TABLE 3.

VELMA 6PPD/6PPD-Q contaminant parameters and values.

Parameter name	Type	Value	Description
directKocSpecification	Model	True	Set = True when the value of Koc is known for a contaminant (check the EPA CompTox dashboard). When Koc is unknown, set = False and use alternate VELMA parameters and methods described in McKane et al. (2022a) to estimate Koc
Koc	CompTox Parameter (6PPD)	11,000 L/kg	Contaminant soil adsorption coefficient
setMolarSolubilityCoefficient	CompTox Parameter (6PPD)	0.000158 mol/L	Molar solubility coefficient (mol/L)
setMolarMass	CompTox Parameter (6PPD-Q)	268.404 g/mol	Molar mass (g/mol). Value is used to internally convert mol to g
setChemMaxDecay	CompTox Parameter (6PPD)	0.2,207,475	Maximum contaminant decay rate (fraction per day)
logKow	Hu et al., (Seattle, 2022a) Parameter (6PPD-Q)	2.745	Octanol-water partition coefficient (unitless)