LOUISIANA DEPARTMENT OF ENVIRONMENTAL QUALITY | Secretary Aurelia S. Giacometto
A DEPARTMENT OF THE STATE OF LOUISIANA
LDEQ has primary enforcement responsibility in Louisiana and its rules and regulations are as stringent as EPA’s.
It is the Department’s understanding that the new sewer project is funded by the state and is under the direction of the Grant Parish Police Jury.
The Department is not aware of any chemicals being pushed toward the Fairway East Subdivision. However, in-situ chemical oxidation (ISCO) for the treatment of groundwater contamination is being conducted on the Dresser facility property. The injected oxidant breaks down the TCE in groundwater to harmless byproducts thereby reducing the amount of TCE present.
The current remedial focus is on reducing TCE concentrations in groundwater at the source area where the highest impacts are located. These remedial actions will serve to reduce TCE concentrations in surrounding areas over time.
The LDEQ is not an expert on property valuation. The law and regulations require a responsible party to remediate the contamination to the legally required standard. LDEQ is supervising Dresser’s carrying out of that mandate. LDEQ’s role in the response actions is to oversee the investigation and remediation of the release and ensure that the work complies with LDEQ regulations.
The Department does not have sufficient information to provide a response to this question since no examples of remedial alternatives were provided. In general, selection of remedial alternatives is dependent upon numerous site-specific factors. However, just because a remedial alternative was effective at one site, does not mean it will be effective at all sites.
In-situ chemical oxidation (ISCO) is not being implemented along Austin Drive, therefore chemicals are not being injected at Austin Drive. ISCO is only being used on the Dresser property for groundwater remediation. Soil Vapor Extraction (SVE) is the technology being used along Austin Drive. This process pulls the vapors present in the subsurface back to the Dresser facility where the air stream is then passed through a granulated activated carbon unit which removes the chlorinated solvent vapors. The air stream is sampled and then discharged to the atmosphere.
The oxidants being injected into groundwater at the Dresser facility have a zone of influence that extends approximately 120 feet from the injection well. The oxidants rapidly react with TCE to break it down into harmless byproducts.
The time required for completion of groundwater remediation is dependent on many factors. Typically, groundwater remediation requires long periods of time for acceptable chemical concentrations to be achieved throughout a plume. As data becomes available from the ISCO monitoring system better estimates of time frames for completion of remedial actions at the Dresser facility and surrounding areas will be available.
Yes, initial groundwater monitoring of the ISCO system indicates that TCE concentrations in groundwater in the zone of influence are declining in response to the oxidant. In addition, the onsite soil vapor extraction system (SVE) has removed 2,417 pounds of chemical mass as of May 14, 2021, during the 313 days it has been in operation. The offsite SVE system has removed 49.9 pounds of chemical mass as of May 14, 2021, during the 51 days it has been in operation. All wells are sampled semi-annually in May and November. All of this data is available in LDEQ’s EDMS AI# 2920.
No, the permits in question cover sanitary discharges and an emergency discharge from containerized water stored in onsite tanks from stormwater accumulation in onsite excavations. This water was tested for the presence of chlorinated solvents prior to discharge to the surface water LPDES outfall near Jennifer’s Place. However, the findings in the diches along Austin Drive and the Highway 71/167 split are still under investigation.
The reports being referred to are bi-weekly reports and represent the most current data available. In some instances, the reports may not contain new information because additional sampling may not have occurred in that specific area.
There are plume defining wells around the entire groundwater plume including the Fairway East Subdivision.
A permeable reactive barrier is not a feasible alternative for this site due to the nature and extent of the groundwater plume present.
LDEQ does not know why this reading was so high, but it is inconsistent with all previous sampling results.