Ask A Scientist© Chemistry Archive

 >>    name         Natasha Ford
 >>    status       student
 >>    age          16

 >>    Question -   Are there any kinds of soap that instead of helping clean
 >> up waters
 >>pollute them even more?Please answer before saturday december 16th 1999

Considering that I just got the question on the 17th of December, I don't
suppose the answer will reach you in time.  Of course,mthe 16th was a
Thursday, so I'm not sure when you want this.

There really is no soap that cleans up waters.  Basically, in order for
something to become clean, something else must become dirty.  When you
clean something, such as your hands, with soap and water, your hands become
clean and the water becomes dirty.  The water is contaminated with both the
dirt that was on your hands and the soap.

Some soaps are more of a problem in water than others.  Laundry detergents
used to contain phosphates as "builders," that is, compounds to scavenge
metal ions and acids that would interfere with the detergent's sudsing and
cleaning action.  Problem was that the phosphates turned out to be
excellent fertilizers for waterborne algae, which choked waterways, died,
settled to the bottom, and, decaying, removed the dissolved oxygen from the
water.  Without oxygen, most of the animal life in the lakes and streams
died.  Nowadays, soaps do not use phosphates.  Also, some soaps persist in
the environment longer than others.  Most soaps in consumer products today
break down quickly in the environment, so that they don't make a sudsy
froth in waterways.


                Richard Barrans Jr., Ph.D.
                Chemical Separations Group
                Chemistry Division CHM/200
                Argonne National Laboratory
                9700 South Cass Avenue
                Argonne, IL 60439
                richb@anl.gov

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