Discharging industrial. untreated domestic and agricultural wastes as well as untrea sewage into water sources causes water pollution. Excess fertilizers. pesticides and herbicides used in farms are washed into ponds by rain. This may pose a streams or threat to our health and aquatic organisms. Untreated sewage will cause the spread of waterborne diseases. Untreated discharge from factories can be poisonous and may cause death when consumed. oil spill is a well-known ocean pollution. Many aquatic organisms and seabirds die and ecosystems are destroyed due to this