The latter can be
heavily chlorinated or have too high a concentration of minerals.
Avoid swimming in
heavily chlorinated pools, and be sure to shower before and after swimming, using soap and clean water.
That would include everything from the sulfates in soaps to the chlorine and
heavily chlorinated water.
Water that is
heavily chlorinated or has gone through a water softener can kill off the bread yeast and prevent the dough from rising.
If it is not contained, the entire pool must be evacuated and closed for 24 hours so they can
heavily chlorinate it!