Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

December 5, 1994 - May 19, 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Test temperature:

Room temperature

Analytical monitoring:

yes

Type:

Koc

Value:

>= 780 - <= 16 000

% Org. carbon:

>= 1.3 - <= 9.3

Type:

log Koc

Value:

>= 2.89 - <= 4.2

% Org. carbon:

>= 1.3 - <= 9.3

Mass balances ranged from 85.4-100% AR. The kinetics experiment indicated that adsorption equilibrium was reached after 6 hours. Analysis of the supernatants of the Borstel soil and control samples (no soil) indicated significant degradation during the experiments: the activity in the supernatant consisted of 48-48% and 66-73% bis-(2,2,6,6-tetramethyl-4-[2,4,6-14C]piperidyl) sebacate, respectively. Calculated adsorption parameters (Koc, L/kg) were taken from the report: 1200-2500 (Borstel soil), 1000-2200 (Compost), 16000 (Eurosoil 1), 2200 (Eurosoil 2), 960-2800 (Eurosoil 3), 4400-13000 (Eurosoil 4) and 780 (Eurosoil 5). Koc values are calculated based on total radioactivity in the supernatant. TLC analysis indicated significant degradation, hence bis-(2,2,6,6-tetramethyl-4-[2,4,6-14C]piperidyl) sebacate concentrations in supernatants are actually lower. As a consequence, actual Koc valuescan be expected to be higher and the reported Koc values can be considered worst case with respect to leaching. Desorption (first/second) was 10/6% (Borstel soil), 5.5/2% (Compost), 2.1% (Eurosoil 1), 4.1% (Eurosoil 2), 10/7% (Eurosoil 3), 5.6/1% (Eurosoil 4) and 2.6% (Eurosoil 5) of the radioactivity.

Conclusions:

Koc (L/kg) values for adsorption were 1200-2500 (Borstel soil), 1000-2200 (Compost), 16000 (Eurosoil 1), 2200 (Eurosoil 2), 960-2800 (Eurosoil 3), 4400-13000 (Eurosoil 4) and 780 (Eurosoil 5). Because significant degradation of bis-(2,2,6,6-tetramethyl-4-piperidyl) sebacate took place, actual Koc values can be expected to be higher and the reported Koc values can be considered worst case with respect to leaching.

Description of key information

Adsorption to solid soil phase is expected.

Key value for chemical safety assessment

Koc at 20 °C:

4.2

Additional information

The log Koc was determined to be 4.20 (CIBA-GEIGY 1995). A log Koc of that value indicates that the tested substance binds to soils and sediments.