Petrolatum (petroleum), oxidized, Bu ester

Short-term toxicity to aquatic invertebrates

Description of key information

Daphnia magna: 24 and 48 hour EC₅₀ of > 100 % saturated solution (equivalent to 52 mg/L). 24 and 48 hour NOEC 100 % saturated solution (equivalent to 52 mg/L). The study demonstrated that there were no toxic effects at saturation.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

52 mg/L

Additional information

A study was performed to assess the acute toxicity of the test material to Daphnia magna. The study was performed under GLP conditions and in accordance with the standardised guidelines OECD 202 and EU Method C.2.

During the study two experiments were performed. The first experiment was performed in open glass beakers. At the end of the test the measured DOC concentrations were unexpectedly low (63 - 73 % of the starting concentration). Therefore, a second experiment was performed in closed and open vessels. The measured DOC concentrations in the second experiment were significantly lower than in the first experiment, but the recovery in closed vessels after 48 hours was 88 % of the measured starting concentration.

In both experiments twenty daphnia were exposed to the test material for 48 hours in a static test system. After 24 and 48 hours, the immobilised daphnia were counted.

In experiment 1, none of the daphnia in the control group died or showed any signs if abnormal behaviour throughout the test. In the treatment vessels, one daphnid was found immobile at 24 hours and a further daphnid was found immobile at 48 hours in the 18 % saturated solution. All other daphnia, in all other treatment vessels, appeared normal. In experiment 2 none of the daphnia died or showed any signs of abnormal behaviour throughout the test, either in the control, or treatment vessels.

Potassium dichromate was used as positive control in a separate reference study. The EC50 was determined to be 1.5 mg/L which was well within the required range of 0.6 - 1.7 mg/L.

At the beginning and at the end of the test, the content of test material in the test solutions was determined by calculation from content of organic carbon of the test material (76.47 % based on elemental analysis) and DOC measurement. The correction between nominal and measured concentration was poor. The poor correction was caused by the limited solubility of the test material in the test media. The DOC concentrations in the first experiment were much higher than in the second experiment. Therefore, the determination of the biological results was based on the geometric mean of the measured concentrations in the first experiment.

Under the conditions of the test, the acute toxicity of the test material to the freshwater invertebrate Daphnia magna gave a 24 and 48 hour EC₅₀ of > 100 % saturated solution (equivalent to 52 mg/L). The No Observed Effect Concentration at 24 and 48 hours was determined to be 100 % saturated solution (equivalent to 52 mg/L). The study demonstrated that there were no toxic effects at saturation.

The study was conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study was therefore assigned a reliability score of 1 according to the criteria of Klimisch (1997).