New Jersey Administrative Code
Title 7 - ENVIRONMENTAL PROTECTION
Chapter 26D - REMEDIATION STANDARDS
Appendix 3
DEVELOPMENT OF SOIL REMEDIATION STANDARDS FOR THE INHALATION EXPOSURE PATHWAY
This appendix describes the procedures and equations used by the Department to develop the soil remediation standards for the inhalation exposure pathway as contained at N.J.A.C. 7:26D Appendix 1, Tables 3 and 4. This appendix is also used to develop interim soil remediation standards for the inhalation exposure pathway pursuant to N.J.A.C. 7:26D-6 and for updating soil remediation standards for the inhalation exposure pathway pursuant to N.J.A.C. 7:26D-7.
If a calculated soil criterion for a contaminant for the inhalation exposure pathway is greater than its soil saturation limit for the volatile portion of the equation, the volatile component of the equation is not applicable in the development of the soil criterion for the inhalation exposure pathway.
If the calculated soil criterion for a contaminant for the inhalation exposure pathway is greater than one million parts per million, a soil remediation standard for that contaminant for the inhalation exposure pathway does not apply.
If the calculated soil criterion for a contaminant for the inhalation exposure pathway is less than the soil reporting limit for that contaminant, the soil remediation standard for that contaminant for the inhalation exposure pathway defaults to the soil reporting limit.
Equations 1 through 7 below are derived from the USEPA, Regional Screening Levels (RSLs)--Equations (November 2018). A detailed explanation of the derivation of Equations 1 and 2 is contained at N.J.A.C. 7:26D Appendix 12.
Equation 1--Carcinogenic Inhalation Human Health-Based Criteria
| Parameter | Definition | Units | Default |
| Inhc | Carcinogenic inhalation human health-based criterion | mg/kg | Chemical specific |
| TR | Target cancer risk | unitless | 1 x 10-6 |
| AT | Averaging time | days/year | 365 |
| LT | Lifetime | years | 70 |
| IUR | Inhalation unit risk factor | (µg/m3)-1 | Chemical specific |
| EF | Exposure frequency | days/year | 350 (Residential) 225 (Nonresidential) |
| VF | Soil-to-air volatilization factor | m3/kg | Chemical specific |
| PEF | Particulate emission factor | m3/kg | 1.67 x 109 (Residential) 1.64 x 109(Nonresidential) |
| ED | Exposure duration | years | 26 (Residential) 25 (Nonresidential) |
| ET | Exposure time | hours/day | 24 (Residential) 8 (Nonresidential) |
Equation 2--Noncarcinogenic Inhalation Human Health-Based Criteria
| Parameter | Definition | Units | Default |
| Inhnc | Noncarcinogenic inhalation human health-based criterion | mg/kg | Chemical specific |
| THQ | Target hazard quotient | unitless | 1 |
| AT | Averaging time | days/year | 365 |
| EF | Exposure frequency | days/year | 350 (Residential) 225 (Nonresidential) |
| ED | Exposure duration | years | 26 (Residential) 25 (Nonresidential) |
| ET | Exposure time | hours/day | 24 (Residential) 8 (Nonresidential) |
| RfC | Reference concentration | mg/m3 | Chemical specific |
| VF | Soil-to-air volatilization factor | m3/kg | Chemical specific |
| PEF | Particulate emission factor | m3/kg | 1.67 x 109 (Residential) 1.64 x 109(Nonresidential) |
Equation 3--Volatilization Factor (VF)
| Parameter | Definition | Units | Default |
| VF | Soil-to-air volatilization factor | m3/kg | Chemical specific |
| Q/C | Inverse concentration at center of source | (g/m2-s)/ (kg/m3) | 86.6 (Residential) 85 (Nonresidential) |
| DA | Apparent diffusivity | cm2/s | Chemical specific |
| T | Exposure interval | seconds | 8.20 x 108 |
| pb | Dry soil bulk density | g/cm3 | 1.5 |
Equation 4--Apparent Diffusivity (DA)
| Parameter | Definition | Units | Default |
| DA | Apparent diffusivity | cm2/s | Chemical specific |
| [THETA]a | Air-filled soil porosity | Lair/Lsoil | 0.18 |
| Di | Diffusivity in air | cm2/s | Chemical specific |
| H' | Henry's law constant | unitless | Chemical specific |
| [THETA]w | Water-filled soil porosity | Lwater/Lsoil | 0.23 |
| Dw | Diffusivity in water | cm2/s | Chemical specific |
| n | Total soil porosity | Lpore/Lsoil | 0.41 |
| pb | Dry soil bulk density | g/cm3 | 1.5 |
| Kd | Soil-water partition coefficient | cm3/g | Chemical specific |
Equation 5-Soil--Water Partition Coefficient (Kd)
| Parameter | Definition | Units | Default |
| Kd | Soil-water partition coefficient | cm3/g | Chemical specific |
| Koc | Soil organic carbon-water partition coefficient | cm3/g | Chemical specific |
| foc | Organic carbon content of soil | g/g | 0.002 |
Equation 6--Particulate Emission Factor (PEF)
| Parameter | Definition | Units | Default |
| PEF | Particulate emission factor | m3/kg | 1.67 x 109(Residential) 1.64 x 109(Nonresidential) |
| Q/C | Inverse concentration at center of source | (g/m2-s)/(kg/m3) | 86.6 (Residential) 85 (Nonresidential) |
| v | Percent vegetative cover | percent | 50 |
| Um | Mean annual wind speed | m/s | 4.56 |
| Ut | Equivalent threshold value of wind speed at 7 m | m/s | 11.32 |
| F(x) | Function dependent on Um/Ut derived using Cowherd et al. (1985) | unitless | 0.159 |
Equation 7--Soil Saturation Limit (Csat)
| Parameter | Definition | Units | Default |
| Csat | Soil saturation limit | mg/kg | Chemical specific |
| S | Water solubility | mg/Lwater | Chemical specific |
| pb | Dry soil bulk density | g/cm3 | 1.5 |
| Kd | Soil-water partition coefficient | cm3/g | Chemical specific |
| [THETA]w | Water-filled soil porosity | Lwater/Lsoil | 0.23 |
| H' | Henry's law constant | unitless | Chemical specific |
| [THETA]a | Air-filled soil porosity | Lair/Lsoil | 0.18 |
