Phosphorodithioic acid, O,O-di-dodecyl-esters, zinc salts, neutral and basic

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 Jun - 22 Sep 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Version / remarks:

adopted in 1995

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

adopted in 2008

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Integration und Soziales des Landes Nordrhein-Westfalen, Düsseldorf, Germany

Type of method:

flask method

Specific details on test material used for the study:

Storage conditions: at room temperature; tightly closed; dry

Water solubility:

ca. 0.16 g/L

Conc. based on:

element

Remarks:

based on phosphorus analysis

Temp.:

23 °C

pH:

ca. 5.75

Water solubility:

ca. 0.14 g/L

Conc. based on:

element

Remarks:

based on sulphur analysis

Temp.:

23 °C

pH:

ca. 5.75

Water solubility:

ca. 0.072 g/L

Conc. based on:

element

Remarks:

based on zinc analysis

Temp.:

23 °C

pH:

ca. 5.75

Results
Table 1 – P analysis results

Test item amount [g]	Added water volume [mL]	Shaking time at 30 °C [h]	Dilution factor	Analysed concentration of P [mg/L]	Mean value P [g/L]	pH value*
0.5193	50	72	10	0.941953	0.0097	5.7
0.5052				0.999222
0.5134		96		1.04534	0.0106	5.8
0.5163				1.06825
0.5078		120		1.00299	0.0103	5.7
0.5085				1.06618

*the purified water used for the tests had a pH of 5.5

Table 2 – S analysis results

Test item amount [g]	Added water volume [mL]	Shaking time at 30 °C [h]	Dilution factor	Analysed concentration of S [mg/L]	Mean value S [g/L]	pH value*
0.5193	50	72	10	1.64325	0.0171	5.7
0.5052				1.77907
0.5134		96		1.81947	0.0184	5.8
0.5163				1.86057
0.5078		120		1.73066	0.0179	5.7
0.5085				1.84641

*the purified water used for the tests had a pH of 5.5

Table 3 – Zn analysis results

Test item amount [g]	Added water volume [mL]	Shaking time at 30 °C [h]	Dilution factor	Analysed concentration of Zn [mg/L]	Mean value Zn [g/L]	pH value*
0.5193	50	72	10	0.478315	0.0048***	5.7
0.5052				(0.318900)**
0.5134		96		0.442524	0.0047	5.8
0.5163				0.495109
0.5078		120		0.475980	0.0048	5.7
0.5085				0.489457

*the purified water used for the tests had a pH of 5.5
**outlier, not used for test evaluation
***calculated from single measurement

The mean value of the samples after 120 h did not exceed the mean values of the samples (P, S and Zn) after 96 h and 72 h by more than 15%. So, 3 duplicate sets of samples showed no tendency of increasing concentration values.

Table 4 – Results summary (23 °C, pH 5.7 – 5.8)

Water solubility mean value [g/L]	Standard deviation [g/L]	Rel. standard deviation [%]	Water solubility mean value test item [g/L]
P samples 1 -6: 1.0E-02	4.9E-04	4.8	0.16*
S samples 1 -6: 1.8E-02	8.2E-04	4.6	0.14**
Zn samples 1; 3 – 6: 4.8E-03	2.0E-04	4.3	7.2E-02***

*Calculated with the content of the neat test item given by the study monitor: 6.19%
** Calculated with the content of the neat test item given by the study monitor: 12.90%
*** Calculated with the content of the neat test item given by the study monitor: 6.69%

The relative standard deviations did not exceed 15%, therefore the tests were valid.

Description of key information

0.16 g/L at 23°C and pH 5.75, based on phosphorus

0.14 g/L at 23 °C and pH 5.75, based on sulphur

0.072 g/L at 23 °C and pH 5.75 based on zinc (OECD 105, Flask method with modified procedure)

Key value for chemical safety assessment

Water solubility:

150 mg/L

at the temperature of:

23 °C

Additional information

The key value of water solubility used for the PNEC and DNEL calculation, as well as in the exposure assessment is the mean value (150 mg/L) of solubility measured based on phosphorus and sulphur, because it is the worst case.