Title: Where does the phosphorus come from? | Science Buzz
Headings: Where does the phosphorus come from?
Where does the phosphorus come from?
Phosphorus doesn't stay put
Phosphorus comes from many places
Changes in land use create changes in phosphorus

Content: We put it on grass to make it grow. We put it on golf courses to keep them green. It occurs naturally in sewage. But the phosphorus doesn't stay where we put it. It clings to the soil. And when the soil washes away, it carries phosphorus with it. The St. Croix River, especially Lake St. Croix, collects water from the entire basin, concentrating the phosphorus in one place. Phosphorus comes from many places
You might think that the biggest sources of phosphorus are the obvious ones—sewage treatment plants, chemical factories, and the like. But in fact, identifiable sources such as these contribute less than 20% of the phosphorus in the river. The rest comes from a wide array of diffuse sources.