As one of the first states to introduce a PFAS Monitoring Plan, the Minnesota Pollution Control Agency (MPCA) is providing a blueprint that others might follow when assessing how to monitor and document the use of these persistent chemicals.
The PFAS Monitoring Plan outlines the MPCA’s intent for a wide range of facilities to document their use or receipt of PFAS-containing materials and conduct PFAS sampling. The monitoring requested by the MPCA will vary by facility and may include testing under one or more of the five programs identified in the PFAS Monitoring Plan: air, wastewater, industrial stormwater, solid and hazardous waste, and remediation.
For now, the monitoring requested under the air, wastewater, industrial stormwater, and solid and hazardous waste programs will be focused on the 379 facilities the MPCA identified when the PFAS Monitoring Plan was released in March 2022. The remediation program will manage facilities covered under the PFAS Monitoring Plan for sites participating in the Brownfield or Superfund programs.
Facilities targeted by the MPCA will be asked to monitor their air emissions for PFAS in 2023 and report the results in the air emissions inventory report due April 1, 2024. Similar monitoring and reporting will be required every third year thereafter. The MPCA expects most facilities to calculate emissions by using a material balance and/or emission factor approach, or by completing a stack test.
The MPCA indicated it will also ask a subset of these facilities, including waste-to-energy plants, to collect and analyze air samples for PFAS during their next stack-testing event. Facilities will be responsible for all costs associated with PFAS sampling requested under the PFAS Monitoring Plan.
Under the wastewater program, participating municipal and industrial wastewater treatment facilities will be asked to conduct a minimum of four quarterly monitoring events. The approach and timing of the four quarterly monitoring events will vary for municipal and industrial facilities.
Municipal wastewater treatment facilities will be asked to monitor influent and evaluate upstream customers that could be contributing PFAS in their influent. After conducting two quarterly PFAS monitoring events, the municipal wastewater treatment facilities will pause sampling for six months to work with PFAS contributors on ways to reduce PFAS concentrations in the wastewater the municipal facility is receiving. The municipal treatment facilities will then conduct two additional quarterly monitoring events to measure any reduction of PFAS in the water they are receiving.
Industrial wastewater treatment facilities will initially be asked to monitor their internal process water quarterly for one year. During the first six months, they will develop an inventory of potential PFAS sources, with the expectation that they will reduce or eliminate these sources by the end of the one-year period. The MPCA expects PFAS monitoring at the industrial wastewater treatment facilities to begin during the second half of 2022 or first half of 2023.
Industrial Stormwater Program
The MPCA’s industrial stormwater program will focus initially on airports, chrome plating operations, automotive shredding facilities and other industrial stormwater sources that are potential PFAS contributors but are not included in one of the other PFAS Monitoring Plan programs. Beginning this year, these facilities will be asked to prepare a PFAS inventory and collect industrial stormwater samples for PFAS over three quarters. The number of sampling locations will vary according to the facility layout and existing stormwater monitoring locations.
While samples will be analyzed for all available PFAS compounds for the laboratory method used, this particular program will initially focus on perfluorooctane sulfonic acid (PFOS) concentrations. The MPCA chose PFOS because it is believed by the MPCA to drive health-related risks in many scenarios.
The MPCA has established a tiered set of PFOS response thresholds that will trigger follow-up action. For example, a facility with PFOS concentrations greater than 10 nanograms per liter in its stormwater will need to develop and submit a PFAS Source and Exposure Reduction Plan. The timetable for submitting that plan will depend on the magnitude of the exceedance. As information is gathered, the MPCA suggests it may revisit or add to the thresholds.
Solid and Hazardous Waste Program
Under the solid waste and hazardous waste program portion of the PFAS Monitoring Plan, the MPCA will ask the identified landfills and organic compost facilities to add PFAS sampling to their groundwater monitoring program. The MPCA intends to request PFAS monitoring at facilities covered under this program over the next two years, starting with those it estimates pose highest potential risk to human health receptors.
Some exceptions are possible for lined landfills with leachate collection systems. Upon request, the MPCA may initially allow those landfills to sample their leachate. Pending the results and other risk factors, PFAS sampling may later be added to these landfills’ groundwater monitoring plans.
Affected landfills will also be asked to update plans associated with their operating permits, documenting the addition of and methods used for PFAS sampling. The MPCA is proposing to review and approve those changes prior to the first groundwater sampling event. To account for seasonal variation, PFAS sample collection will be conducted three times annually. After comparing the groundwater monitoring results to the intervention limits, the MPCA intends to work with individual landfills to determine appropriate next steps.
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This post is the second in a series looking at each of the monitoring programs outlined in the new PFAS Monitoring Plan released by the MPCA. Look here for more on the continuing development of the plan and how its requirements could impact the operation of facilities in Minnesota. Other posts in the series: