Orthophosphates and polyphosphates can be contributed by detergents, as discussed below. Detergents Orthophosphates and certain polyphosphates are major constituents of many commercial cleaning preparations. The extensive use of detergents led to major eutrophication problems, and in the 1960s efforts were made by governments, detergent manufacturers, and consumers to reduce the use of phosphates in detergents. As a result, phosphorus concentrations in many streams and lakes decreased. This was due to limits on the phosphate content of detergent, and also additional treatment used in waste water treatment plants to remove phosphorus.
Many states have a ban on phosphates in detergents.
Fertilizers Fertilizers generally contain phosphorus in the form of orthophosphate. However, if too much fertilizer is applied, the phosphates are carried into surface waters with storm runoff and also with melting snow. Soil erosion of fertilized fields and lawns can also carry a considerable amount of particulate phosphate to streams. Animal Waste Phosphorus is essential in metabolism, so is present in animal waste. Therefore, phosphate runoff can be an issue in waters near cattle feedlots, hog farms, dairies, and barnyards.