Nitrates

Nitrates are chemical compounds that are made from the elements nitrogen and oxygen. All plants and animals need nitrogen in order to make proteins, to grow, and to reproduce.
When plants and animals die, proteins are broken down by bacteria forming ammonia. Ammonia is broken down by other bacteria to form nitrite. Ammonia and nitrite are both poisonous to animals. Nitrite is then consumed by a third type of bacteria which forms nitrates. However nitrates can be used by plants in order to grow. This recycling of nitrogen through the environment is called the nitrogen cycle.

Testing for Nitrates

Nitrates can be tested for in a variety of ways. Most tests involve a color metric change. Some kits measure this change through electronic means, others use a simple color wheel comparator.

Results

The results of the amount of total nitrates found in the North Channel of the Chicago River are listed below:

Site	Amount of Nitrates
1	0 (mg/L)
2	1 (mg/L)
3	1 (mg/L)

Influences

Nitrate is a major ingredient in most fertilizers. When it rains, varying amounts of nitrates wash from farmlands and lawns into nearby streams. Nitrates can also enter streams from animal wastes and sewage.
Nitrates can be harmful to humans. It is broken down in our intestines becoming nitrite. Nitrite affects the ability of red blood cells to carry oxygen. If infants consume water high in nitrite/nitrates, they may suffer from a serious condition called methemoglobinemia or blue baby disease. Wells contaminated by sewage or agricultural run off are a major concern in some areas. Nitrites can also cause serious illnesses in fish.