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Ecotoxicological information

Ecotoxicological Summary

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Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:
PNEC aqua (freshwater)
PNEC value:
0.101 mg/L
Assessment factor:
1
Extrapolation method:
sensitivity distribution
PNEC freshwater (intermittent releases):
0.101 mg/L

Marine water

Hazard assessment conclusion:
PNEC aqua (marine water)
PNEC value:
0.101 mg/L
Assessment factor:
1
Extrapolation method:
sensitivity distribution

STP

Hazard assessment conclusion:
PNEC STP
PNEC value:
2.02 mg/L
Assessment factor:
1
Extrapolation method:
sensitivity distribution

Sediment (freshwater)

Hazard assessment conclusion:
PNEC sediment (freshwater)
PNEC value:
7.86 mg/kg sediment dw
Assessment factor:
1
Extrapolation method:
equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:
PNEC sediment (marine water)
PNEC value:
7.86 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:
1.34 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, soil and micro-organisms using the HC5 model plus statistical extrapolation or equilibrium partitioning calculations.

Conclusion on classification

1,3,5-trimethylbenzene has a harmonised classification as Chronic Category 2, with the hazard statement 'Toxic to aquatic life with long lasting effects'.

Experimental data were available for the three trophic levels required for REACH for short term toxicity. These data indicate that the EC50 values range from 6 mg/L for Daphnia, 12.52 mg/L for fish and 25 mg/L for algae. The aquatic invertebrates study by Bobra et al (1983) reports the most conservative acute result.

Experimental data are available for the long term toxicity to aquatic invertebrates, though no experimental data are available for the long-term toxicity to fish and only non-standard experimental data are available for toxicity to algae. The available data indicate a 21 day NOEC of 0.4 mg/L for Daphnia (based on reproduction) and a 48 hour EC10 for algae of 16 mg/L based on growth rate and 8.1 mg/L based on biomass.

The lowest reliable experimental result reported for acute toxicity is 48-hour EC50 for Daphnia magna of 6.0 mg/L. The lowest reliable reported chronic result is 21 day NOEC for Daphnia magna of 0.4 mg/L. 1,3,5-trimethylbenzene is readily biodegradable but failed the 10-day window criterion and therefore cannot be considered rapidly biodegradable in the environment. 1,3,5-trimethylbenzene has a log partition coefficient of 3.42 and therefore is not expected to bioaccumulate and this is supported by the available BCF values of 23 to 342. On the basis of the available data, 1,3,5-trimethylbenzene does not meet the criteria for acute classification. As a non-rapidly degradable substance with chronic toxicity data in the range 0.1-1 mg/L, 1,3,5-trimethylbenzene meets the criteria for classification as Chronic Category 2.