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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

DCPD is not readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

A study for DCPD/Codimer Concentrate (CAS 68478-10-4) was available for review (Exxon Mobil, 2004) and was considered suitable for read across. The ready biodegradability study using activated sludge following OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) showed no biodegradation after 28 days. TheDCPD/Codimer Concentrate consists of dicyclopentadiene and codimers of cyclopentadiene. The substance consists of DCPD along with lower concentrations of other codimers of cyclopentadiene which have similar structures to DCPD and are expected to have similar biodegradation properties. Therefore, read across of this conservative result to DCPD is considered robust.

Information from MITI Japan indicating that the substance was not readily biodegradable was unavailable for review. However, this study is from a regulatory source and has been used in the OECD SIDS and therefore is included as a supporting study.

The use of a QSAR to predict the biodegradability of 3a,4,7,7a-tetrahydro-4,7-methanoindene is an appropriate technique to use as part of a weight of evidence approach. The use of BioHCwin and Biowin is appropriate for 3a,4,7,7a-tetrahydro-4,7-methanoindene as this compound clearly falls within the applicability domains of these models as all substructures in 3a,4,7,7a-tetrahydro-4,7-methanoindene are included in the models. The results from both QSAR indicate that 3a,4,7,7a-tetrahydro-4,7-methanoindene is expected not to be readily biodegradable.