Herbicide contaminants

Asked April 29, 2018, 5:45 PM EDT

I have a domestic well, 137 ft deep, buried in heavy blackberry bushes. What R the risk factors for using Crossbow on the blackberries around my drinking water well?

Multnomah County Oregon

2 Responses

Hello and thanks for your question.

One of the biggest risk factors has to do with well construction. If the well casing is intact, the risk of contamination is much lower. That means the herbicide would have to travel over 100 feet through soils to reach the water table, rather than entering the well water through a faulty casing. Some symptoms of a cracked well casing include:

  • sudden appearance of dirt or cloudy water
  • reduction in the well water flow rate
  • appearance of bacteria, which would lead to unusual taste/smell of well water
If you're concerned about your well casing, you might consider having it inspected. They use a camera for this type of thing, and there are "sleeves" that can be used to repair cracks.

Next, let's talk about Crossbow. I looked up the label, and it says:
"This chemical has properties and characteristics associated with chemicals detected in groundwater. The use of this chemical in areas where soils are permeable, particularly where the water table is shallow, may result in groundwater contamination."

Sandy soils are much more "permeable" than clay/loam soils. If you don't know the depth of your groundwater, consider contacting your local Extension office. One of their specialists should be able to give you an educated guess, based on his/her knowledge of the county. Here's a link where you can find your local Extension office: http://npic.orst.edu/mlrDetail.html?state=OR#countyExtension

Next, it makes a big difference if you read and follow the directions carefully. Don't over-apply the product, and wait for 2-3 weeks to determine the effectiveness. Some folks will re-apply the product after a week, only to find out that the second application was unnecessary.

This publication has more information about how to control blackberry bushes near water (riparian areas).

Please don't hesitate to ask follow-up questions. Take care,

Thank U, Kaci B. Very very much. I appreciate how much research U put into this. My well AND blackberries are on a pretty steep cliff so mechanical / motorized means just won't "cut it", to coin a phrase. Was going to spray, then burn off the debris after they wilt. don't know about root sustems but anything will help. Again, thank you so much for all your help.

Michael O'Keeffe