ETHYL 2-METHYL-4-PENTANOATEETH OXANOATE-369 CRUDE

Biodegradation in water: screening tests

Description of key information

Eth Oxanoate 369 Crude is readily biodegradable based on read-across from its major constituent Ethyl 2-methyl-3-pentenoate, which was tested following OECD TG 301D.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

No data is available for the target substance. Therefore, read-across is performed to the major constituent Ethyl 2-methyl-3-pentenoate (CAS# 58625-89-1). The ready biodegradability study on Ethyl 2-methyl-3-pentenoate is summarised below, which is followed by the read-across justification.

Biodegradation in water: ready biodegradability of Ethyl 2-methyl-3-pentenoate

A biodegradation study was performed on the source substance according to OECD TG 301D (Closed Bottle test) and under GLP conditions. In this study, river water was exposed to 2.0 mg/L of the test substance for 28 days. Inhibition of the endogenous respiration of the inoculum by the test substance at day 7 was not detected. The test is valid as shown by endogenous respiration of 1.00 mg/L and by the total mineralization of the reference compound, sodium acetate. Sodium acetate was degraded by 90% of its theoretical oxygen demand after 14 days. The oxygen concentrations were > 0.5 mg/L in all bottles during the test period. The test substance was biodegraded for 78% at day 28 and the 14-day time window was fulfilled. The test item should therefore be classified as readily biodegradable.

Eth Oxanoate 369 Crude and its ready biodegradability using read across information from Ethyl 2-methyl-3-pentenoate (CAS# 58625-89-1) its main constituent

 

Introduction and hypothesis for the analogue approach

The multi-constituent substance Eth Oxanoate 369 Crude consists of two main constituents: 62% ethyl 2-methyl-3-pentenoate (CAS# 58625-89-1) and 32% ethyl 2‐methylpentanoate (CAS# 39255-32-8). For Eth Oxanoate 369 Crude, no experimental biodegradation data are available. In accordance with Article 13 of REACH, lacking information can be generated by means other than experimental testing, i.e. applying alternative methods such as, QSARs, grouping and read-across. For assessing the ready biodegradability of Eth Oxanoate 369 Crude, the analogue approach is selected because for one of the constituents, ethyl 2-methyl-3-pentenoate, reliable ready biodegradation information is available which can be used for read across.

Hypothesis: Eth Oxanoate 369 Crude has the same ready biodegradability potential as ethyl 2-methyl-3-pentenoate based on similarity in chemical structure and biodegradable fragments.

Available information: For the major constituent (ethyl 2-methyl-3-pentenoate), a ready biodegradation study was performed according to OECD TG 301D (Rel. 1, Closed Bottle Test under GLP). In this study, ethyl 2-methyl-3-pentenoate was biodegraded by 78% at day 28.

Target chemical and source chemical(s)

Chemical structures of the target chemical and the source chemical(s) are shown in the data matrix, including physico-chemical properties.

Purity / Impurities

The major and minor constituents of Eth Oxanoate 369 Crude are presented in the Data matrix. The impurities of Eth Oxanoate 369 Crude are < 10%.

Analogue approach justification

According to Annex XI 1.5, read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection: For Eth Oxanoate 369 Crude, the constituent ethyl 2-methyl-3-pentenoate was selected as source chemical for read-across because it is the major constituent (62%) of Eth Oxanoate 369 Crude and its experimental biodegradation information is available.

Structural similarities and differences: The major constituent, ethyl 2-methyl-3-pentenoate has a molecular weight of 142 g/mol. It has a similar structure to the minor constituent (32%), ethyl 2‐methylpentanoate, which has a molecular weight of 144 g/mol. The only difference in their structures is that ethyl 2-methyl-3-pentenoate has a double bond on the carbon 3 of the pentene ester.

Bioavailability: The bioavailability of ethyl 2-methyl-3-pentenoate and ethyl 2‐methylpentanoate is very similar based on similarities in log Kows: 3.1 measured and 2.76 calculated, respectively.

Biodegradability fragments: Ethyl 2-methyl-3-pentenoate has a similar probability of biodegradation to ethyl 2‐methylpentanoate as predicted by BIOWIN 5 and 6. Ethyl 2-methyl-3-pentenoate has biodegradation probabilities of ca. 0.63 and 0.78, respectively, while ethyl 2‐methylpentanoate has values of ca. 0.69 and 0.86, respectively and are even slightly higher. Both types exceed the 0.5 probability and present therefore ready biodegradability.

Uncertainty of the prediction: There are no uncertainties other than those addressed above. The minor constituent ethyl 2‐methylpentanoate is readily biodegradable (ECHA dissemination site: https://echa.europa.eu/nl/registration-dossier/-/registered-dossier/10528), further supporting the read across.

Data matrix

The relevant information on physico-chemical properties and environmental fate characteristics are presented in the data matrix below.

Conclusions on biodegradation for hazard and risk assessment

For Eth Oxanoate 369 Crude, no experimental biodegradation information is available. Read-across from Ethyl 2-methyl-3-pentenoate is used to fill this data gap. When using read-across, the result derived should be applicable for C&L and/or risk assessment, and be presented with adequate and reliable documentation. This documentation is presented in the current text. Ethyl 2-methyl-3-pentenoate is readily biodegradable (78% degradation after 28 days in an OECD TG 301D test, Rel. 1). Based on structural similarity, physico-chemical parameters and biodegradable fragments between the major and minor constituents the information from the major constituent can be used to predict the ready biodegradability for the whole substance.

Final conclusion: Eth Oxanoate 369 Crude is readily biodegradable.

Data matrix to support the read across to Eth Oxanoate 369 Crude from Ethyl 2-methyl-3-pentenoate on biodegradability.

 

Endpoint	Eth Oxanoate 369 Crude	Ethyl 2-methyl-3-pentenoate	Ethyl 2‐methylpentanoate
	Target	Major constituent Source	Minor constituent
Chemical structure
CAS number	Not applicable	58625-89-1	39255-32-8
EC number	952-991-2	854-058-4	254-384-1
Typical conc. (%)	Not applicable	62	32
REACH registered	-	registered	registered
Empirical formula	Not applicable	C8H14O2	C8H16O2
Molecular weight	142 – 144	142	144
Phys-chem
Log Kow	3.0 (measured, major constituent)*	2.54 (EPISUITE) 3.1 (measured)*	2.76 (EPISUITE) 2.09 (HPLC, ECHA disseminated dossier)
Water Solubility (mg/L)	612.3 (measured, major constituent)	612.3 (measured)	467 (ECHA dissemination site)
Environmental fate
Ready biodegradability	Read across  from major constituent)	Readily biodegradable (OECD TG 301D) (BIOWIN 5 and 6, 0.63 and 0.78, respectively (probability > 0.5))	Read across from ethyl methyl butyrate (ECHA dissemination site) (BIOWIN 5 and 6, 0.69 and 0.86, respectively (probability > 0.5))

*Same substance is measured with a log Kow difference of 0.1

 

Annex 1

BIOWIN results of ethyl 2-methyl-3-pentenoate: see attached documentation

BIOWIN results of ethyl 2‐methylpentanoate: see attached documentation

BIOWIN results of Ethyl 2‐methyl-4-pentenoate: see attached documentation