Main Features Include:

• Estimate human health risk from exposure to contaminated media (air, water, soil).
• A customisable chemical database with 82 chemicals
• 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 he 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

In particular, RISC v4 has new features that give it even more flexibility in assessing risk for the following scenarios:

• Irrigation pathways, i.e. water used for gardening, and vegetables grown in contaminated soil
• Two new vapour models, in which the vapours are allowed to biodegrade during movement through the unsaturated zone
• Models for surface water and sediment contamination from impacted groundwater with 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

Exposure Pathways Include:

• 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

Fate and Transport Models Include:

• Johnson and Ettinger indoor air model
• Volatilisation from groundwater to indoor and outdoor air
• Outdoor box model
• Unsaturated zone model
• Saturated zone model