In general, the Minnesota Department of Agriculture (MDA) cleanup programs use a site specific, risk based approach for investigation and remediation decisions. Many sites are cleaned up to a point that they no longer pose a risk to human health and the environment. When a site is not cleaned up to these standards, the project is considered closed with contingencies. Some control is required to prevent exposure to the remaining contamination on the site. All sites with contingencies are mapped with a GIS polygon to identify the area closed on a contingent basis. The locations of contingently closed sites and the type of restriction and/or contingency may be found through a search in the MDA’s What’s In My Neighborhood-Agricultural Interactive Mapping tool. The information available also includes a link to a PDF file for each site describing the type of restrictions and/or contingencies associated with the site.
Contingent Closures
In some situations contamination is left in place because the presence of a structure or building does not allow removal or treatment of the contaminated soil. This closure typically requires that the site owner notify the MDA if the structure is to be removed so that the soil beneath it can be investigated and if necessary remediated. The MDA’s follow-up on these sites involves an annual site visit or letter to the responsible party and/or landowner to ensure that conditions have not changed and to ensure that the current landowner and/or facility manager is aware of the contingencies.
Many of the contingent closures are on abandoned agricultural chemical facilities which were closed without investigation. Based on an evaluation, it was determined that the possible risks associated with these sites were too low to warrant investigation. These sites are referenced in the MDA database as not investigated and no Incident Response Unit (IRU) follow-up is conducted.
Institutional Controls
When sites are closed that still have the potential for adverse effects to human health or the environment, institutional controls are used to limit use of the land or the resource. For instance, a restrictive covenant could be placed on the property deed, or a zoning restriction could be established, that would prevent residential use of a property if that use is not consistent with the level of cleanup. Likewise, a local ordinance could be adopted that does not allow the installation of shallow wells if groundwater is contaminated. Sites with institutional controls require action on the part of the responsible party, the landowner, a city, county and/or the MDA to maintain the institutional control and to implement corrective actions if needed in the future.
Deed Affidavits and Restrictive Covenants: In these cases, an affidavit or restrictive covenant is attached to the deed to ensure that property owners are aware of the residual contamination and the land use requirements and restrictions. The MDA staff inspect these sites regularly to ensure that site conditions have not changed and to ensure that the current landowner and/or facility manager is aware of the restrictions.
Local Ordinances: Local ordinances may be established to restrict land or resource use within the area of concern. The MDA staff follow-up on these sites involves contacting the unit of government responsible for the ordinance to make sure that the ordinance is still in place and being enforced.
Special Well Construction Areas: Special Well Construction Areas (SWCA) are established by the Minnesota Department of Health (MDH) for areas where groundwater contamination exists at levels of concern. The MDH SWCA remains in effect until removed by the MDH.
Well location, depth and construction method restrictions are evaluated and well construction and use may be modified by MDH in these areas to prevent exposure to contaminated groundwater and ensure that a well does not become a conduit for contamination into adjacent formations. Groundwater monitoring data for the contaminant plume will be re-evaluated by the MDA staff until the SWCA is removed by the MDH.
Request Specific Information about a Site: To request information about a specific site, contact the Data Management Unit at 651-201-6698 with the MDA Project File Number, the name, and location of the site.
