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Calcimator

Risk-Based Screening Level Calculator

Calculate risk-based soil and groundwater screening levels using EPA RSL methodology.

Inputs

Results

Soil screening level (mg/kg)

17.87

GW screening level (µg/L)

1.79

Soil cancer RBSL (mg/kg)17.87
Soil non-cancer RBSL (mg/kg)1,460
GW cancer RBSL (µg/L)1.79
GW non-cancer RBSL (µg/L)146
Soil driver (1=cancer, 0=non-cancer)1
GW driver (1=cancer, 0=non-cancer)1
How to Use This Calculator
  1. Enter the oral slope factor and oral reference dose from EPA's IRIS database for your contaminant.
  2. Set target cancer risk (typically 1E-6) and target hazard quotient (typically 1.0).
  3. Select land use type (residential or commercial/industrial) to apply appropriate exposure factors.
  4. Review soil screening levels for cancer and non-cancer endpoints and the protective screening level.
  5. Compare calculated screening levels to site analytical data to determine if remediation is required.

How the result changes with Oral slope factor ((mg/kg-day)⁻¹)

Oral slope factor ((mg/kg-day)⁻¹)Soil screening level (mg/kg)GW screening level (µg/L)
100.10.01
350.030
650.020
900.010

What each input means

Oral slope factor ((mg/kg-day)⁻¹)
Cancer slope factor for oral pathway. Benzene = 0.055, TCE = 0.046. From EPA IRIS database.
Oral reference dose (mg/kg-day)
Non-cancer reference dose. Benzene = 0.004, Toluene = 0.08. From EPA IRIS.
Target cancer risk
Acceptable cancer risk level. 1e-6 (1 in a million) is standard; some states use 1e-5.
Target hazard quotient
Acceptable hazard quotient for non-cancer effects. Standard is 1.0.
Land use (0=residential, 1=commercial)
Residential uses more conservative (protective) exposure assumptions.
Body weight (kg)
Standard adult body weight. EPA default is 70 kg for adults.

What each result means

Soil cancer RBSL (mg/kg)
Cancer-based soil screening level.
Soil non-cancer RBSL (mg/kg)
Non-cancer soil screening level based on reference dose.
Soil screening level (mg/kg)
Protective soil screening level (lower of cancer and non-cancer).
GW cancer RBSL (µg/L)
Cancer-based groundwater screening level.
GW non-cancer RBSL (µg/L)
Non-cancer groundwater screening level.
GW screening level (µg/L)
Protective groundwater screening level.
Soil driver (1=cancer, 0=non-cancer)
Which risk endpoint drives the soil screening level.
GW driver (1=cancer, 0=non-cancer)
Which risk endpoint drives the groundwater screening level.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Oral slope factor ((mg/kg-day)⁻¹) = 0.055, Oral reference dose (mg/kg-day) = 0.004, Target cancer risk = 0.000001, Target hazard quotient = 1 = 6 input(s) provided
  2. Calculate Soil screening level
    Soil screening level = min(soilCancer, soilNonCancer)
    17.867 = 17.867
  3. Calculate GW screening level
    GW screening level = min(gwCancer, gwNonCancer)
    1.787 = 1.787
  4. Calculate Soil cancer RBSL
    Soil cancer RBSL = (targetRisk * bodyWeight * params.AT_c) /
    17.867 = 17.867
  5. Calculate Soil non-cancer RBSL
    Soil non-cancer RBSL = (targetHQ * rfdOral * bodyWeight * params.AT_nc) /
    1460 = 1460

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