Octadecyl 3-mercaptopropionate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

This selected scenario covers the category approach for which the read-across hypothesis is based on structural similarity. For the REACH information requirement under consideration, the property investigated in studies conducted with different source substances is used to predict the property that would be observed in a study with the target substance if it were to be conducted. Similar properties are observed for the different source substances; this may include absence of effects for every member of the category.
There are expected to be differences in strength of the effects forming a regular pattern. The prediction will be based on a worst-case approach or trend analysis as appropriate for the respective endpoint. The read-across is a category approach based on the hypothesis that the substances in this category share structural similarities with common functional groups. This approach serves to use existing data on aquatic toxicity for substances in this category.
The hypothesis corresponds to Scenario 4 of the RAAF. The substances MMP, BuMP, EHMP, iOMP, iC13MP, ODMP, GDMP, TMPMP, PETMP, and Di-PETMP are esters of a common acid, 3-mercaptopropionic acid (3-MPA). The key functionality and main driver for ecotoxicity of the substances within this category is the presence of free SH-groups. It can be predicted with high confidence that the substances within this category will lead to the same type of effects.
For details, please refer to the category document attached to Iuclid section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Oxygen conditions:

aerobic

Remarks on result:

other: inherently biogradable based on read-across

Interpretation of results:

inherently biodegradable

Conclusions:

Overall, esters with short carbon chains are readily biodegradable. With increasing carbon chain length, biodegradation rates decrease. Esters of branched, higher or multifunctional alcohols are not readily biodegradable but nevertheless undergo considerable biodegradation and can be considered to be inherently biodegradable. Based on the available data, ODMP is predicted to be inherently biodegradable.

Description of key information

Overall, esters with short carbon chains are readily biodegradable. With increasing carbon chain length, biodegradation rates decrease. Esters of branched, higher or multifunctional alcohols are not readily biodegradable but nevertheless undergo considerable biodegradation and can be considered to be inherently biodegradable. Based on the available data, ODMP is predicted to be inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater

Additional information

Biodegradation data are available for all substances within the category, with the exception of ODMP.

3-MPA was readily biodegradable in a DOC die away study (OECD TG 301 A) and fulfilled the 10 day window criterion. MMP and BuMP were readily biodegradable in a closed bottle test (OECD TG 301 D). EHMP was readily biodegradable in a CO2 evolution test (OECD TG 301 B). The other tested substances were biodegradable to some degree, but not readily. The mono-alcohol bases esters may be considered to be inherently biodegradable, whereas lower biodegradation rates were observed especially for TMPMP, and DiPETMP.

Substance	Results
MPA	93% biodegradation after 10 d, readily biodegradable
MMP	63.4% biodegradation after 28 d, 10 day window passed, readily biodegradable
BUMP	62.6% biodegradation after 28 d, 10 day window passed, readily biodegradable
EHMP	70% biodegradation after 28 d, 10-day window failed, considered readily biodegradable
IOMP	55% biodegradation after 28 d, inherently biodegradable
iC13MP	35% biodegradation after 28 d, inherently biodegradable
ODMP	No data; prediction: inherently biodegradable
GDMP	72.1% degradation after 28 d, 10-day window failed, considered readily biodegradable
TMPMP	9.1% biodegradation after 28 d, not biodegradable
PETMP	50% biodegradation after 28 d, inherently biodegradable
Di-PETMP	22.4% biodegradation after 28 d, inherently biodegradable

 

Overall, esters with short carbon chains are readily biodegradable. With increasing carbon chain length, biodegradation rates decrease. Esters of branched, higher or multifunctional alcohols are not readily biodegradable but nevertheless undergo considerable biodegradation and can be considered to be inherently biodegradable. Based on the available data, ODMP is predicted to be inherently biodegradable.