2-methylbutyl acrylate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.011 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

10 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.013 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.001 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.001 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Additional information

Using available ecotoxicological data, the PNECs were calculated to be 0.0004 mg/L for Freshwater and 0.00004 mg/L for Marine Water.  For the calculation of the Freshwater and Marine water PNECs; a 72-hour NOEC value of 0.04 mg/L was obtained from a study with Pseudokirchneriella subcapitata. Chronic studies were not conducted on the most sensitive acute species. Therefore, an AF of 100 was applied to the algae NOEC, which is the lowest of the two long-term NOECs.  An assessment factor of 1000 was applied to these results for the Marine Water PNEC. For the freshwater (intermittent) PNEC, the lowest of three acute values, the 96-hr LC50 of 1.09 mg/L for Pimephales promelas, was used with an AF of 100 to obtain a value of 0.0109 mg/L  For the STP PNEC, a NOEC of 100 mg/L was available for activated sludge respiration inhibition.  An assessment factor of 10 was applied to the NOEC to derive a PNEC for STP of 10 mg/L.  No toxicity test results were available for Sediment or Marine Sediment organisms; therefore the Equilibrium Partitioning Method (EPM) applied to the Freshwater and Marine PNECs was used to derive sediment PNECs.  The Koc was calculated from the laboratory-derived Kow to be 282 L/kg.  The PNECs for Sediment and Marine Sediment were calculated to be 0.0028 mg/kg and 0.00028 mg/kg (based on wet weight), and 0.0129 mg/kg and 0.00129 mg/kg (based on dry weight), respectively.  For Grassland and Agricultural soil, no testing results were available.  The EPM method applied to the Freshwater PNEC was used to derive soil PNECs.  Using the calculated Koc, the PNEC for Grassland and Agricultural soil was determined to be 0.0012 mg/kg based on wet weight and 0.00136 mg/kg based on dry weight.  CAS # 44914-03-6 was found to be readily biodegradable and the log Kow was < 3.0.  Therefore, the PNEC oral is not applicable and was not derived.

2-MBA is not listed in the Montreal Protocol on Substances that Deplete the Ozone Layer. It does not contain reactive halogens (chlorine or bromine) that could play a role in ozone depletion. 2-MBA is not hazardous to the ozone layer.

It should be noted that CAS 44914-03-6 (2-MBA) is included as part of a harmonized group entry whose CLP classification is entered in Annex VI. Consideration as part of the group entry was based on the general hazard characteristics of acrylate esters, since no specific data were available for 2-MBA when classifications were assigned.   This group entry reference number is 607-133-00-9 and the group is described as "monoalkyl or monoalkylaryl esters of acrylic acid with the exception of those specified elsewhere in this annex". The group 607-133-00-9 classification is Aquatic Chronic 2, H411. Environmental data for 2-MBA itself has demonstrated that this substance should receive a classification different from the group entry. We propose a self classification of Aquatic Chronic 3 (H412) based on biodegradation and ecotox data generated using 2-MBA.

Conclusion on classification

CLP: Self classification: Aquatic chronic 3 (H412)

CLP Harmonized Group: Annex VI: Aquatic chronic 2 (H411)

DSD: Self classification: Not classified

DSD: Harmonized Group Annex VI: N;R51/53