Pesticides In The Environment MEDIUM EPA Aquatic Pesticide Label Guidance

When treating an entire weed-choked farm pond with an aquatic herbicide during mid-summer, what commonly causes catastrophic fish mortality?

Multiple Choice Options

A Massive bacterial decomposition of dead aquatic vegetation, consuming all dissolved oxygen in the water column. ✓ OFFICIAL VERIFIED CORRECT ANSWER
B The weeds explode mechanically and rupture fish scales.
C Water temperature drops to 32°F instantly.
D Fish swim onto the shoreline to forage.
✓ LEGAL EXPLANATION & STATUTORY RATIONALE
EPA Aquatic Pesticide Label Guidance
Official Manual Chapter: Chapter 7: Environment & Aquatic

Decomposing plant mass depletes dissolved oxygen (BOD surge), causing fish suffocation. Labels mandate treating only 1/3 to 1/2 of the water body at a time.

Official EPA Core Study Domain Pesticides In The Environment
Practice All Domain Questions →