Rennie Farm
Rennie Farm Update:
Current Status
- Hydrogeologic conditions on the Rennie Farm property and migration of 1,4-dioxane contamination have been extensively investigated, mapped, and accepted by the New Hampshire Department of Environmental Services (DES).
- A groundwater pump and treat system was approved by DES, began operation in January, 2017, and is operating effectively. The system removes 1,4-dioxane from groundwater within the source area and portions of the plume located on the Rennie Farm property, preventing its further movement off the property.
- In April, 2017, the United States Environmental Protection Agency authorized a permit to increase the rate of groundwater treatment and established water quality standards for the discharge of treated water.
- A Groundwater Management Permit (Permit) was issued by DES in August, 2017, establishing a long term water quality monitoring program for the site, including a total of 96 water quality monitoring locations (groundwater, surface water, and water supply wells). The Permit also establishes a groundwater management zone that includes the area of known contamination and a buffer area established to protect public health and to monitor groundwater quality.
- Water quality monitoring shows no expansion of the 1,4-dioxane plume. There have been no impacts to the more than 140 water supply wells tested to ensure the safety and address the concerns of our neighbors. Only one water supply well, 9 Rennie Road, has been impacted.
- Current sampling results indicate that there have been significant reductions in the concentration of 1,4-dioxane including a 78% reduction in concentration in the source area and an 81% reduction immediately downgradient of the source area on the Rennie property, based on December 2020 data.
- During 2020 Dartmouth constructed an expansion of the pumping well system used to capture 1,4-dioxane in groundwater off of the Rennie property. While not required by NHDES, the expansion of the system was constructed to accelerate the cleanup and provide additional protection of human health and the environment.
- The pumping wells constructed during 2020 are operating, with the rate of removal of 1,4-dioxane roughly 20 times greater than prior to the startup of the new wells.
Value Assurance Program (VAP)
- In February, 2017 Dartmouth announced its Value Assurance Program (VAP), which assures property owners in the defined Program Area (48 properties) that they will receive fair market value the for their property if sold within the 5 year program. Dartmouth will either buy the property at fair market value or pay the difference between an offer to purchase and the fair market value, as determined through an established listing and appraisal process.
- As of June 2021, Dartmouth has purchased 11 properties as part of the VAP. Of these properties, seven have been sold, and four parcels of land are held for future sale.
- Dartmouth expects to sell properties purchased as part of the VAP at a later date.
- In June 2021 Dartmouth announced that they would be extending the VAP until February 2027.
Background
- From the mid-1960s until 1978, a less than ½-acre area of the ~230 acre property, was used as a State licensed burial site for animal carcasses used in medical and other research, including testing using radionuclides.
- Dartmouth voluntarily decided to remove the animal carcasses, and the removal was completed during late 2011 under the approval of the New Hampshire Department of Health and Human Services, Radiological Health Section (RHS). During the removal unexpected chemical waste was encountered. DES was notified and the contaminated materials encountered were removed.
- During April 2012, analysis of groundwater samples detected 1,4-dioxane (a volatile organic compound [VOC] used in laboratories) at a concentration exceeding the New Hampshire groundwater standard of 3 micrograms per liter (ug/L). The 1,4-dioxane dissolved in groundwater and related to the unexpected chemical waste encountered during the 2011 excavation.
- No other contaminants have been detected in excess of NH Groundwater Standards.
- Working with the DES and consistent with State environmental requirements, Dartmouth conducted an extensive phased investigation and constructed a groundwater treatment system at the site related to the 1,4-dioxane. This work is focused on protecting human health and remediation of the 1,4-dioxane and will continue until the concentration of 1,4-dioxane meets the New Hampshire groundwater standard.
