reaction mass of ethylbenzene and xylene

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.327 mg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

PNEC freshwater (intermittent releases):

0.327 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.327 mg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

6.58 mg/L

Assessment factor:

1

Extrapolation method:

sensitivity distribution

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

12.46 mg/kg sediment dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

12.46 mg/kg sediment dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

hazard related to composition of atmosphere identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

2.31 mg/kg soil dw

Assessment factor:

1

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

PNECs were derived for freshwater, saltwater, sediment, and soil using the Petrotox model or equilibrium partitioning calculations.

The screening criteria for toxicity is that a substance with an acute EC50 or LC50 <0.1 mg/L is considered to potentially meet the T criterion, and that an EC50 or LC50 <0.01 mg/L indicates that the substance is definitely T. The criteria in Annex XIII is that a substance with a chronic EC10 / NOEC ≤ 0.01 mg/L is considered to be T. It is difficult to assess the toxicity of streams using standard test methods as the tests measure the properties of the whole substance. It is more appropriate to consider whether the representative components are toxic and therefore data have been read across from the xylene isomers and ethylbenzene.

The key short-term toxicity to fish result is a 96 hour LC50 of 2.6 mg/L for p-xylene. The key short-term toxicity to invertebrates result is a 48 hour EC50 for Daphnia magna of 3.82 mg/L for o-xylene and a 24 hour EC50 for Daphnia magna of 1 mg/L is also reported for o-xylene. The key short-term toxicity to algae result is a 72 hour ErC50 of 3.2 mg/L for p-xylene and a 48 hour EC50 of 1.3 mg/L is also reported for ethylbenzene. The key long-term toxicity to fish result is a 56 day NOEC of 1.3 mg/L for mixed xylenes. The key long-term toxicity to invertebrates result is a 7 day NOEC for Ceriodaphnia dubia of 0.96 mg/L for ethylbenzene. The key long-term toxicity to algae result is a 73 hour NOEC of 0.44 mg/L for p-xylene.

None of the short-term ecotoxicity results for the xylene isomers or ethylbenzene are less than 1 mg/L and none of the lowest long-term ecotoxicity results are less than 0.1 mg/L. Therefore, based on the screening criteria for environmental toxicity stipulated in the ECHA's Guidance on information requirements and chemical safety assessment [Part C: PBT Assessment (2008)] the toxicity criteria are not met. Therefore, the category members are not considered to be T on the basis of these criteria.

 

Conclusion on classification

The key short-term toxicity to fish result is a 96 hour LC50 of 2.6 mg/L for p-xylene. The key long-term toxicity to fish result is a 56 day NOEC of 1.3 mg/L for mixed xylenes.

The key short-term toxicity to invertebrates result is a 48 hour EC50 for Daphnia magna of 3.82 mg/L for o-xylene. A 24 hour EC50 for Daphnia magna of 1 mg/L is also reported for o-xylene but both this and the key study (48 hour EC50 of 3.82 mg/L) with the same test organism are considered valid. None of the results for short-term toxicity to invertebrates for the xylene isomers or ethylbenzene are less than 1 mg/L. The key long-term toxicity to invertebrates result is a 7 day NOEC for Ceriodaphnia dubia of 0.96 mg/L for ethylbenzene.

The key short-term toxicity to algae result is a 72 hour ErC50 of 3.2 mg/L for p-xylene. A 48 hour EC50 of 1.3 mg/L is also reported for ethylbenzene in the Draft Screening Assessment Report by Environment Canada (2014). None of the results for short-term toxicity to algae for the xylene isomers or ethylbenzene are less than 1 mg/L. The key long-term toxicity to algae result is a 73 hour NOEC of 0.44 mg/L for p-xylene.

None of the short-term ecotoxicity results for the xylene isomers or ethylbenzene are less than 1 mg/L. The lowest long-term ecotoxicity results for the xylene isomers and ethylbenzene are between 0.1 and 1 mg/L. Data on the xylene isomers and ethylbenzene indicates that biodegradation is rapid and that they will partition to the air from water, further reducing their potential for exposure. An experimentally determined BCF for mixed xylenes in fish gave a result of 29, indicating a low potential for bioaccumulation.

These values confirmed that a classification for acute hazard to the environment is not required but a Chronic Category 3 classification is required under the CLP Regulations and this has been added as a self classification to the dossier.