Bis(2-ethylhexyl) maleate

Endpoint summary

Additional information

For all aquatic endpoints, only data for freshwater species are available. There are no data available for marine species.

For the determination of the acute toxicity of bis(2-ethylhexyl)maleate to fish, three static studies were conducted. One study was conducted according to OECD 203, and two studies were conducted according to the German DIN standard DIN 38 412. The 96 -hour study was selected as the key study, as this test guideline is current standard and internationally accepted. In this test, the LC50 is related to an exposure period of 96-hour, whereas in the tests according to DIN standard, the exposure period was only 48 hours. Furthermore, the test organism used in the OECD test, zebra fish, is more reliable than Golden orfe, used in the tests according to DIN standard. Therefore, the OECD test was selected as the key study, although the LC50 of > 100 mg/L is higher than the LC50 values of the DIN standard tests.

For assessing the acute toxicity to invertebrates, also three studies are available, all conducted with the freshwater invertebrate Daphnia magna. Here, also one study was conducted according to OECD 202, and two studies were conducted according to German DIN standard. In the OECD study, an analytical determination of the test concentration was conducted, resulting in a mean recovery of about 102%. Therefore, the EC50 of 59.5 mg/L is related to nominal values. As this value is the lowest of the three invertebrate studies, it was selected as the key parameter.

One study is available reporting the long-term toxicity of bis(2-ethylhexyl)maleate to Daphnia magna. Here, a 21-day NOEC of 0.1 mg/L was reported based on reproduction rate and related to nominal concentrations.

For algae, one 72-hour study is available conducted according to OECD 201 and using Pseudokirchneriella subcapitata as test organism. In this test, a 72-hour EC50 of >619 µg/L and a 72-hour NOEC of 52 µg/L are reported. Both values are based on mean measured values.

For microorganisms, results from three aerobic and two anaerobic studies are available. The first aerobic study was conducted according to OECD 209, the second one was conducted using a modification of OECD 209, and the third study was conducted according to a German DIN standard. The study conducted according to OECD 209 without modifications was selected as the key study. In this study, all EC values were above the test concentration of 1000 mg/L, which was the only concentration tested. Although the study according to the DIN standard resulted in a lower EC10 value of >300 mg/L. Effects at the highest test concentration of 1000 mg/L could not be determined due to technical reasons. This study was not chosen as the key study, as the exposure period was only 30 minutes, whereas in the OECD study the exposure period was 3 hours. As bis(2-ethylhexyl)maleate is very poorly water soluble, it is assumed that a longer exposure period would rather result in a realistic result.