Health-Based Guidance Development Process
Issuing and Using Guidance
The Minnesota Department of Health (MDH) protects public health by adopting administrative rules establishing Health Risk Limits for groundwater and Health Risk Values for ambient air.
MDH also develops other guidance for air and water to advise state agencies on the assessment of health risks from exposure to environmental contaminants. MDH develops these guidelines in two forms:
- Health Based Values (HBVs) are developed at the request of state agencies or through a nomination process. For chemicals that have been detected in groundwater, MDH recommends using the most recently developed HBV until the value is promulgated as an HRL. If an HBV has been calculated for a chemical that has not been detected in groundwater, an HBV will not be promulgated as an HRL. The studies used to develop these values are of the same quality as those used for HRLs and HRVs.
- Risk Assessment Advice (RAA) is developed at the request of state agencies for chemicals that lack adequate data to develop an HBV. Because RAA is typically based on more limited data, it contains greater uncertainty.
The process outlined below focuses on groundwater and ambient air guidance. It does not address advice developed by the MDH Fish Consumption Advisory Program.
An HRL or HRV is the concentration of a chemical in groundwater or ambient air, respectively, which is unlikely to pose a health risk to the general public. These values are designed to protect vulnerable subpopulations such as infants and children. MDH may also develop health-protective levels for mixtures of chemicals that have a common health effect. MDH develops these levels through a formal administrative rulemaking process that might take several years to complete. The public and other stakeholders also participate through a series of public meetings and a formal comment process.
To respond to a request for guidance for a chemical that does not have an HRL or HRV, MDH develops an HBV or RAA.
To remain current in its mission to protect public health, MDH incorporates new, up-to-date information into its risk assessment methods. When new methods or toxicity information become available between formal rule adoptions, MDH may incorporate this information into guidance.
MDH selects chemicals for review based on requests from other programs within MDH; from other state agencies, such as the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Agriculture (MDA); and from the public through the Contaminants of Emerging Concern program.
MDH keeps interested parties informed of the review process. MDH posts a list of chemicals under review and invites interested parties to submit data that may be useful in the review. MDH also communicates with interested parties via the GovDelivery email subscription service. Notifications of new chemical reviews specify a period of time, typically at least 30 days, for the public to submit data for consideration.
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When developing guidance, MDH uses the methodology contained in the HRL or HRV Rules unless it determines that public health would be better protected by using updated methods. If the available toxicity information is not sufficient, MDH may elect to develop qualitative RAA (e.g., narrative description of toxicity relative to a similar chemical). If there is insufficient scientific information, MDH may decline to issue guidance of any kind.
When MDH develops new guidance as HBV or RAA based on the most recent methodology and scientific information, it is recommended that risk assessors and risk managers follow new guidance instead of a previously established HRL or HRV (this is referred to as dual guidance). Please refer to the MDH Dual Guidance for Drinking Water Methodology for more information about dual guidance.
Issuing and Using Guidance
MDH releases an HBV or RAA to the public by posting the guidance and accompanying information on the MDH Guidance web page (also see: Air Values Table and Human Health Based Water Guidance Table). MDH notifies subscribers via the GovDelivery email subscription service. While MDH always welcomes public comments, there is no formal public comment period for HBVs and RAA.
RAA intended for statewide use is included in MDH’s health-based guidelines table. MDH may develop RAA for specific conditions or specific sites when conditions unique to the location or exposure setting warrant such a site- or condition-specific response. RAA developed for specific conditions should not be applied to other sites without consulting MDH. MDH does not post site-specific RAA in its health-based guidelines table.
In a commitment to maintaining accurate and current guidance values, all chemical guidance derived from 2008 to present using the methods described in the 2008 SONAR are re-evaluated on an approximately five year schedule. A chemical may be selected for re-evaluation based on, but not limited to, the following:
1) substantive new toxicological information;
2) programmatic need for an updated value, including selection of the chemical for rulemaking; and/or
3) change in MDH risk assessment methodology.
Guidance values that change as a result of re-evaluation will be updated on the Human Health-Based Water Guidance Table.