Butyl chloroformate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.082 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

2.25 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.008 mg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

2 476 mg/L

Assessment factor:

1

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.377 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.038 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.027 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Derivation of PNECs

Butyl chloroformate rapidly hydrolyses in contact with water to form butanol (CAS 71 -36 -3), hydrogen chloride (CAS 7647-01-0) and carbon dioxide (CAS 124-38-9). Effect values of the hydrolysis product hydrogen chloride were not considered in the derivation of the PNECs since the observed toxicity was not due to the intrinsic properties of the molecule but rather to pH effects. For the hydrolysis product carbon dioxide no ecotoxicological information is available. Therefore, only the results obtained from tests with the parent substance and the hydrolysis product butanol are considered for derivation of PNECs.

In the acute fish toxicity study with the parent substance butyl chloroformate, rapid hydrolysis to butanol and hydrogen chloride may be expected to have occurred. However, the toxicity in the study with butyl chloroformate is considerably higher than the toxicity observed in the study with the hydrolysis product butanol. Considering that the pH remained within acceptable limits (i.e. no effects expected to be related to the formation of hydrogen chloride), the clearly higher toxicity of butyl chloroformate may be expected to be due to reactivity of un-hydrolysed parent substance at the beginning of the test. On a larger geographical and temporal scale butyl chloroformate may be expected to exist in aqueous environments mainly, if not only, as its hydrolysis products and therefore the short-term reactivity effect is considered likely to be of little relevance for environmental assessment. Therefore, the lowest acute effect value available for butanol is used for derivation of PNECs.

Conclusion on classification

Official classification:

Aquatic compartment

In accordance with Regulation (EC) No 1272/2008, Annex VI Table 3.1, the substance is not officially classified.

In accordance with Regulation (EC) No 1272/2008, Annex VI Table 3.2, the substance is not officially classified.

Butyl chloroformate is expected to rapidly hydrolyse in contact with water to form butanol (CAS 71 -36-3), hydrogen chloride (CAS 7647-01-0) and carbon dioxide (CAS 124-38-9). Therefore, only data on the environmental fate and pathways and data on aquatic toxicity available for the hydrolysis products are considered for self-classification. Effect values of the hydrolysis product hydrogen chloride were not considered for self-classification purposes since the observed toxicity was not due to the intrinsic properties of the molecule but rather to pH effects. For the hydrolysis product carbon dioxide no ecotoxicological information is available.

Self-classification:

Aquatic compartment

Following CLP, the substance is not to be classified as acutely hazardous to the aquatic environment. Based on the available acute and chronic data, the substance is not to be classified as chronically hazardous to the aquatic environment.

 Rationale:

Butanol is qualified as readily biodegradable, according to OECD criteria.

The substance is not classified as acutely hazardous to the aquatic environment, since the lowest acute effect value is >> 1 mg/L (fish: 96 -h LC50 >/= 100 mg/L; O. latipes; nominal; MOE, 1996).

Chronic data are available for two trophic levels (daphnids and algae), therefore classification is based on the available chronic and acute data.

- Chronic toxicity data:

Chronic toxicity data are available for algae and daphnids. The lowest chronic effect value is a 21-d NOEC = 4.1 mg/L; MOE Japan, 1996). According to the criteria outlined in Table 4.1.0(b)(ii) (Commission Regulation (EU) No 286/2011 amending Regulation (EC) No 1272/2008 for rapidly degradable substances) the substance is not to be classified as chronically hazardous to the aquatic environment.

- Acute toxicity data:

The lowest acute effect value is >100 mg/L (fish: O. latipes: 96h LC50 ≥100 mg/L; MOE Japan, 1996); the substance is rapidly degradable and the log Kow is < 4. The substance is not to be classified based on the categories outlined in Table 4.10(b) (iii) (Commission Regulation (EU) No 286/2011 amending Regulation (EC) No 1272/008.

- Conclusion:

Butyl chloroformate (CAS 592-34-7) rapidly hydrolyses in contact with water to butanol (CAS 71-36-3), hydrogen chloride (HCL, CAS 7647 -01 -0) and carbon dioxide (CAS 124-38-9). Butyl chloroformate is expected to rapidly hydrolyse in contact with water to form butanol (CAS 71 -36-3), hydrogen chloride (CAS 7647-01-0) and carbon dioxide (CAS 124-38-9). Therefore, only data on the environmental fate and pathways and data on aquatic toxicity available for the hydrolysis products are considered for self-classification:

 

- Hydrolysis product butanol (CAS 71-36-3):

Based on the available acute and chronic toxicity data for the , the substance is not to be classified as acutely hazardous to the aquatic environment.

 

- Hydrolysis product hydrogen chloride (HCL, CAS 7647 -01 -0):

The hazard of hydrochloric acid for the environment is caused by pH-related effects. For this reason, the effect of hydrochloric acid on the organisms depends on the buffer capacity of the aquatic ecosystem. There is a possibility that the emission of hydrochloric acid could locally decrease the pH in the aquatic environment. However, normally the pH of effluents is measured frequently to maintain water quality and the range of pH can be managed properly to prevent adverse effects on the aquatic environment. Therefore, a significant decrease of the pH of the receiving water is not expected. Generally, the changes in pH of the receiving water should stay within the natural range of the pH, and for this reason, adverse effects on the aquatic environment are not expected due to anthropogenic or naturally occurring hydrochloric acid (OECD SIDS, 2002). For these reasons, hydrogen chloride is not classified for the environment.

 

- Hydrolysis product carbon dioxide (CAS 124-38-9):

For carbon dioxide no information on environmental fate and pathways or ecotoxicological information is available. No substance classification is therefore possible.