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Human Impacts > Chemical and Waste Pollution > Sediment Pollution > Disease Pollution

Disease Organisms
In the last 100 years, people in the United States have been affected by outbreaks of polio, typhoid fever, infectious hepatitis, cholera, and dysentery. These diseases have several things in common. All of these diseases are caused by are microscopic organisms, such as bacteria. All of these disease organisms live in wet environments. And, all of these outbreaks were caused by poor sanitation (waste disposal procedures). The good news is all of these disease outbreaks are preventable by sanitary water and waste practices.

What causes outbreaks?
Many disease organisms live in the intestines of humans and other animals. When an animal defecates, organisms in the animal's feces reach the outside environment. Most outbreaks are caused by disease organisms that get into the water as part of animal waste. Livestock produce large amounts of animal waste. Rainwater carries this waste from the land into our freshwater systems, such as rivers. Humans produce a lot of waste, too! When sanitation conditions are poor, human waste accidentally reaches the water supply. This can happen if sewage gets flushed directly into rivers or sewers without first going through a treatment plant.

Water treatment plants filter and add chlorine to the water. The treatment removes and kills harmful disease organisms. However, high levels of chlorine can be toxic to small animals and animal eggs, and harmful to humans. Therefore, the best solution to keeping to water free of disease organisms is to prevent water contamination in the first place. That is, follow sanitary water and waste practices strictly. To learn more about reducing your impact on the environment, see Protecting our watershed: What YOU can do to help.

Drinking or swimming in contaminated water exposes you to disease organisms in the water. Animals that live in the water, such as oysters and clams, may not become sick themselves from taking in contaminated water. However, if we eat these infected animals, we put ourselves at risk of becoming very, very sick.

Animals that are infected with disease organisms also pose an economic problem. It is not safe to harvest and sell contaminated oysters and clams. People that harvest oysters and clams may have trouble staying in business.

Remember, we all live downstream: in addition to local pollution, our water contains pollutants from people living upstream. And, of course, our pollution affects the water of people living downstream from us.

Get more info on E. coli