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A 96 hour acute semi-static toxicity study in zebra fish (Brachydanio rerio) was performed to assess the toxicity of dimethylol propionic acid (Bis-MPA). The study was performed to GLP and according to OECD 203 Test Guideline. No mortalities were observed during the test and the LC50 value over the 96 hour test period was observed to be >1000 mg/L (based on nominal exposure concentrations) (Olsson, 1993).

The 48 hour acute toxicity of Bis-MPA to Daphnia magna was carried out in a static system according to OECD 202 and EU guidelines. Four replicate vessels, each containing 5 daphnids were exposed to nominal concentrations of 0 (control), 12.5, 25, 50 and 100 mg/L over a 48 hour exposure period. The measured pH in the freshly prepared 50 and 100 mg/L test media were 7.3 and 5.8, therefore additional test vessels were prepared where the pH was neutralised. Measured concentrations demonstrated that test media were adequately prepared and maintained during the exposure period, the results of the study were therefore based on nominal exposure concentrations. pH had no effect on Daphnia mobility during the study. The 48-hour EC50 was determined to be >100 mg/L (the highest nominal concentration tested) (Jatzek, 1999).

 

A 72 hour algal growth inhibition study, test species, Selenastrum capricornutum, was performed to determine the toxic effects of the test substance Bis-MPA. The test was conducted according to OECD test guideline 201, and performed to GLP. The 72 hour EC50 value, based on growth rate, was calculated as 750 mg/L (based on nominal exposure concentrations) (Olsson, 1993).

 

Activated sludge obtained from laboratory wastewater plants treating municipal sewage was exposed in a 30-minute inhibition of oxygen consumption test to 1000 mg Bis-MPA/L. The test design followed OECD 209 guidelines. The 30-minute EC50 based on respiration inhibition was >1000 mg/L (the highest nominal exposure concentration tested) (Reuschenbach, 1999).

In the chemical safety assessment performed according to Article 14(3) in connection with Annex I section 3 (Environmental Hazard Assessment) no hazard was identified. Therefore according to REACH Annex I (5.0) exposure estimation is not necessary for long-term toxicity to fish and aquatic invertebrates. Consequently, in accordance with Column 2 of REACH Annex IX, the studies do not need to be conducted as all identified uses of the substance are assessed as safe for the environment.