Aquatic Pesticides

These perform a certain task on a area for a number of reasons, including controlling aquatic plants. With open systems (rivers) they can be carried into unintended areas and mess up the ecosystem. Just because they are permitted does not mean they are harmless.

http://connect.in.com/dead-fish-in-maryland/photos-1-1-1-3086dad001b6dc826669893e984743a3.html