Environmental Background
Based on available records, Mercury had been released to soils surrounding a concrete pad located onsite. AGES was contracted by a natural gas industry client to determine if soils were affected and if so, design and implement remedial actions.
Mercury-Impacted Soil Remediation
Soil Sampling
To determine the extent of affected soil under a concrete pad and surrounding area, AGES collected soil samples at various depths for analysis of Mercury. Mercury was detected in one (1) surface soil sample above the state of Kentucky residential action level (1.8 mg/kg). Based on this result, remedial action was required to address soils at the site.
Soil Removal Action with Lumex Field Screening
The remedial action at this site consisted of excavating soil from dimensions of 19 feet x 8 feet x 1 foot deep at the location of the Mercury-affected soil sample. All field work was conducted in accordance with standard industry practices. Existing concrete was removed to allow for excavation of underlying soils. The actual excavation was completed using a rubber tire backhoe. Excavated soil was loaded directly into trucks and transported to an approved landfill. After the excavation was complete, it was lined with plastic and backfilled with limestone gravel.
To guide the excavation, soil samples were screened for Mercury with a Lumex 915+ Mercury Analyzer with an oven attachment. Soil was excavated until the Lumex results indicated that Mercury levels were less than the action level. The original proposed size of the excavation (20’ x 10’ x 1 foot deep) was reduced based on the results of the Lumex screenings.
AGES collected confirmation soil samples to ensure that all affected soil had been removed. Mercury was not detected above the state of Kentucky residential action level (1.8 mg/kg) in any of the confirmatory samples. Therefore, no further action was required.
Special Project Features
1.) By using the Lumex to screen soil for Mercury, the volume of excavated soil was limited and waste disposal costs were reduced.
2.) The Lumex allowed for the soil excavation to be completed during one (1) mobilization. This fixed project mobilization costs and allowed for adherence to a tight project schedule.
