3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

5.8 µg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.001 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.58 µg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

7.56 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

1.24 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.124 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:

0.175 mg/kg soil dw

Assessment factor:

10

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The preliminary study showed that at each of pH 4, 7 and 9 and 50±0.5ºC, greater than 50% hydrolysis had occurred after 2.4 hours, equivalent to a half-life of less than 1 day under environmental conditions (25°C).

As a consequence, when release into water 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate will rapidly be transformed into due to its instability. That is the reason why the assessment of the bioaccumulation potential will be based on the bioaccumulation potential of degradation substances: neodecanoic acid and 2-methyl-2,4-pentanediol.

A computer simulation via EPI Suite TM (using an experimental log Kow of 3.2, coming from the Klimisch-1-rated study of GRL 2009, see section 4.7 “Partition coefficient”) gave a BCF for the concerned substance of 274 L/kg wet-wt, which is below the trigger value of BCF = 500 for classification with respect to chronic aquatic toxicity:

Bioaccumulation Estimates (BCFBAF v3.00):

  Log BCF from regression-based method = 2.438 (BCF = 274.3 L/kg wet-wt)

  Log Biotransformation Half-life (HL) = -0.2198 days (HL = 0.6029 days)

  Log BCF Arnot-Gobas method (upper trophic) = 2.345 (BCF = 221.4)

  Log BAF Arnot-Gobas method (upper trophic) = 2.345 (BAF = 221.4)

      log Kow used: 4.20 (user entered)

 

With regards to the two breackdown substances: neodecanoic acid and 2-methyl-2,4-pentanediol a computer simulation via EPI Suite TM was also done.

Neodecanoic acid:

Bioaccumulation Estimates (BCFBAF v3.00):

  Log BCF from regression-based method = 0.500 (BCF = 3.162 L/kg wet-wt)

  Log Biotransformation Half-life (HL) = 0.1593 days (HL = 1.443 days)

  Log BCF Arnot-Gobas method (upper trophic) = 2.548 (BCF = 353.1)

  Log BAF Arnot-Gobas method (upper trophic) = 2.548 (BAF = 353.4)

      log Kow used: 3.90 (estimated)

 

2-methyl-2,4-pentanediol

Bioaccumulation Estimates (BCFBAF v3.00):

  Log BCF from regression-based method = 0.500 (BCF = 3.162 L/kg wet-wt)

  Log Biotransformation Half-life (HL) = -1.4535 days (HL = 0.0352 days)

  Log BCF Arnot-Gobas method (upper trophic) = 0.052 (BCF = 1.127)

  Log BAF Arnot-Gobas method (upper trophic) = 0.052 (BAF = 1.127)

      log Kow used: 0.58 (estimated)

 

Based on the available information it is therefore proposed that the study on bioaccumulation of 3-hydroxy-1,1-dimethylbutyl peroxyneodecanoate and its degradation substances can be waived.

Conclusion on classification

The information concerning the aquatic toxicity are summarized hereafter:

* The acute toxicity of 3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate was evaluated with Cyprinus carpio in a study performed in accordance with OECD testing guideline 203 and GLP requirements.The LC50-value decreased from 2.5 mg/L after 24 hours of exposure to 1 mg/L at the end of the 96 -hour exposure period. Hence, no stabilization of effects was observed at the end of the test period.

*The chronic toxicity was assessed with Pimephales promelas in accordance with OECD Guideline No. 210 and GLP requirements. The lowest NOEC was obtained for the post-hatch survival corresponding to 0.058 mg a.i./L.

* The acute toxicity of 3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate was evaluated with Daphnia magna in a study performed in accordance with OECD testing guideline 202 and GLP requirements. The substance did not induce acute immobilization of Daphnia magna at or below 1.8 mg/L after 48 hours of exposure (NOEC) with a 48h-EC50 of 4.8 mg/L (95% confidence interval between 4.2 and 5.8 mg/l).

* The long-term toxicity test with Daphnia magna has been performed according to OECD testing guideline 211 and GLP requirements. After 21 days of exposure, the 21 days EC10-reproduction was 0.84 mg/L a.i..

*The acute toxicity of 3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate was evaluated with Pseudokirchneriella subcapitata in a study performed in accordance with OECD testing guideline 201 and GLP requirements.The E_rC₅₀ (0 - 72 h)was estimated at 9.13 mg/L and theE_rC₁₀ (0 - 72 h) at 0.496mg/L.

* On the top of that the substance is not readily biodegradable and its log Kow was estimated at 4.2.

The aquatic hazard classification based on these data according to CLP criteria (Regulation No 1272/2008) is:

Category Acute 1, M-factor = 1

Category Chronic 1, M-factor = 1