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    RISC Description

    Key New Features in RISC Version 4

    RISC 4 Features

    RISC 4 System Requirements

RISC Description

RISC 4 is a software package for performing fate and transport modeling and human health risk assessments for contaminated sites. A unique feature of RISC 4 is its ability to perform a backward risk calculation as well as the conventional forward risk calculation. The backward risk calculation in RISC 4 refers to calculating a cleanup level for an input value of risk. Fate and transport models are available in RISC 4 to estimate receptor point concentrations in groundwater and indoor and outdoor air. No other RISK package offers all this! RISC 4 can be used to estimate the potential for adverse human health impacts (both carcinogenic and non-carcinogenic) from up to nine exposure pathways. Additional pathways and other non-human health impacts may be considered in future revisions of RISC.

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Key New Features in RISC Version 4

Version 4.0 of RISC has new features that give it even greater flexibility in assessing risk for the following scenarios:

• Irrigation pathways, i.e. water used for gardening but not for indoor usage

• Vegetables grown in contaminated soil

• Two new vapor models , where the vapors are allowed to biodegrade during transport through the unsaturated zone

• Models for surface water and sediment contamination from impacted groundwater and direct comparison with relevant national standards for these media

• The use of groundwater MCLs (maximum concentration levels) and surface water concentrations in addition to acceptable risk levels as the criteria for back-calculating clean-up targets

• The ability to calculate a site-specific target level (SSTL) for a TPH mixture using the site-specific measured concentrations of the TPH fractions detected in the soil

We feel confident that RISC Version 4.0 provides the latest and most complete package for calculating risk to human health and surface water. This version has been peer-reviewed by Arcadis, Geraghty and Miller in Cambridge, UK. Their review is included in Appendix R

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RISC 4 Features

• A customizable chemical database with 82 chemicals

• An Excel spreadsheet based on the RBCA algorithms that can be used to replicate the tiered RBCA process

• A detailed user's manual with three in-depth example problems

• The ability to determine risk-based TPH (total petroleum hydrocarbon) targets using the TPH fractions proposed by the U.S. Air Force led TPH Working Group

• The ability to calculate additive risk due to multiple pathways, compounds and receptors (such as a resident exposed as both a child and an adult)

• A Monte Carlo capability for probabilistic risk evaluation

• Fate and transport models that distinguish between presence and absence of phase-separated product (NAPL) in the source zone

• Ingestion of soil

• Dermal contact with soil

• Ingestion of groundwater

• Dermal contact with groundwater

• Inhalation in the shower

• Inhalation of outdoor air

• Inhalation of indoor air

• Ingestion of surface water

• Dermal contact with surface water

• Johnson and Ettinger indoor air model

• Vadose zone model

• Saturated zone model

• Volatilization from groundwater to indoor and outdoor air

• Outdoor box model

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RISC 4 System Requirements

Hardware Requirements

• Penium or higher

• 10MB RAM

• 12MB free disk space

• MS Windows 9x/2000/XP or higher

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