user's guide and background technical document for the nevada ...

where:
THQ = Target hazard quotient of 1
BW = Body weight of adult (70 kg)
AT = Averaging time of resident (30 years)
EF = Exposure frequency (350 days/year)
ED = Exposure duration (30 years)
IRW = Drinking water ingestion (2 L/day)
RfDo
VF
=
=
Oral reference dose (chemical specific) (mg/kg-day)
Volatilization factor for water (0.5 L/m 3 )
RfCi = Inhalation reference concentration (chemical specific) (mg/m 3 )
*Inhalation part of equation only calculated for volatile organic chemicals
Table 1 provides the Standard Default Exposure Factors used in the preceding equations.
3.6 Development of Final Human Health Soil BCLs
Several values are compared in order to develop the final soil BCL. These include the
comparison of the health-based BCL to a maximum soil concentration of 100,000 mg/kg for the
less toxic chemicals, and to the soil saturation limit, the lower of which is used as the final BCL.
These equations are listed below.
Residential Soil BCL
If the contaminant is a solid, the following applies:
Eq. 27a BCL (mg/kg) = Minimum value from Eq. 7, Eq. 8*, or 100,000 mg/kg
*Equation 8 uses the Eq. 4 option.
If the contaminant is not a solid, then the following applies:
Eq. 27b BCL (mg/kg) = Minimum value from saturation, Eq. 7, Eq. 8*, or
100,000 mg/kg
*Equation 8 uses the Eq. 4 option.
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