EPA Research Partner Support Story: Contaminated groundwater from former battery demolition site entering neighborhood creek
Partner: Louisiana Department of Environmental Quality (DEQ)
Challenge: Contaminated groundwater from former battery demolition site entering neighborhood creek
Resource: Technical assistance and characterization studies for mitigating off-site acid and heavy metal impacts
Project Period: 2004 – Present
Past activities at the Delatte Metals Superfund site in Ponchatoula, Louisiana, involving processing spent lead-acid batteries and smelted lead plates have resulted in significant contamination of groundwater. Contaminants include sulfuric acid, lead, cadmium and nickel. The site borders a large creek that runs adjacent to a residential neighborhood. In order to mitigate impacts to the creek, a permeable reactive barrier (PRB), consisting of limestone and composted cow manure, was installed parallel to the creek to intercept the impacted groundwater and both neutralize the sulfuric acid and remove the heavy metals prior to entry of the groundwater into the creek.
“The permeable reactive barrier wall allows us to be protective of the waters of Selsers Creek. ORD’s assistance with the testing of the wall was essential. Our collaboration with our federal partner was key to completing this mission at Delatte Metals Superfund site, and we continue to cooperate with EPA and ORD on other issues at this site.” – Louisiana DEQ former Secretary Chuck Carr Brown, PhD
EPA ORD has been working with the Louisiana DEQ and EPA Region 6 (South Central) to evaluate the long-term performance of the PRB in preventing discharge of contaminants into the creek. Monitoring and evaluation―involving groundwater sampling for metals and geochemical parameters, hydraulic conductivity and flux measurements, and PRB core analysis―are being used to assess performance and identify potential issues impacting long-term performance.
The PRB has performed well for over 14 years with performance monitoring scheduled to continue in coordination with the Louisiana DEQ and EPA Region 6. The sulfuric acid is being fully neutralized, and metals are being effectively removed (e.g., Pb from 100 µg/L upgradient to <0.09 µg/L within the PRB and Cd from 66 µg/L to <0.07 µg/L). Observed gradual changes in geochemical parameter measurements suggest, as expected, that the effectiveness of the PRB will have a finite lifetime. Louisiana DEQ and EPA ORD will continue to monitor PRB effectiveness to determine if contaminant levels decrease to safe levels, sparing the cost of replacement.