Pond Boss Forums INTRO Questions & Observations Herbicide in the pond

Finally a calm wind day on the southern plains today so I sprayed some pre-emergent and herbicide on the place before lunch. Sprayed on the back side of the dam but there is very little chance of any drift as the bottom of the dam is about 15' lower than the rim. Also, was using a tank with booms that are maybe a foot off the ground.

However, my collie managed to get under the spray and then went and waded in my pond before I could stop it. Several hours later I observed a very ill adult BG gasping for air near the surface right where the collie was wading. The pond is about an acre and average depth of about 8'. I have BG, HSB, LMB, and RES. I've never seen any fish do that before so I'm doubting its a coincidence. I observed the pond and didn't see another sick fish at dusk.

How big of a mess have I made?

I am by no means an expert, but I doubt enough herbicide rode in on the dog to do any harm. I also doubt itnhas to do with the gasping fish, but I could be wrong.

You could start here and look up your herbicide (or read the label that came with it).

MSDS Labels

See what toxicity it has for fish. Some are not very toxic at all, others more so.

I can't imagine a Collie could get enough herbicide on it to affect a BOW unless it it the size of a stock tank. Any reasonable sized pond the minimal amount even a drenched Collie could carry of already diluted to application rate spray chemical would be a tiny amount of contamination, in my opinion.

If it were toxic enough to fish in such small concentration I would probably be worried more about the Collie than the fish, but I am no chemist.

The label indicates toxicity to fish. I agree with the expressed sentiments. Just thought it an odd coincidence. But coincidences DO occur.

The heck with the fish, how's the dog? What's the toxicity to mammals?

May I ask, what was the chemical(s)?

Pendimethalin 37.4%.

http://www.epa.gov/espp/litstatus/effects/pendimeth/analysis.pdf

"Pendimethalin exhibits high toxicity to fish"