Isobutyryl chloride

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.051 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.512 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.005 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

39 mg/L

Assessment factor:

1

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.415 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.042 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.053 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Additional information

Effect values of the hydrolysis product HCl (CAS 7647 -01 -0) are not considered in the ecotoxicological evaluation of the substance since the observed toxicity is not due to intrinsic properties of the molecule, but is due to pH effects.

Conclusion on classification

Due to the rapid hydrolysis of the parent compound isobutyryl chloride, the assessment will mainly be based on the results for the hydrolysis product isobutyric aicd. Results are availabe for fish (isobutyric acid, LC50 = 146.6 mg/L), invertebrates (isobutyric acid, EC50 = 51.25 mg/L) and algae (isobutyric acid, ErC50 = 53.9 mg/L). Effect values of the hydroysis product HCl (7647-01-0) were not considered in the ecotoxicological evaluation of the substance since the observed toxicity was not due to intrinsic properties of the molecule, but is due to pH effects.

Official classification regarding environment hazards:

Aquatic compartment

In accordance with Regulation (EC) No 1272/2008, Annex VI Table 3.1 or Table 3.2, isobutyryl chloride is not officially classified.

In accordance with Regulation (EC) No 1272/2008, Annex VI Table 3.1 or Table 3.2, isobutyric acid is not officially classified.

Self-classification:

Aquatic compartment

Following DSD/DPD, the hydrolysis product isobutyric acid is not to be classified as dangerous for the environment. The lowest LC/EC50 value is 51.25 mg/L, but the substance is readily biodegradable and the log Pow is < 3 (no experimentally determined BCF).

Following CLP (GHS-EU), the substance is not to be classified as acutely hazardous to the aquatic environment, since the lowest acute effect value is > 1 mg/L.

Chronic data are available only for algae (butyric acid , CAS 79 -31 -2: NOEC > 1 mg/L), therefore classification is based on the available chronic (algae) and acute toxicity (fish and Daphnia) data. The data available for chronic classification are (not adequately) conclusive but not sufficient for classification. The chronic data indicate that butyryl chloride is not to be classified as hazardous to the aquatic environment.The lowest acute effect value is between 10 -100 mg/L (isobutyric acid: Daphnia, 48-h EC50 = 51.3 mg/L). But butyric acid is readily biodegradable and its log Pow is < 4.Therefore, the substance is not be classified as chronically hazardous to the environment.

Atmospheric compartment

The test substance is not listed in Annex 1 of Regulation (EC) 2037/2000 on substances that deplete the ozone layer.

The test substance does not belong to the green house gases listed in P Forster, PV Pamaswamy et al. Changes in Atmospheric Constituents and Radiative Forcing. In: Climate Change 2007: The Physical Basis. Contribution of Working Goup 1 to the Fourth Assessment Report of the Intergovernmental Panel on climate Change.