Do soaps have thesame effects on eutrophication?

Answer 1

Soaps often contain compounds called phosphates. Phosphate has the chemical formula PO4, meaning one phosphorous atom and 4 oxygen atoms. Phosphates are always combined with another element, such as sodium or calcium. so typically you see ingredients like NaPO4, and so on, instead of just phosphate. In addition, in soaps, the ingredients are often named with "organic" descriptions, from organic chemistry, that are hard to decipher. However, you can usually see the word "phosphate" in there somewhere.

All living organisms need phosphorous, and they can get it from dissolved phosphates. Typically plants and microbes absorb phosphate and it enters a food chain. It is vital. The problem is that when you put too much (put too much Tide in your washing machine, wash your dishes with a quart of dish soap, to exagerrate mildly) soap in an environment, the phosphates stimulate the producers at the bottom of the food chain to overproduce, because they have much more phosphorous than is naturally and normally available.

Algae is one such "producer". Too much phosphate stimulates tons and tons of algae to grow in a water ecosystem that is polluted. The algae literally blocks to absorption of oxygen at the surface, because the atmosphere can't really make contact with the water- the dense algal "bloom" is in the way. In addition, the algae blocks sunlight to oxygen producing organisms lower down in the water. Also, as the algae dies, oxygen using micro organisms that eat dead algae also experience a huge boom in population, using up the oxygen that does exist. All of this seems slightly counter intuitive, because algae itself is an oxygen producer. You can see, however, why massive amounts of it cause de-oxygenation of water.

In turn, of course, animals are killed- they enter oxygen free water and die of lack of oxygen, and you get giant fish kills. Other organisms that need oxygen die as well. If this happens very often, an ecosystem can be completely disrupted, everything gets out of balance, extinctions occur, and we have once again damaged things beyond fixing.