis Characteristic of pathogenic pollutant： Big quantity wide distributing long life fast reproduction drug-fast good life-force (2) Oxygen consumed pollutant Carbohydrate, protein, grease, xylogen Sulfureted hydrogen, ammonia (3) Plant nutriment Nitrogen and phosphorus is from sewage, fertilizer, waste, trash. Definition of eutrophication (4) Venomous pollution 1) Heavy metal: mercury, cadmium, chromium 2) Inorganic ion: NO2-, F-, CN- Definition Sorts Toxic pollutant is a kind of materials, which enter organisms, accumulate, affect the biochemical and physiological function of the body fluids and tissues, then cause temporary or lasting pathological state, even life-threatening. Pb, V, Co, Ba 3) Organic pesticide, PCB 5) Common organic substances 4) Carcinogen：Polycyclic Aromatic Hydrocarbons, PAH；Heterocyclic compounds；Aromatic amines Common organic compound (5) Crude oil pollutant (6) Radioactive pollutant (7) Acid, base and salt inorganic pollutant (8) Heat pollution 40K、238U、286Ra、210Po、14C、3H 90Sr、137Cs 3. Water pollution effects on human health (1)