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: 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. Every lawn, every farm, every golf course that uses phosphorus contributes a little bit. But add all those little bits together, and they account for 80% of the problem. Learn more about how excess nutrients in the water cause problems in the Gulf of Mexico's "Dead Zone". Changes in land use create changes in phosphorus
Since 1940, the amount of phosphorus in the St. Croix has risen dramatically. This coincides with two major changes in the way we use the land: