Tetrakis(hydroxymethyl)phosphonium chloride

Adsorption / desorption

Description of key information

The mean value of the adsorption coefficients of THPS based on organic carbon is 153 L/kg. Therefore THPS has a medium to high 
mobility in various soil and sediment matrices.
By analogy with THPS, THPC is expected to have a medium to high mobility in soil and sediments.
The calculation method (KOCWIN model) performed with THPC showed a Koc of 10 L/kg, which confirms a high mobility in soils.

Key value for chemical safety assessment

Koc at 20 °C:

153

Additional information

Because of the salt nature of THPC, hazard properties of chloride salt could be predicted to be equivalent to hazard properties of the sulphate salt (THPS). The read across with a similar substance as THPS is then considered as relevant.

A soil/sediment adsorption/desorption study is available for THPS.

The study is of reliability (1) and has been defined as key study.

Results are summarised in table below:

Adsorption onto / desorption from soils

 

Guideline / Test method	Adsorbed a.s. [%]	Ka^1	KaOC^2	Kd^3	KdOC^4	Ka/ Kd^5	Degradation products
							Name	[%] of a.s.
Agricultural sand	17.5	0.4	210	1.7	960	0.24	THPO BMPA Unknown	39.5 N.O. N.O.
Silt loam	34.6	1.4	126	1.6	149	0.88	THPO BMPA Unknown	66.8 N.O. N.O.
Pond sediment	35.9	0.7	72	1.5	159	0.47	THPO BMPA Unknown	39.1 N.O. 42.5
Sandy loam 1	29.3	1.0	146	1.7	240	0.59	THPO BMPA Unknown	30.2 N.O. N.O.
Sandy loam 2	45.1	1.9	266	1.6	223	1.19	THPO BMPA Unknown	58.3 N.O. N.O.
Sandy loam 3	27.1	0.6	81	1.5	210	0.40	THPO BMPA Unknown	N.O. N.O. N.O.
Marine sediment	17.2	0.4	167	1.7	735	0.24	THPO BMPA Unknown	17.7 N.O. N.O.

¹K_a= Adsorption coefficient
²K_aOC= Adsorption coefficient based on organic carbon content
³K_d= Desorption coefficient
⁴K_dOC= Desorption coefficient based on organic carbon content
⁵K_a/ K_d= Adsorption / Desorption distribution coefficient

Sandyloam 1: first test

Sandyloam 2: repeat test, non-autoclaved

Sandyloam 3: repeat test, autoclaved

N.O.: not observed