One study found that even slightly acidic conditions may deform or kill tadpoles. Acidic conditions have been linked to the decline of the natterjack toad in England. Next End Pollution Pollution wears many faces. There are direct sources like dumping and factory pipes, and indirect sources like pesticide run-off from farms and weed killer or motor oil from storm drains. If pollutants don't kill the frogs right away, they may affect their insides and cause problems down the road.
Frogs absorb water through their skin.
If that water is polluted, those chemicals are absorbed as well. Frog eggs are the same way. Pollutants from copper mines in Arizona have wiped out the nearby population of Tarahumara frogs. The ozone layer has been broken down by man-made junk like CFCs. These scientists from Oregon State University have shown that when the eggs of several Cascade amphibians were exposed to UV-B radiation they died more often than ones that were not exposed.