Ecological Evaluation Technical Guidance - State of New Jersey

decision making and implementation. RMDs should reduce ecological risks to levelsthat will result in the recovery and maintenance of healthy local populations andcommunities. In some instances, the proposed remedy may cause more ecologicaldamage then leaving the contaminant in place, particularly where rare or sensitivehabitats exist because of widespread physical destruction or alteration of the habitatthrough excavation or in situ treatment; however, leaving persistent and/orbioaccumulative contaminants in place may cause an ongoing source of contaminantexposure (USEPA, 1999a). In addition, the proposed remedial action may not beachievable because of technical impracticability.RMDs consider the present and predicted value of the affected ESNRs, and thebeneficial and detrimental effects on the ESNRs’ value with implementation of thepotential remedial activities. The key components to consider during the RMD are(1) that impaired habitats can provide some valuable ecological benefit (e.g. foodsource, breeding, rearing, and shelter), (2) the ecosystem extends beyond theperimeter of the impaired area, and (3) reduction in ecological benefits in one area ofthe ecosystem may be offset by a corresponding increase in ecological benefits inanother part of the ecosystem. Restoration activities should exceed the futuredecreased ecological benefits associated with the continued exposure to COPECs orany remedial activities. All RMDs must be approved by NJDEP (N.J.A.C. 7:26E-4.8(c)3). Examples of RMDs are noted in the following text.The following is presented solely to serve as an example of one project’s balancing ofremedial actions and preservation of habitat. Other methods of balancing these goalsmay be used on a site-specific basis.A firing range is located within a 100-acre mature forested wetland, which iscontiguous with another 500 acres of forested wetland, emergent wetland and uplandhabitat. Lead levels exceeding 200,000 ppm have been recorded in surface soils.Contaminated soil depths range from six inches to 30 inches. Based on site-specificBAFs for the earthworm, an ecological risk-based remediation goal of 300 ppm hasbeen established for lead based on the woodcock as the higher trophic level receptor.To achieve an average of 300 ppm of lead in the soil of the impacted wetland area,over 90 acres of the wetland would have to be destroyed and excavated, and clean fillwould have to be imported to re-establish the grade and replant. Historically, thesuccess of re-establishing mature forested wetlands in New Jersey is limited.According to a 2002 report, “on average, 92% of proposed emergent wetland acreagewas achieved, while 1% percent of proposed forested wetland acreage was achieved(NJDEP, 2002).”Therefore, an RMD was made to reduce the number of acres of habitat destroyedwhile still reducing risk and enhancing the habitat to add value to the ecologicalbenefits. A graph was established for the two areas of the ESNR with the highestlead levels in soil (see Figure 9-1). The volumetric reduction in total lead(concentration and volume of surficial lead removed) was plotted on the Y-axis andthe number of acres destroyed was plotted on the X-axis (Figure 9-1). By examiningthese graphs, it was determined that by removing soil in the most highly contaminatedareas and replacing these soils with noncontaminated fill, a 93 percent reduction inexposure risk (volumetric reduction in total lead) could be attained with onlyEcological Evaluation Technical Guidance Document 85Version 1.2 8/29/12