Pentasodium triphosphate

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study is not conducted to GLP standards. However, the investigations within the study are well documented and scientifically acceptable.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Washing programs in a washing machine were performed with two different types of washing powders: one containing only tripolyphosphates, the other containing as well zeolites. The washings were performed under three different conditions: without load, with a load that was not dirty and with a dirty load.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Pentasodium triphosphate

EC Number:

231-838-7

EC Name:

Pentasodium triphosphate

Cas Number:

7758-29-4

Molecular formula:

H5O10P3.5Na

IUPAC Name:

pentasodium bis(phosphonatooxy)phosphinate

Details on test material:

Phosphate species: orthophosphate, pyrophosphate and tripolyphosphate.

Results and discussion

Any other information on results incl. tables

The studies mainly show that, coming out from the washing machine, 80% of phosphorous is recovered under a soluble form. 60% of the soluble phosphate form is tripolyphosphate (TPP). Thus, 20% of the TPP introduced in the washing machine is transformed or it precipitates during the washing operation. In the more diluted waters coming from the rinsing operation the percentage of soluble phosphorous is notably lower.

The calculation of the speed constant (at room temperature, pH=7 and using concentrations of the phosphate species ranging from 30 to 100 micro mole/l) gave the following values:

- for STPP: K = 2.4 10^-2/day

- for pyrophosphate: K = 3 10^-3/day

This speed constant is 15 times weaker in a solution coming out of a washing machine, in which the concentration of TPP and the pH are higher. This value has to be carefully analysed as the concentration of the phosphate species is dependant on the precipitation of the species that happened during the analysis.