NITRATE AND PESTICIDES IN MINNESOTA PRIVATE WELLS: PART 1

The MDA determines current nitrate-nitrogen concentrations in private wells, on a township scale, through the Township Testing Program. The MDA has identified townships throughout the state that are vulnerable to groundwater contamination and have significant row crop production. More than 70,000 private well owners will be offered nitrate testing in over 300 townships by 2019.

Each selected township is offered testing in two steps, the “initial” sampling and the “follow-up” sampling. In the initial sampling, all township homeowners using private wells are sent a nitrate test kit. If nitrate is detected in their initial sample, the homeowner is offered a follow-up nitrate test, pesticide test and well site visit. As of January 2017, 167 vulnerable townships from 19 counties participated in the TTP from 2013 to 2016. Overall, 9.5% (1,912) of the 20,042 wells exceeded the HRL for Nitrate-N.

Homeowners who had a Nitrate-N detection in their initial sample are offered the opportunity to have their well sampled again for nitrate-N and approximately 125 pesticides as part of the Private Well Pesticide Sampling Project (PWPS). The MDA has sampled approximately 3,765 wells in nineteen counties for nitrate-N and pesticides from 2014-2017. Pesticides and/or pesticide degradates were detected in 76% of the wells sampled in 2016. The MDA anticipates that approximately 5,800 wells in 52 counties will be sampled by the time the PWPS Project is complete in 2020.

This presentation will be given in two parts. The first 20 minutes Kimberly Kaiser will focus on the background, initial homeowner nitrate testing and the follow-up nitrate testing and the second part of the presentation (20 minutes) will be given by Jeff Paddock focusing on the pesticide results.