Gaffney Road Areawide Investigation

Site Narrative

Description

Decades of commercial/industrial use and former dry cleaning operations along Gaffney Road, in the City of Fairbanks, has resulted in multiple areas of soil contamination and area-wide groundwater contamination by chlorinated hydrocarbons, primarily tetrachloroethylene (PCE) and its daughter products- trichloroethene (TCE) and dichloroethenes (DCE). Groundwater investigations from 1997 to 1999 used passive soil gas studies, temporary and permanent monitoring wells, and sewer line sampling to delineate what appeared to be two groundwater plumes above regulatory limits originating in the Gaffney Road area and extending downgradient, generally north-northwest. The smaller, eastern plume exceeded1500 feet while the longer, western plume exceeded 3000 feet in length. DEC's investigations indicate there are three sources of contamination: two historical dry cleaning operations and the sanitary wooden sewer lines that served this area. The wooden sewer lines may have received contaminants from former dry cleaners and redistributed them to down-gradient areas through failures in the line, regular leakage, or vapor migration across the pipe into the surrounding soil and water.

Public Health and Environmental Concerns

Perchloroethylene, or PCE is a common dry cleaning solvent that has contaminated the soil and groundwater. Two contaminated groundwater plumes containing PCE and its breakdown products, TCE and DCE extend from release locations on the eastern and western side of Cushman Street. Although no drinking water wells have been identified within the plume, irrigation and other private wells are known to exist in the area. The Gaffney Road area is provided with drinking water by Golden Heart Utilities, and a City of Fairbanks ordinance requires residences to hook up to public water supply if it is provided by the Utility. In addition to the contaminant movement in the groundwater, PCE is also volatile and can move from the soil and groundwater into the air, possibly traveling into buildings affecting indoor air quality. DEC is currently operating a sub-slab depressurization system to prevent vapor intrusion into affected buildings. DEC is also monitoring the movement and status of the groundwater plume and periodically monitors contaminant vapors in buildings near the plumes.

Current Status

DEC periodically samples approximately 30 groundwater monitoring wells located throughout the plumes. Contaminant concentrations in groundwater are monitored to determine if the plumes are expanding or decreasing in size, and to see how the concentrations of contaminants and breakdown products change over time. The groundwater plumes appear to be stable, safely separated from the water supply wells for City residents.

DEC has conducted multiple surveys of properties overlying the contaminant plumes to see if there are wells still in use that are used for drinking purposes. Several wells in the area are used for cooling water or irrigation, but none have been found that are used for drinking.

In 2010, DEC installed and operated a combined soil vapor extraction (SVE) and sub-slab depressurization (SSD) system to remove PCE from the soil at the largest release area behind the Good News Bible and Book Store. The SSD system also removed vapors from beneath the bookstore building so that they would not migrate into the building. Since its installation, the treatment system has removed a sufficient mass of contamination that, when coupled with natural attenuation processes in the groundwater, the largest plume appears to be stable and is anticipated to shrink in size over time. This remedial system was modified during 2016 where large rotary blowers were replaced with an indoor radon fan on the SSD system. In 2019, passively operated pressure differential valves were installed on many SVE wells. The SSD system continues to operate as a preventative measure for vapor intrusion into the bookstore, while the SVE wells remove soil vapors from the surrounding vadose zone. 

DEC has also sampled indoor air and/or soil gas beneath or adjacent to 22 buildings that are closest to the contaminant source areas and have the greatest risk of vapor intrusion.

Environmental Protection Agency EPA staff and contractors from RTI and Jacobs recently completed a yearlong study of indoor air quality in seven commercial and institutional buildings located over the Gaffney Road contaminated groundwater plume. The EPA-led team investigated whether volatile organic compounds in the contaminated soil or groundwater are entering buildings. Samples were collected from indoor air in the commercial buildings as well as the soil gas under their foundations, to look for PCE, TCE and naturally occurring radon. The preliminary results suggest that PCE, TCE and/or radon is entering at least four of the seven buildings at detectable concentrations. Those concentrations were in most cases below target levels published by DEC. The concentrations varied significantly over the yearlong study period as is typical for vapor intrusion sites. The individual results have been communicated to the owners/occupants of the buildings.

The EPA, RTI, and Jacobs developed a new concept called “soil gas safe communities” to quickly identify indoor contaminants of concern that may be entering buildings from contaminated soil gas beneath homes and buildings. This approach used real-time radon detectors, provided free to homeowners, to indicate when vapor intrusion into the home is highest, so that samples for volatile organic compounds can be taken at the most important times. The results were then used to inform health and safety risks at a community scale and identify actions residents can take to improve indoor air quality. Visit the Soil Gas Safe Community project website for more information. 

What's Next

DEC will continue to monitor the groundwater in the contaminant plumes, as well as soil gas in locations above the groundwater plumes and adjacent to buildings at risk to vapor intrusion. DEC will also continue to evaluate vapor intrusion into buildings above the groundwater plume.

What can you do?

Please contact the DEC project manager at the number listed at the top of this page to report if you have a well on your property and what you use it for. Please avoid contact with any groundwater from the contaminant plume. Wells used for irrigation can spread contamination and expose people to contamination through volatilization. Please do not disturb any sampling activities occurring in the vicinity. Some soil gas sampling occurs over a period of several days so the sampling equipment may be left unattended.

The EPA led team of the Soil Gas Safe Community project is seeking more volunteer homes in the Gaffney Road area to schedule a free soil gas and indoor air quality screening of their properties to assess the potential for indoor air health impacts from the existing soil vapor plume.  The project team can be contacted at soilgassafe@rti.org. 

More Information

View the contaminated site database entry for more detailed information and documents related to the cleanup process. 

Information on PCE, TCE, and other contaminant health effects can be found at the Agency for Toxic Substances and Disease Registry website

Contact the Soil Gas Safe Community Project at soilgassafe@rti.org.

Vapor Intrusion Information:

• DEC vapor intrusion page
• EPA vapor intrusion page