Windsong Park, Inc. a (501(c)(3)) is redeveloping a former railyard in Florida. A sitewide remediation strategy was needed to convert this brownfield from industrial/commercial land use to recreational land use due to residual arsenic contamination in soil.
Geosyntec’s Scope of Services
Geosyntec collaborated on this multi-firm project team led by the design architectural firm, Sasaki, Inc. Our role included developing the soil remedial approach to work in concert with the recreational redevelopment with the focus of reducing the volume of soil needed for offsite disposal. Our plan included evaluation of historical soil data in context with the sitewide grading plan, addressing arsenic data gaps, determining excavation boundaries via real-time arsenic screening of soil using a hand-held X-Ray Fluoresecence (XRF) meter combined with laboratory analyses, backfill analytical testing of an adjacent former orange grove, and meeting with FDEP regulators frequently. The approach was based on subdividing BSP into 10 “exposure units” (EUs) based on the intended land use in the vicinity (e.g., play center, buildings, gardens, trails, etc.). Geosyntec calculated the upper 95% confidence limit of arsenic concentrations for the 0 to 0.5 and 0.5-2 ft depth interval using the Florida PRO-UCL statistical model. If the 95% UCL was above the recreational soil cleanup target level (SCTL) of 5.5 milligrams per kilogram (mg/kg), then virtual remediation was performed in each EU to identify isolated arsenic “hotspots” for removal with replacement of clean backfill until the 95% UCL was less than 5.5 mg/kg.
The soil graded during park construction and removed from the hotspots was consolidated into two mounds being built on the property to serve as topographic features to improve the viewshed at the Park. The mounds function as perpetual engineering controls with a 2 ft clean soil cap and contain roughly 250,000 cubic yards of soil and debris.
Additional follow-on tasks includes spring water sampling and loading analysis of a diffuse seeps within a spring corridor that is a key focal point of the Park design; data analysis of chemical samples collected by the Park of an area designed for a shallow lagoon; data analysis of sediment and surface water quality obtained from the adjacent Lake Bonnet by the City of Lakeland; and groundwater mounding analysis required by FDEP to evaluate the effects of the stormwater management system.
Geosyntec’s established reputation and relationship with state regulators played an integral part in the approval of the remedial plan by FDEP. Our historical data evaluation, soil delineation, spring water sampling, chemical samples and sediments analysis, stormwater management system evaluation, and complete remedial design resulted in a “provisional” No Further Action (NFA) designation by FDEP. The NFA will be finalized once building construction at the base of the mounds is completed and the final engineering control is in place.
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- Location: Lakeland, FL
- Client: Sasaki, Inc.
- Project Practice Areas: Environmental Management
- Type of Facility: Former Rail Yard
- Services Provided: Soil Remedial Design, Implementation of Soil Remediation, Statistical data analysis, Engineering control maintenance plan, Stormwater modeling, Regulatory negotiation
- Type of Work: Remedial Investigations
- Governing Regulation: State and local