Due diligence performed by Geosyntec for a former lease on behalf of the property owner indicated several potential Recognized Environmental Conditions (RECs) on site that warranted further evaluation. Geosyntec completed due diligence activities with the goal of managing the site assessment and subsequent remediation of chlorinated pesticides within the guidance of the Georgia Hazardous Sites Response Act (HSRA) and Georgia Hazardous Site Inventory (HSI). Once a site is listed on the HSI, significant costs can be incurred for regulation-required delineation of contaminants of concern to background concentrations (non-detect in the case of pesticides). Geosyntec successfully managed the project to avoid a HSI listing.
Geosyntec's Scope of Services
Initial sampling completed by Geosyntec indicated the presence of chlorinated pesticides in site soils at concentrations exceeding HSRA Notification Concentrations (NCs). In order to mitigate the regulatory reporting requirement, Geosyntec completed fast-track delineation sampling and soil excavation within the 30-day Georgia Environmental Protection Division (EPD) constraint. Direct push technology (DPT) was utilized to collect over 77 soil samples and delineate soils with chlorinated pesticides exceeding the NCs. Geosyntec completed non-hazardous and hazardous waste profiles, developed excavation plans, and provided construction oversight for the remedial soil excavation. Approximately 1,300 tons of non-hazardous waste and 100 tons of hazardous waste soils were excavated, transported off site, and disposed of in permitted facilities. Twenty-three post-excavation soil samples were collected to document that soil had been adequately addressed, eliminating the HSRA obligation reporting for soils.
Geosyntec also conducted an extensive groundwater investigation at the site. Ten shallow monitoring wells (35 ft.) and one deep monitoring well (100 ft.) were installed on the property to delineate chlorinated pesticides in groundwater. Geosyntec also completed a detailed water supply well survey to identify active wells within a 3-mile radius along with well screen depths and withdrawal zones/aquifers. The delineation efforts, coupled with the detailed water supply well survey were utilized to demonstrate that with the removal of the source materials, the low concentrations of pesticides detected in the groundwater, and natural attenuation, contamination would not pose a risk to off-site water supply wells. On behalf of the property owner, Geosyntec prepared a HSRA Notification Package associated with the groundwater investigation.
Geosyntec successfully completed fast-track soil delineation and remediation that removed chlorinated pesticide concentrations above HSRA NCs, thereby eliminating potentially expensive and regulatory-required additional sampling and reporting as well as a possible HSI listing. Geosyntec was able to demonstrate that the minimal impacts to groundwater and removal of the source material mitigated threats to human health and the environment and achieved a No Further Action (NFA) status from the EPD thereby eliminating an expensive groundwater remediation program and future remedial costs.