Quaternary ammonium compounds, C12-14-alkyltrimethyl, Me sulfates

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From March 18, 1999 to April 30, 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Refer to section 13 for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Test temperature:

room temperature

Analytical monitoring:

yes

Key result

Type:

other: Kadsoc (soil 1)

Value:

18 251 L/kg

Key result

Type:

other: Kadsoc (soil 2)

Value:

16 679 L/kg

Key result

Type:

other: Kadsoc (soil 3)

Value:

812 943 L/kg

Adsorption and desorption constants:

-soil 1: Kfads = 630 ; soil 2: Kfads = 1543; soil 3: Kfads = 2032
-soil 1: Kfdes = 2828 ; soil 2: Kfdes = 6795; soil 3: Kfdes = 2778;
-soil 1: Kadsoc = 18251; soil 2: Kadsoc = 16679; soil 3: Kadsoc = 812943

Kfads / Kfdes: soil 1: 0.22; soil 2: 0.23; soil 3: 0.73

Test concentrations:
- Euro soil 3: 20 mg/L,
- Euro soil 5: 50 mg/L,
- Euro soil 6: 50 mg/L.
Analysis of the active substance by means of spectrophotometry.

Freundlich (Kads(F) isotherm for adsorption:
Euro   log    1/n      r^2 soil  Kads(F)
____________________________
3    2.7991  0.773   0.9898
5    3.1883  0.7226  0.9619
6    3.308   0.7709  0.9592

Freundlich (Kdes(F) isotherm for desorption:
Euro   log    1/n      r^2 soil  Kdes(F)
_____________________________
3    3.4515  0.5353  0.988
5    3.8322  0.5762  0.9928
6    3.4437  0.7291  0.9984

Validity criteria fulfilled:

yes

Conclusions:

Based on the results fo the read-across study, the test substance adsorbed onto soil and did not desorb easily for the three soil types used, therefore it could be classified as immobile.

Executive summary:

A study was conducted to determine the adsorption / desorption potential of the read across substance, C12 -16 ADBAC, according to OECD Guideline 106, in compliance with GLP. The soil adsorption / desorption properties were evaluated using the batch equilibrium method. The test substance adsorbed onto the different soil samples tested (soil 1: Kadsoc = 18,251; soil 2: Kadsoc = 16,679; soil 3: Kadsoc = 812,943) and did not desorb easily. The desoprtion coefficients (Kdoc) were determined to be 81971, 73459 and 1111200 for soils 1, 2 and 3 respectively. The mean Koc was calculated to be 282,624.3 L/kg. The high concentrations of test substance used in the study (0.5 g test substance for 1 g soil) led to a less accurate extrapolation to lower concentrations. Adsorption is likely to be higher at lower concentrations than suggested by the outcome of this study. Based on the results, the read-across substance adsorbed onto soil and did not desorb easily for the three soil types used, therefore it could be classified as immobile (Geffke, 1999).

Key value for chemical safety assessment

Koc at 20 °C:

282 624.3

Additional information

A study was conducted to determine the adsorption / desorption potential of the read across substance, C12 -16 ADBAC, according to OECD Guideline 106, in compliance with GLP. The soil adsorption / desorption properties were evaluated using the batch equilibrium method. The test substance adsorbed onto the different soil samples tested (soil 1: Kadsoc = 18,251; soil 2: Kadsoc = 16,679; soil 3: Kadsoc = 812,943) and did not desorb easily. The desoprtion coefficients (Kdoc) were determined to be 81971, 73459 and 1111200 for soils 1, 2 and 3 respectively. The mean Koc was calculated to be 282,624.3 L/kg. The high concentrations of test substance used in the study (0.5 g test substance for 1 g soil) led to a less accurate extrapolation to lower concentrations. Adsorption is likely to be higher at lower concentrations than suggested by the outcome of this study. Based on the results, the read-across substance adsorbed onto soil and did not desorb easily for the three soil types used, therefore it could be classified as immobile (Geffke, 1999).

Based on the read across substance, C12-16 ADBAC, the mean Koc value of 282,624.3 L/kg from the available study has been used for hazard/risk assessment. Based on the results of the read across studies, the test substance, Quaternary ammonium compounds, C12-14 alkyltrimethyl, Me sulfates, can be considered to be immobile in soil. Therefore, it is not expected to pose an environmental risk for contamination of ground water.

[LogKoc: 5.45]