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Environmental fate & pathways

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Phototrasformation in air

No data is available regarding the phototrasformation in air for 6-chlorohexyl methacrylate but it is expected to be similar to short chain alkyl methacrylates (see document "Read -across hypothesis and justification" in section 13 of this IUCLID dossier). In SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004) a general consideration is reported: model calculations indicate that the esters will be rapidly photolyzed in the atmosphere under the influence of atmospheric OH radicals.

 

Hydrolysis

No data is available regarding the stability in water of 6-chlorohexyl methacrylate but its behaviour in water is expected to be similar to short chain alkyl methacrylates and in particular to the most similar substance 2-ethylhexyl methacrylate CAS 688-84-6 (see document "Read -across hypothesis and justification" in section 13 of this IUCLID dossier). As reported in SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004) methacrylate esters are stable at neutral and acidic pH. Under alkaline conditions at pH 9 or 11 significant hydrolysis is observed with a trend to a decrease of the hydrolysis rate with increasing chain length and branching. This is partly due to increased steric hindrance and partly due to decreasing alkoxide stability during ester cleavage. Under normal environmental conditions, abiotic degradation by hydrolysis is not expected to play an important role in the degradation of methacrylates in the environment. In particular, experimental data are available for the most similar short chain alkyl methacrylates 2-ethylhexyl methacrylate (2-EHMA) CAS 688-84-6. In SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004) inside the specific section of 2 -EHMA a study conducted in 1997 according to OECD 111 is reported: 2-EHMA was stable at pH 4 and at pH 7 at 50 °C and the half life for this substance at pH=9 at T=25°C was 58.7 days. (Ref. CERI, 1998, Report No. 80670DK, CERI, Chemicals Evaluation and Research Institute, Japan, unpublished data on 2-EHMA).

 

Biodegradation

No experimental data for 6-chlorohexyl methacrylate is available to assess the biodegradation in water of this substance. The substance is predicted no ready biodegradable by BIOWIN 4.10 using the smile notation ClCCCCCCOC(=O)C(=C)C. A different values regarding the biodegradability was indicated for the group of similar substance short chain alkyl methacrylates and in particular for the most similar substance 2-ethylhexyl methacrylate CAS 688-84-6 (see document "Read -across hypothesis and justification" in section 13 of this IUCLID dossier). In fact, in SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004) the esters of the category are rapidly biodegraded and completely mineralized. In particular, experimental data are available for the most similar short chain alkyl methacrylates 2-ethylhexyl methacrylate (2-EHMA) CAS 688-84-6. In SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004) inside the specific section of 2 -EHMA a study conducted in 1998 according to OECD 301C is reported: 2-EHMA is ready-biodegradable based on 88% of biodegradation in water registered after 28 days (Ref. CERI, 1998, Report No. 20670D, CERI, Chemicals Evaluation and Research Institute, Japan, unpublished data on 2-EHMA).

Based on the similar physical-chemicals properties of 6-chlorohexyl methacrylate and 2-ethylhexyl methacrylate and based on experimental data reported for all short chain alkyl methacrylates in SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004), 6-chlorohexyl methacrylate is reasonably ready-biodegradable as all the other methacrylates. The prediction of BIOWIN 4.10 for 6-chlorohexyl methacrylate is very precautionary and it is not supported by experimental data for similar substances. As conclusion 6-chlorohexyl methacrylate is considered ready-biodegradable.

Bioaccumulation: aquatic

No experimental data for 6-chlorohexyl methacrylate is available to assess the bioaccumulation potential of this substance. The predicted BCF for the substance using BCFBAF v.3.01 (regression-based method) is 197.7 l/kg wet wt using the smile notation ClCCCCCCOC(=O)C(=C)C.

Low potential of bioaccumulation for 6-chlorohexyl methacrylate is expected based on the similarity with short chain alkyl methacrylates and in particular with 2-ethylhexyl methacrylate CAS 688-84-6 (see document "Read -across hypothesis and justification" in section 13 of this IUCLID dossier). In fact, as reported in SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004), despite positive and high logKow for short chain methacrylate esters (for example experimental 2-ethylhexyl methacrylate log Kow= 4.95-5.99) they has got a low experimental BCF. In the specific case of 2-ethylhexyl methacrylate (2-EHMA) in SIDS Dossier of " Short chain alkyl methacrylates" approved at SIAM 18 (20-23 April 2004) is reported a BCF =37 in a fish concentration test (Ref. Schäfers, 2006, Fish, Bioconcentration of 2-Ethylhexyl methacrylate according to the OECD-Guideline 305, Report No. MPA-001/4-10, study on behalf of Methacrylate Producers Association, unpublished report).

The predicted low potential of bioaccumulation for 6-chlorohexyl methacrylate is supported by experimental data for the similar substances short chain alkyl methacrylates and in particular by the data for 2-ethylhexyl methacrylate.

 

Bioaccumulation: terrestrial

No data available.