Diethyl carbonate

Endpoint summary

Additional information

For the toxicity of diethyl carbonate (DEC) to aquatic organisms, several study results are reported on most relevant trophic levels, both for the substance itself as well as on structurally related carbonate esters exhibiting the same mode of action. Whereas, not all of the results cited here can be assigned fully assignable with respect to their reliability, taken together, the available data clearly document the low toxicity of DEC on different aquatic species.

According to REACH Regulation (Annex VIII, 9.1.3, column 2), the study on the acute toxicity of fish does not need to be done if there are mitigating factors indicating that aquatic toxicity is unlikely to occur. In reliable experimental toxicity studies on toxic effects of diethyl carbonate or related carbonate esters, respectively, to aquatic invertebrates (48 h EC50 >100 mg/L) and algae (72 h EC50 >100 mg/L based on nominal concentrations each) EC50 values could not be retrieved up to the highest test concentration applied.

Further experimental test results were reported for the acute toxicity of the structurally related carbonate ester dimethyl carbonate on Leuciscus idus: NOEC=1000 mg/L (study conducted acc. to OECD guideline 203; reliability not assignable).

The calculation of the acute toxicity of diethyl carbonate to fresh and marine water fish via ECOSAR v1.00 yielded 96 h LC50 values ranging from 45.1 to 419.4 mg/L. For adverse effects to different freshwater fish (Danio rerio, Oncorhynchus mykiss) after exposure to the structurally related carbonate esters dimethyl carbonate (DMC) and ethylmethyl carbonate (EMC), the QSAR Toolbox 3.1.0.21 predicts EC/LC50 values of > 100 mg/l (mortality, abnormal behaviour) for each of the substances, indicating a very low toxicity potential. Whereas most of the experimental as well as calculated values cited here, have to be regarded as not assignable as far as their reliability is concerned, the reported results clearly support the findings of daphnia and algal studies, that dimethyl carbonate is of very low toxicity on aquatic organisms.

In Annex IX of Regulation (EC) No 1907/2006, it is laid down that chronic fish toxicity tests shall be proposed by the registrant if the chemical safety assessment indicates the need to investigate further the effects on fish. According to Annex I of this regulation, the chemical safety assessment triggers further action when the substance or the preparation meets the criteria for classification as dangerous according to Directive 67/548/EEC or Directive 1999/45/EC or is assessed to be a PBT or vPvB. The hazard assessment of diethyl carbonate reveals neither a need to classify the substance as dangerous for the environment, nor is it a PBT or vPvB substance, nor are there any further indications that the substance may be hazardous to aquatic organisms. According to reliable study results, diethyl carbonate is considered to be readily biodegradable in the environment and the bioaccumulation potential is regarded to be insignificant. Therefore, with respect to animal welfare, the performance of acute or chronic fish studies is assumed to be not justifiable.

The calculation of the acute toxicity of diethyl carbonate to fresh and marine water invertebrates yielded 48 h LC50 values ranging from 102.6 to 220.1 mg/L for daphnids and a 96 h LC50=98.3 mg/L for mysid shrimp using ECOSAR v1.00.

The acute toxicity of the structurally related carbonate ester dimethyl carbonate to Daphnia magna was investigated in a study conducted according to EU Method C.2 (Acute Toxicity for Daphnia; 1992). In this static limit test, 20 daphnids were exposed to a nominal concentration of 100 mg DMC/L for 48 h. The concentrations of dimethyl carbonate in the test media were assessed by chemical analyses (GC/FID). Dimethyl carbonate proved to be not toxic to exposed daphnia up to the highest test substance concentration applied and so the 48 h EC50 was set to >100 mg/L and >74.16 mg/L based on the nominal and geometric mean measured concentrations, respectively

For adverse effects to daphnia magna after exposure to the structurally related carbonate esters dimethyl carbonate (DMC) and ethylmethyl carbonate (EMC), the QSAR Toolbox 3.1.0.21 predicts EC50 values for immobilisation of > 100 mg/l for each of the substances, indicating a very low toxicity potential.

In Annex IX of Regulation (EC) No 1907/2006, it is laid down that chronic toxicity tests with aquatic invertebrates shall be proposed by the registrant if the chemical safety assessment indicates the need to investigate further the effects on invertebrates. According to Annex I of this regulation, the chemical safety assessment triggers further action when the substance or the preparation meets the criteria for classification as dangerous according to Directive 67/548/EEC or Directive 1999/45/EC or is assessed to be a PBT or vPvB. The hazard assessment of diethyl carbonate reveals neither a need to classify the substance as dangerous for the environment, nor is it a PBT or vPvB substance, nor are there any further indications that the substance may be hazardous to aquatic organisms. According to reliable study results, diethyl carbonate is considered to be readily biodegradable in the environment and the bioaccumulation potential is regarded to be insignificant. Therefore, the performance of a chronic study with aquatic invertebrates is assumed to be not justifiable.

For the toxicity of diethyl carbonate (DEC) on algae, several study results are reported, both on the substance itself as well as on structurally related carbonate esters, exhibiting in general a low toxicity potential of DEC. For the effect of DEC on the growth of the green alga Scendesmus sp, an EC50 of 70.4 mg/l is predicted by the OECD-Toolbox 3.1.0. The calculation of the toxicity of diethyl carbonate to green algae yielded 96 h EC50 values ranging from 47.6 to 68.8 mg/L and chronic values ranging from 9.3 to 21.6 mg/L using ECOSAR v1.00. The structurally related carbonate ester dimethyl carbonate (DMC) was investigated on its toxic effect towards Selenastrum capricornutum (new name: Pseudokirchnerella subcapitata) in a study conducted according to EU Method C.3 (Algal Inhibition test; 1992). In this static limit test, the algae were exposed to a nominal concentration of 100 mg DMC/L for 72 h. The concentrations of dimethyl carbonate in the test media were assessed by chemical analyses (GC/FID). Dimethyl carbonate proved to be not toxic to exposed algae up to the highest test substance concentration applied and so the 72 h NOEC and EC50 (based on growth rate and biomass) were set to >100 mg/L and > 57.29 mg/L based on the nominal and geometric mean measured concentrations, respectively. These results were supported by values predicted by the OECD-Toolbox 3.1.0 for the algae Scendesmus sp, Scendesmus subspicatus as well as Selenastrum capricornutum (new name: Pseudokirchnerella subcapitata): EC50 and NOEC (endpoints biomass, growth rate) >= 62 mg/l.

According to REACH Regulation (Annex VIII, 9.1.4, column 2) the study on respiration inhibition of activated sludge does not need to be done if the substance is readily biodegradable. Diethyl carbonate proved to be readily biodegradable and fulfilling the 10-d-window criterion (>81% biodegradation after 28 d). In the toxicity control of the ready biodegradability test containing both test and reference item (100 mg/L each), 72% biodegradation occurred within 14 d, thus indicating that the test item was not inhibitory to the inoculum at the concentration tested. Based on these results, the study on respiration inhibition of activated sludge is not regarded as necessary.