Ecological Evaluation Technical Guidance - State of New Jersey

ingested, air inhaled, or material applied to the skin is known as the potentialdose. A critical aspect of food chain modeling is the identification and use ofexposure factors. These factors represent species-specific parameters relatedto food and water ingestion, body weight, home range, foraging range, anddiet composition.Exposure pathways that generally are of concern for ROI when conductingfood chain modeling for an ERA include the following: Ingestion of contaminated food (plants or prey), particularly forcontaminants with potential to bioaccumulate or biomagnify; Ingestion of contaminated water; and Ingestion of contaminated soil or sediment.Although not frequently assessed, inhalation of contaminated airborneparticles and vapors, and dermal absorption can also be considered, but aregenerally considered to be negligible. The majority of exposure is typicallycalculated using the oral exposure pathway. A series of equations are used toquantify the uptake by this pathway. The total exposure experienced by aparticular ROI is the sum of the exposures to these pathways for each sourceand is generally described as the following:E total = E food + E water + E incidental soil/sediment ingestionWhere:E total = total exposure from all pathwaysE food = exposure from food consumptionE water = exposure from water consumptionE incidental soil/sediment ingestion = exposure from soil or sediment consumptionLiterature reference values for the independent parameters in each exposuremodel equation should always be supported by literature citations or sitespecificinformation. Useful sources of exposure factors and information fordeveloping soil, sediment, food, and water ingestion pathways are the WildlifeExposure Factors Handbook (USEPA, 1993a) and Estimating Exposures ofTerrestrial Wildlife to Contaminants (Sample, et al, 1994).For exposure estimates to be useful in the assessment of risk to wildlife, theestimates should be expressed in terms of a body weight-normalized dailydose (e.g., milligrams of contaminant per kilogram of body weight per day(mg/kg/day)). Exposure estimates expressed in these units are then comparedto toxicological benchmarks for wildlife or to doses reported in the scientificliterature. Estimation of the daily contaminant dose to a particular species foreach exposure pathway can be calculated by the general intake equationdefined as:ADD = CM*IR*FI*AF*BW -1Where:ADD = Average Daily Dose (mg/kgBW-day)Ecological Evaluation Technical Guidance Document 38Version 1.2 8/29/12