It's really nothing new, humans almost wiped out the American Bull Frog by using certain chemicals in farming. Growing up I can remember catching giant Bull Frogs that weighed between 2-4 lbs. I flat out love frog legs and would enjoy mom cooking up a dozen or so for me when I'd come home with them. But 10 years later....I couldn't find any large ones at all and the small ones were few and far between. Even the Leopard Frogs were damaged from the chemicals.
Thankfully it seems that the American Bull Frog is starting to come back again. It just shows how we can screw up the environment and wildlife with our chemicals and almost wipe out a species such as the Bull Frog.
A concern I have now is, what have we done and are doing to our water source(rivers, lakes, oceans) that will show up down the road? We already have notices on how many fish we can consume from bodies of water!