Environmental Modeling Community of Practice

EPA On-line Tools for Site Assessment Calculation

When chemicals are released into the environment from a mixture like a petroleum hydrocarbon fuel, the water solubilities of the chemicals are typically far lower than their published solubilities. For example, the solubility of benzene is around 1750 mg/L, but typical maximum benzene concentrations resulting from equilibrium between gasoline and water are only 20 - 40 mg/L. This occurs because the concentration (or effective solubility) depends on the abundance of the chemical in the fuel.

Experimental, temperature-dependent version of the calculator.

The effective solubility calculator only calculates the partitioning between water and a fuel. Use the mass distribution calculator to determine the partitioning (concentrations) between water, air, fuel and solids in the subsurface.

Effective Solubility Calculator

Effective Solubility C_w = x_o S

C_w = Effective solubility
x_o = mole fraction (of chemical in fuel)
S = solubility

Mole Fraction x_o = MF_x MW_o / MW_x

MF_x = mass fraction of selected chemical in fuel
MW_o = average molecular weight of fuel
est. 105 g/mole for gasoline
est. 165 g/mole for Jet fuel
est. 230 g/mole for diesel fuel
MW_X = molecular weight of selected chemical

Site Name

Date

Chemical

Solubility (S)

mg/L

Optional Revised Solubility (S)

mg/L

Example Fuel

Average Molecular Weight of Fuel (MW_o)

Percent Mass Fraction

Effective Solubility (C_w)

mg/L

Fuel composition note: