Waste products of industrial processes such as metal plating are notable contributors to this type of pollution. Once heavy metals are ingested in drinking water, they never leave the body. Increased concentrations can become toxic. Dust - Airborne particles around which water vapor may condense and fall as precipitation, or can merge with standing surface water making the water dirty and undrinkable. Trihalomethanes - A group of organic chemicals, suspected of being carcinogenic, which are formed in water when chlorine being used as a disinfectant reacts with natural organic matter such as humic acids from decayed vegetation.
Humic acids are present in all natural water used as sources of drinking water supplies.
Chloroform is one of the most common THMs formed in this type of reaction. Many provide the basic ingredient for acid rain, i.e. CO2 or SO2. Can cause difficulty in breathing and irritate eyes. On The Ground Animal Wastes - Wild or domestic, animal wastes can carry or initiate disease usually in the form of chlorine resistant cysts, such as cryptosporidium or giardia, or pathogenic bacteria, like coliform. Lyme's disease is passed in this way.