Phosphoric acid, C16-18-alkyl esters, potassium salts

Endpoint summary

Description of key information

Calculation of PNEC soil and sediment according to equilibrium partitioning method.

Additional information

PNEC calculation for sediment and soil based on aquatic toxicity data using the EPM (Equilibrium Partitioning Method)

The PNEC for freshwater sediment, marine sediment and soil was calculated according to the ECHA guidance “Guidance on information requirements and Chemical Safety Assessment, Chapter R.16: Environmental exposure assessment” and “Guidance on information requirements and chemical safety assessment, Chapter R.10: Characterisation of dose [concentration]-response for environment”.

The respective equations for freshwater sediment, marine sediment and soil R.10-2, R.10-3, R.10-5 in the ECHA Guidance R.10 were used:

PNECcomp= Kcomp-water/RHOcomp∙ PNECwater∙ 1000

where

comp = environmental compartment, e. g. freshwater sediment, marine sediment or soil;

PNECcomp= Predicted No Effect Concentration in wet comp, mg/kg of wet comp;

Kcomp-water= comp-water partitioning coefficient, m³/m³;

RHOcomp= bulk density of wet comp, kg/m³, from table R.16-8: Characterisation of environmental compartments)

RHOsoil: 1700 kg/m³,

RHOsediment: 1300kg/m³; and

PNECwater= Predicted No Effect Concentration in water (freshwater or marine), mg/L.

 

The unknown term in the above equation is the partitioning coefficient, Kcomp-water, which is derived from equation R.16-7 in the ECHA guidance Chapter R.16:

Kcomp-water= Faircomp∙ Kair-water+ Fwatercomp+ Fsolidcomp∙ (Kpcomp/1000) ∙ RHOsolid

where

Faircomp= fraction of air in comp, m³/m³ (only relevant for soil); given, from table R.16-8: Characterisation of environmental compartments

Fairsoil= 0.2 m³air/m³soil,

Kair-water= air-water partitioning coefficient; Kair-water = Henry’s Law Constant/(R ∙ T)

T = 285 K

R = gas constant = 8.314 Pa∙m³∙mol-1∙k^-1

Fwatercomp= fraction of water in comp, m³/m³; given, from table R.16-8: Characterisation of environmental compartments

Fwatersed= 0.8 m³water/m³sediment,

Fwatersoil= 0.2 m³-water/m³soil,

Fsolidcomp= fraction of solid in comp, m³/m³; given, from table R.16-8: Characterisation of environmental compartments

Fsolidsed= 0.2 m³soild/m³sediment,

Fsolidsoil= 0.6 m³soild/m³soil,

Kpcomp= solid-water partitioning coefficient in comp, L/kg;

Kpcomp= Foccomp* Koc                  equation R.16-6

where,

Foccomp= weight fraction organic carbon in comp solid, kg oc/kg solid; from table R.16-8: Characterisation of environmental compartments,

Focsed= 0.05 kg oc/kg-solid

Focsoil= 0.02 kg oc/kg-solid

Koc = partitioning coefficient organic carbon-water (794322823 L/kg from substance data set))

RHOsolid= density of the solid phase, kg/m³ (= 2500 given; from table R.16-8: Characterisation of environmental compartments).

Compartment	PNECcomp	Kcomp-water	RHOcomp	PNECwater	Fair-comp	Kair-water	Fwater-comp	Fsolid-comp	Kpcomp	RHOsolid	Foccomp	Koc	HLC	VP	MW	water solubility
Unit	mg/kg of wet comp	m^3/m^3	kg/m^3	mg/L	m^3/m^3		m^3/m^3	m^3/m^3	L/kg	kg/m^3	kg/kg		Pa∙m3/mol	Pa	g/mol	mg/L
freshwater sediment	76,461	993,997	1300	0.1	NA	NA	0.9	0.1	3971641	2500	0.05	79432823	679.15
marine sediment	7,646	99,3997	1300	0.01	NA	NA	0.9	0.1	3971641	2500	0.05	79432823	679.15
soil	140,205	140,205	1700	0.1	0.2	0.287	0.2	0.6	1588656	2500	0.02	79432823	679.15	6.51E-4	648.9	622

PNECfreshwater= 0.1 mg/L

PNECmarine water= 0.01 mg/L

Koc = 79432823 (average Koc of UVCB; calculation according to Koc values of percentage share of individual constituent)

MW = 648.9 g/mol (UVCB, component with highest MW)

water solubility = 622 mg/L

vapour pressure = 6.51*10-4Pa

HLC (Henry’s Law Constant) : (vapour pressure ∙ MW)/ water solubility = 679.15Pa∙m3/mol