Cecil here is an article where potassium is mentioned in the pollution of water.
http://www.epa.gov/glnpo/atlas/glat-ch4.htmlFrom the article below.
Increased nutrients in the lakes stimulate the growth of green plants, including algae. The amount of plant growth increases rapidly in the same way that applying lawn fertilizers (nitrogen, phosphorus and potassium) results in rapid, green growth. In the aquatic system the increased plant life eventually dies, settles to the bottom and decomposes. During decomposition, the organisms that break down the plants use up oxygen dissolved in the water near the bottom. With more growth there is more material to be decomposed, and more consumption of oxygen. Under normal conditions, when nutrient loadings are low, dissolved oxygen levels are maintained by the diffusion of oxygen into water, mixing by currents and wave action, and by the oxygen production of photosynthesizing plants.
Also when I was on vacation in the Wisconsin Dells in the late 50's the soap suds from phosphates in washing detergents was so thick on the river that it floated in large chunks two to three feet high and six feet long like Islands. Phosphates were later band in washing detergents.
Since I walked and kayaked a lot of streams I was asked by a water conservation group in IN. to take a water sampling kit and sample water ways to determine what chemicals were in the waters, the concentration and where they were at. I said I would but the fastest way to find the chemicals and concentrations coming into the streams was to sample the farm drainage tile dumping into the streams. I was told that would cause too many problems and so I told them I wasn't interested. So there you have it. Industry and cheap food will always top clean water. That's why I built my pond so I could have a clean natural water area to enjoy.
