An assessment was conducted at an abandoned natural gas processing plant. The assessment documented elevated concentrations of heavy metals including mercury and lead. Kleinfelder was tasked with delineating the areas in which concentrations of metals were not protective for human exposure and to develop and execute a remediation plan.
Based on the assessment results, elevated metals concentrations were present in surface soils in an area of the former plant that had been redeveloped for residential use. Prolonged exposure to the contaminated soils could be harmful to the health of individuals in the area. Contaminated soil was present in an area with an extensive network of abandoned piping.
More detailed delineation of the contaminated surface soil was completed in the area of residential development. The data was used to develop a remediation plan for removal of the impacted soil, including both horizontal and vertical extent of soil to be removed. Kleinfelder provided oversight for a third-party contractor during soil excavation and removal. Verification soil sampling was conducted based on a grid pattern and expedited sample analysis was obtained to avoid unnecessary delays. Where necessary, additional excavation and removal was completed.
After completion of the soil removal action, remaining concentrations of lead and mercury were documented to be less than the standards established to be protective of human exposure. The area was backfilled with clean fill material and restored to its original elevation, thereby ensuring the health of individuals in the area.