Scientists and engineers at E2 have considerable exprience in modeling the movement of a pollutant in and among multiple media. We have developed, tested, and applied several atmospheric dispersion, groundwater flow and transport, and surface water transport models in support of human and ecological risk assessments. We have also developed considerable expertise in propagating uncertainties through these models and conducting sensitivity analyses with them.

Air Disprsion Modeling. E2 has developed capabilities to model the movement of both neutrally and negative buoyant polluants in the atmosphere using various off-the-shelf and in-house-developed models. We have modeled the fate (speciation chemistry) and transport of I-131 using a in-house modified version of Gausian Plume model, parameterized it within an uncertainty analysis framework involving joint probability distributions for correlated parameters and a Markov Chain-based methodology for generating  hourly rainfall data, and successfuly implemented the model for a dose reconstruction project at the Oak Ridge National Laboratory site.

We have conducted a detailed validation study of models used to assess the release,  thermodynamics, atmospheric chemistry, and transport of UF6, which generates a negatively buoyant plume, for the US Nuclear Regulatory Commission.

We have modeled the atmospheric resuspension of contaminants in Ukrainian regions impacted by Chernobyl fallout for the BIOlogical MOdel Validation Study, sponsored by the International Atomic Energy Agency (IAEA). Our predictions provided some of the best matches to measurements among multiple predictions made by participating international scientists.

We have applied several commercially available models such as COMPLY, AIRDOS (CAP88), ISCST, ISCLT, and GENII to evaluate the potential for radiation exposures to members of the public from contaminated sites and proposed waste disposal facilities.

We possess the expertise and capabilities to model atmospheric fate and transport and gas- and aqueous-phase chemistries to simulate photochemical reactions in the atmosphere leading to acid formation and deposition.

Groundwater and Surface Water Flow and Fate and Transport Modeling. Scientists and engineers at E2 have conducted groundwater flow and fate and transport analyses and surface water fate and transport analyses in support of human and ecological risk assessments. We have used both screening-level and detailed approaches to model both vadose zone and saturated zone flows and transport.

Several models were applied to assess facility performance and long-term health impacts from releases of radionuclides from a proposed above-ground LLRW disposal facility in Nebraska; models included FEMWATER, MODFLOW, FEMWASTE, BLT, MOC, HELP, and CREAMS.

For the BIOlogical MOdel Validation Study, sponsored by the International Atomic Energy Agency (IAEA), the wash-off of radioactive isotopes from two experimental plots established subsequent to the April 1986 accident in the vicinity of the Chernobyl nuclear reactor was modeled. Predictions provided some of the best matches to measurements among multiple predictions made by participating international scientists.

A vadose zone model was developed and validated at field to assess the release rate of volatile organic contaminants into the air and leach rate of the contaminants to the groundwater under an uncertainty analysis framework.