2-ethoxy-1-methylethyl acetate

Endpoint summary

Additional information

The available aquatic toxicology studies for ethoxypropyl acetate (EPA) are summarized below.  This information is supplemented by toxicology data for a close structural analogue, methoxypropyl acetate (MPA).  Based on the high level of understanding of metabolism of glycol ethers and their acetates, it is reasonable to expect the toxicologic properties of ethoxypropyl acetate to be similar to those demonstrated for its monomethyl analogue. Overall, EPA can be considered as slightly toxic to the aquatic environment.

According to the acute toxicity information, the most sensitive species is invertebrates, showing an EC50 value of 110mg/l. However, the toxicity to fish was quite similar (LC50 of 140mg/l). Information from a QSAR however suggests that fish are more sensitive that daphnia. Chronic data is available for a surrogate substance only. Available information suggests this provides good read across potential to predict toxicity to fish. However, the available experimental data for acute toxicity suggests that EPA is more toxic to this species than MPA. The most sensitive species for MPA is fish (both chronic and acute toxicity.) To derive the PNEC for EPA, the chronic fish toxicity data is used as a starting point. Discussions on the choice of assessment factor are in the overall ecotoxicological summary.

 

A 96-hour aquatic toxicity study (semi-static) of ethoxypropyl acetate in Rainbow Trout produced the following LC values.

3-hour LC50 = 680 mg/L (95% CL 580-800)

6-hour LC50 = 210 mg/L (95% CL 180-250)

24-hour LC50 = 150 mg/L (95% CL 120-180)

48-, 72- and 96-hour LC50 = 140 mg/L (95% CL 120-170)

96-hour LC0 = 100 mg/L

Reactions to exposure were observed at all concentrations tested; therefore a NOEC cannot be established based on the findings of this study.

A 48-hour aquatic toxicity study (static) of ethoxypropyl acetate in Daphnia magna produced the following EC50 and NOEC values.

24-hour EC50 = 220 mg/L (95% confidence limits 180 – 260 mg/L)

48-hour EC50 = 110 mg/L (95% confidence limits 96 – 130 mg/L)

24-hour NOEC = 56 mg/L

48-hour NOEC = 32 mg/L

In a 72-hour aquatic toxicity study (static) in green alga, a limit concentration of 100 mg/L ethoxypropyl acetate did not affect the rate of growth or total biomass.  The EC50 is therefore considered to be > 100 mg/L, and the NOEC is considered to be >= 100 mg/L under the conditions of this test.

In a 16-hour aquatic toxicity study (static) in Pseudomonas putida, the concentration of ethoxypropyl acetate producing 10% growth inhibition (EC10) was calculated to be 560 mg/L.  The highest concentration that did not inhibit growth under these test conditions was 62.5 mg/L.

In a 21-day toxicity study (semi-static) in Daphnia magna, methoxypropyl acetate produced the following results:

21-day LC50 (parental) > 100 mg/L (equimolar equivalent of ethoxypropyl acetate is 110 mg/L

21-day EC50 (reproduction) > 100 mg/L (equimolar equivalent of ethoxypropyl acetate is 110 mg/L

21-day NOEC (reproduction) >= 100 mg/L (equimolar equivalent of ethoxypropyl acetate is 110 mg/L