Fatty acids, C14-18 and C18-unsatd., branched and linear, 2-ethylhexyl esters

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Read-across Category

Key result

Parameter:

% degradation (CO2 evolution)

Value:

>= 76

Sampling time:

28 d

Table1 : Results from key studies on source chemicals for biodegradation in water : screening tests

Identity	CAS	Biodegradation in water: screening tests
Fatty acids, C8-16, 2- ethylhexylesters	135800-37-2	Experimental result: 301D, 97% in 30 d, readily biodegradable
Fatty acids, coco, 2-ethylhexyl esters	92044-87-6	Experimental result: 301D, 90% in 28 d, readily biodegradable
2-Ethylhexyl palmitate	29806-73-3	80.8% degradation(CO2 evolution, 28.0 day) readily biodegradable
Fatty acids, C16-18 and C18-unsatd., 2- ethylhexylesters	85049-37-2	Experimental result: 301B, 76-81%, readily biodegradable
Fatty acids, C16-18, 2-ethylhexyl esters	91031-48-0	No data
2-Ethylhexyl oleate	26399-02-0	Experimental result:301B, 86.8% ,28 days, readily biodegradable
2-Ethylhexyl stearate	22047-49-0	No data

 

Similar biodegradation profile

Several experimental studies showed that members of the category are readily biodegradable according to OECD 301 guidelines based on respirometric measurements (Oxygen consumption or CO2 emission). Since these ready biodegradation tests are performed in very stringent conditions, it can be  anticipated that these substances will disappear very quickly in the environment. Similar structure of the members of the category, and suitable enzymatic processes present in the inoculum explain the ready degradation of the tested substances.

Target substance conclusion

Biodegradation was assessed for most of the members of the category according to 301B and 301D standard guidelines. Based on the results obtained on the category members, the biodegradation of the target substance "Isostearate 2 -ethyl hexyl" was considered to be ≥ 76% within 28 days and this substance is readily biodegradable.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Based on the results available through the category approach and according to the CLP criteria, the registered substance “Isostearate, 2-ethylhexyl” was considered as readily biodegradable with a level of biodegradation ≥ 76% within 28 days in OECD 301B test.

Executive summary:

According to the Regulation (EC) NO. 1907/2006, Annex XI, 1.5, A Read-Across Category for "Long Chain Fatty Acid, 2-ethylhexyl esters" was performed in order to provide informations on Isostearate 2-Ethylhexyl .

This category was based on common and shared properties as:

-   common functional group,

-   common precursors and the likelihood of common impurities resulting from common process of manufacturing,

-   chemically structurally similar breakdown products obtained via the same biological processes into the organisms, and

-   constant pattern in the changing of the potency of the properties across the category.

 

Several experimental studies showed that members of the category are readily biodegradable according to OECD 301 guidelines based on respirometric measurements (Oxygen consumption or CO2 emission).  Similar structure of the members and suitable enzymatic processes present in the inoculum explain the ready degradation of the tested substances.

Based on the results available through the category approach and according to the CLP criteria, the registered substance “Isostearate, 2-ethylhexyl” was considered as readily biodegradable with a level of biodegradation ≥ 76% within 28 days in OECD 301B test.

Description of key information

Based on the results available through the category approach and according to the CLP criteria, the registered substance “Isostearate, 2-ethylhexyl” was considered as readily biodegradable with a level of biodegradation ≥ 76% within 28 days in OECD 301B test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Justification and rationale of the category approach for the isostearate 2-ethyl hexyl :

This category group covers 2-ethyl hexyl esters linked with fatty acid chains (C8 to C18) unsatured and satured. This category includes monoconstituent substances and UVCB substances varying fatty acid chain length. This category was made in order to provide sufficient information for physicochemical, ecotoxicological and toxicological caracterisation of the Fatty acids, C14-18 and C18-unsatd., branched and linear, 2-ethylhexyl esters (CAS No 85186-76-1)

The category group includes:

- Fatty acids, C8-16, 2-ethylhexyl esters (CAS No 135800-37-2)

- Fatty acids, coco, 2-ethylhexyl esters (CAS No 92044-87-6)

- 2-Ethyl hexyl palmitate (29806-73-3)

- Fatty acids, C16-18 and C18-unsatd., 2-ethylhexyl esters (CAS No 85049-37-2)

- Fatty acids, C16-18, 2-ethylhexyl esters (CAS No 91031-48-0)

- 2-Ethylhexyl oleate (CAS No 26399-02-0)

- 2-Ethyl hexyl stearate (CAS No 22047-49-0)

Target substance for Category Approach : Fatty acids, C14-18 and C18-unsatd., branched and linear, 2-ethylhexyl esters (CAS No 85186-76-1)

In accordance with article 13 (1) of Regulation (EC) No. 1907.2006, “information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met. In particular for human toxicity, environmental fate and ecotoxicity, information shall be generated whenever possible by means other than vertebrate animal tests which includes the use of information from structurally related substances (grouping or read across)”. Therefore, the available experimental data were collected and evaluated according to Annex XI requirements.

Summary of available studies on source chemicals for ready biodegradation

Fatty acids, C8 -16, 2 -ethylhexyl esters CAS 135800-37-2

In the key study, the ready biodegradability of Fatty acids, C8-16, 2-ethylhexyl esters was tested in an O2-consumption test according to OECD 301D (Closed bottle test) under GLP conditions (Richterich 2002). The biodegradation of 2 and 5 mg/L test material was monitored for 30 days, giving 97 and > 65% of biodegradation, respectively.  The tested substance is considered as readily biodegradable.

This result is supported by the fact that high biodegradation rates were observed in a marine BODIS test. Only microorganisms present in the natural seawater samples were used as inoculum. After 28 days 96 % of the test material was degraded in the marine test (Molversmyr 1991).

Furthermore, the substance was also shown to be degraded under anaerobic conditions according to ECETOC method (TR No. 28). 77% degradation was determined after a 70 days incubation period (Richterich 1994).

Fatty acids, coco, 2 -ethylhexyl esters CAS 92044 -87 -6

Two ready biodegradation studies are available for Fatty acids, coco, 2-ethylhexyl esters.

The key study was performed according to OECD guideline 301 B and GLP (King, 1994). Secondary effluent from an unacclimatised activated sludge plant was used as inoculum. During the 28-day test period, biodegradation reached 90%, based on CO2 evolution, and the 10-day window was met. The tested substance is considered as readily biodegradable.

The supporting study with Fatty acids, coco, 2-ethylhexyl esters was also performed according to OECD guideline 301 B and GLP, using activated sludge as inoculum (Van der Kerken, 1995). During the 28-day test period, biodegradation in the two replicates reached 69% and 68% respectively, based on CO2 evolution. Since the substance is a UVCB and thus consists of components with different chain lengths, sequential (instead of concurrent) biodegradation can take place. Referring to Annex I to the OECD Guideline for Testing of Chemicals “Revised introduction to the OECD guidelines for testing of chemicals, section 3” (OECD, March 2006), the 10-day window should not be considered for this UVCB substance. Since the biodegradation is  ≥  60% within 28 days, the tested substance can be regarded as readily biodegradable.

2 -Ethylhexyl palmitate CAS 29806 -73 -3

One key study is available for the  2-ethylhexyl palmitate. This ready biodegradion study was carried out following a procedure similar to OECD Guideline 310 and according to GLP (King, 1993). Secondary effluent from an activated sludge plant was used as inoculum. During the 28-day test period, biodegradation reached 80.8%, based on CO2 evolution, and the 10-day window criterion was met. The substance  2-ethylhexyl palmitate is considered as readily biodegradable.

Fatty acids, C16-18 and C18-unsatd., 2-ethylhexyl esters CAS 85049-37-2

The ready biodegradability of Fatty acids, C16-18 and C18-unsatd., 2-ethylhexyl esters was tested in a CO2-evolution test according to OECD 301B and to GLP (Van der Kerken 1995). The biodegradation of 10 mg/L DOC of the test substance was monitored for 28 days. After 28 days, 76 to 81% of the initial test substance was degraded. As the pass level of 60% was reached in a time period of 10 days, the tested  substance is considered as readily biodegradable.

2 -Ethylhexyl oleate CAS 26399-02-0

The ready biodegradability of 2-ethylhexyl oleate (CAS 26399 -02 -0) was tested in a CO2 -evolution test according to OECD 301B and to GLP (King 1994). The biodegradation of 10.3 mg/L organic carbon of the tested substance was monitored for 28 days. After 28 days, 86.8% of the initial test substance was degraded. Based on these findings, the substance 2-ethylhexyl oleate is considered to be readily biodegradable.

Conclusion on the target chemical

According to the Regulation (EC) NO. 1907/2006, Annex XI, 1.5, A Read-Across Category for "Long Chain Fatty Acid, 2-ethylhexyl esters" was performed in order to provide informations on Isostearate 2-Ethylhexyl .

This category was based on common and shared properties as:

-   common functional group,

-   common precursors and the likelihood of common impurities resulting from common process of manufacturing,

-   chemically structurally similar breakdown products obtained via the same biological processes into the organisms, and

-   constant pattern in the changing of the potency of the properties across the category.

 

Several experimental studies showed that members of the category are readily biodegradable according to OECD 301 guidelines based on respirometric measurements (Oxygen consumption or CO2 emission).  The similar structure of the members of the category and the suitable enzymatic processes present in the inoculum explain the ready degradation of all the tested substances.

Based on the results available through the category approach and according to the CLP criteria, the registered substance “Isostearate, 2-ethylhexyl” was considered as readily biodegradable with a level of biodegradation ≥ 76% within 28 days in OECD 301B test.