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

Toxicity to aquatic algae and cyanobacteria

Description of key information

The 72-h ErC50 of 3.61 mg/L and ErC10 of 1.26 mg/L for green algae were derived by calculating the weighted average of the effect levels of two constituents. The effect levels of the two constituents were predicted via ECOSAR using the log Kows of 3.1 and 2.76 for Ethyl 2-methyl-3-pentenoate and Ethyl 2‐methylpentanoate, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:

5.06 mg/L

EC10 or NOEC for freshwater algae:

1.66

Additional information

The substance is a multi-constituent consisting of 62% Ethyl 2-methyl-3-pentenoate and 32% Ethyl 2‐methylpentanoate. The acute and chronic toxicities of the substance to algae were derived by using the log Kow of the minor constituent which is slightly higher than of the main constituent and therefore presents conservative EC50/EC10 values. 

ECOSAR results of Ethyl 2-methyl-3-pentenoate - Acute algae

The acute algae ErC50 for the ester Ethyl 2-methyl-3-pentenoate is predicted to be 2.86 mg/L based on the ECOSAR V1.11 for esters using a measured log Kow of 3.1, molecular weight of 142 and the equation: Log 96-h EC50 (mmol/L) = -0.6993 (log Kow) + 0.4715. The 96-h EC50 is considered equivalent to the 72h current exposure time in the OECD TG 201 test. The chronic algae EC10 for the ester Ethyl 2-methyl-3-pentenoate is predicted to be 1.05 mg/L based on the ECOSAR SAR for esters using a measured log Kow of 3.1, molecular weight of 142 and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The ChV is considered equivalent to the EC10 in the OECDTG 201 test.

The measured and predicted log Kows of the substance are 3.1 and 2.54. In view of the difference being > 0.5, the measured log Kow of 3.1 is used presenting a conservative value (a lower EC50).

Ethyl 2-methyl-3-pentenoate is in the applicability domain of the ECOSAR prediction because: a) The substance is an ester presenting the toxicity solely by its bioavailability; b) its measured log Kow is 3.1 (≤ 6.4 for acute toxicity and ≤ 8 for chronic toxicity); c) its MW is 1442 (< 1000); and d) the toxicity predicted is below its water solubility of 613 mg/L.

In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on esters. The adequate and reliable documentation, presented, further supports this prediction.

ECOSAR results of Ethyl 2‐methylpentanoate - acute algae

The substance is a multi-constituent consisting of 62% Ethyl 2-methyl-3-pentenoate and 32% Ethyl 2‐methylpentanoate. The acute and chronic toxicities of the substance to algae were derived by using the calculated log Kow of the minor constituent which is slightly higher than of the calculated log Kow of the main constituent and therefore presents conservative EC50/EC10 values. 

The acute algae ErC50 for the ester Ethyl 2‐methylpentanoate is predicted to be 5.06 mg/L based on the ECOSAR V1.11 for esters using an estimated log Kow of 2.76, molecular weight of 144.22 and the equation: Log 96-h EC50 (mmol/L) = -0.6993 (log Kow) + 0.4715. The 96-h EC50 is considered equivalent to the 72h current exposure time in the OECD TG 201 test.

Ethyl 2‐methylpentanoate is in the applicability domain of the ECOSAR prediction because: a) The substance is an ester presenting the toxicity solely by its bioavailability; b) its calculated log Kow is 2.76 (≤ 6.4 for acute toxicity and ≤ 8 for chronic toxicity); c) its MW is 144.22 (< 1000); and d) the toxicity predicted is below its calculated water solubility of 356.67 mg/L. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on esters. The adequate and reliable documentation, presented, further supports this prediction.

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the substance’s prediction. This shows that the prediction is reliable and a Klimisch 2 can be assigned. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on esters (see attached report). The adequate and reliable documentation presented, further supports this prediction.

Chronic algae - Ethyl 2-methyl-3-pentenoate

The algae EC10 for the ester Ethyl 2-methyl-3-pentenoate is predicted to be 1.05 mg/l based on the ECOSAR SAR for esters using a measured log Kow of 3.1, molecular weight of 142 and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The ChV is considered equivalent to the EC10 in the OECDTG 201 test.

Ethyl 2-methyl-3-pentenoate is in the applicability domain of the ECOSAR prediction because: a) The substance is an ester presenting the toxicity solely by its bioavailability; b) its measured log Kow is 3.1 (=< 6.4); c) its MW is 142 (< 1000); and; d) the toxicity predicted is below its water solubility of 613 mg/l.

The measured and predicted log Kows of the substance are 3.1 and 2.54. In view of the difference being > 0.5, the measured log Kow of 3.1 is used presenting a conservative value (a lower EC50).

In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on esters (see attached reports). The adequate and reliable documentation, presented, further supports this prediction.

The algae EC10 for the ester Ethyl 2‐methylpentanoate is predicted to be 1.66 mg/l based on the ECOSAR V1.11 for esters using an estimated log Kow of 2.76, molecular weight of 144.22 and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The ChV is considered equivalent to the EC10 in the OECDTG 201 test.

Ethyl 2‐methylpentanoate is in the applicability domain of the ECOSAR prediction because: a) The substance is an ester presenting the toxicity solely by its bioavailability; b) its estimated log Kow is 2.76 (≤ 6.4); c) its MW is 144.22 (< 1000); and d) the toxicity predicted is below its water solubility of 356.67 mg/L.

There is no measured log Kow available. The predicted log Kow of the substance is 2.76 and is used in the model for presenting the EC10.

In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on esters (see attached reports). The adequate and reliable documentation, presented, further supports this prediction.

Chronic algae - Ethyl 2‐methylpentanoate

The algae EC10 for the ester Ethyl 2‐methylpentanoate is predicted to be 1.66 mg/l based on the ECOSAR for esters using an calculated log Kow of 2.76, molecular weight of 144.22 g/mol and the equation: Log 96h ChV (mmol/L) = -0.5583 (log Kow) - 0.4017. The ChV is considered equivalent to the EC10 in the OECD TG 201 test.

Ethyl 2‐methylpentanoate is in the applicability domain of the ECOSAR prediction because: a) The substance is an ester presenting the toxicity solely by its bioavailability; b) its calculated log Kow is 2.76 (≤ 6.4); c) its MW is 144.22 g/mol (≤ 1000 g/mol); and d) the toxicity predicted is below its calculated water solubility of 356.67 mg/L. The calculated log Kow of the substance is 2.76 and is used in the model for presenting the EC10. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for chronic algae toxicity on esters (see attached reports). The adequate and reliable documentation, presented, further supports this prediction.

The fit in the applicability domain and the availability of an analogue in the training set results in limited uncertainty of the substance’s prediction. This shows that the prediction is reliable and a Klimisch 2 can be assigned. In accordance with REACH Annex XI, the validity of the (Q)SAR is documented in a QMR for acute algae toxicity on esters (see attached report). The adequate and reliable documentation presented, further supports this prediction.