Evan
I think one of the reasons for the green algae growth under these lighting conditions is the refraction and absorbance of light in a liquid (water) as well as the refraction in the cell membrane. Particulate matter with in the water may also effect the transition of light with in the body of water.


As for chlorine’s health effects, I feel that inhalation is the greatest cause for concern (Pool doc has already coverd that one). The skin, being a selective membrane, can tolerate high levels of many materials depending on the transport material it is in. Our skin is selective in non isotonic solutions with exceptions that should not occur in a normal pool environment. I would have a greater concern if your pool is salted to an isotonic state.
Solutions that could cause posing through the skin usually cause cell damage and prevent more absorbance through the body in general. The toxins that do manage to cross the epidermal layer are usually long term toxins causing general damage to the DNA.
Before I get nailed I am speaking of the chemistry found in the normal residential pool setting.
I would much rather deal with the few free radicals I may encounter in the pool with the right chlorine balance than deal with the microbe nastiness you will encounter with out it.
Steve