Ecological Evaluation Technical Guidance - State of New Jersey

multiple reference area soils representative of the physical characteristics ofthe test soil will facilitate interpretation of the resultant data. Further guidanceon the use of reference area samples for soil toxicity tests are provided inAppendix H.To ensure meaningful comparisons of soil chemistry and toxicity test results,it is important that physical and chemical factors at the reference areaaffecting the site chemistry and bioavailability (e.g., grain size, TOC, redoxpotential, pH, concentrations of salts, nutrients, and chemicals) are similar tothe conditions at the site. In addition, habitat conditions at reference arealocations should be as similar as possible to ensure that receptors identified asappropriate for site conditions also might be exposed to reference areas. Ifsite conditions are heterogeneous, it may be necessary to select more than onereference area for evaluation to ensure that all possible variations areaddressed. In addition, established regional background contaminant levels,reflecting ambient soil or tissue concentrations based on monitoring datacollected from throughout a specified area over a given period might be usefulin select cases if reference area locations cannot be established for yourproject.In the event that an acceptable clean reference area cannot be found on-site, anoff-site local reference area location should be sampled. If an off-sitereference area is selected, it should be located within the same watershed andshould be of a similar habitat type, and differences in morphology should benoted. Any contaminant levels in the reference area should also be noted.6.2.3.2 Terrestrial Habitat Assessments and Community SurveysThe identification of terrestrial habitats within ESNRs and quantitativecommunity surveys are often overlooked components of the ERA. However,an understanding of the terrestrial environment at a site is a critical feature toaddressing problem formulation concerns with the extent of ESNRs, thepotential presence of threatened or endangered species, and the type ofecological receptors to be used in potential food chain modeling or soiltoxicity testing. Additionally, the evaluation of terrestrial habitats andcommunities can be used as a line-of-evidence as part of the riskcharacterization.Communities are defined as an interacting collection of plants and animalsinhabiting a given area. In many ERAs, the community assemblages will besimple or driven by early successional stages that are the result ofanthropogenic actions (e.g., clearing, landscaping, farming, or building). Insuch instances, a qualitative description of the types of plants and potentialwildlife inhabiting the area may be developed through a pedestrianreconnaissance of the site or AOC. Qualitative surveys such as this arefocused more on a species inventory. However, at other sites encompassing avariety of different ESNRs or community types, quantitative surveys may berequired to more adequately define the receptors that will be evaluated in theERA. In complex situations, quantitative surveys may be employed toEcological Evaluation Technical Guidance Document 64Version 1.2 8/29/12