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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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biodegradation in water: simulation testing on ultimate degradation in surface water
Data waiving:
other justification
Justification for data waiving:
Justification for type of information:
By the deadline of 7 March 2019, as specified by ECHA decision SEV-D-2114362735-43-01/F, the requested study (simulation testing on ultimate degradation in surface water, OECD guideline 309) is not yet available. Extensive preliminary studies were undertaken, in order to investigate dissolution behaviour, extraction methods, and analytical methods. The schedule as communicated in the most recent dossier update on 07 March 2019 anticipated the definitive study to be started in May 2019, with availability of results by November 2019. However, further complications arose in the preliminary experiments, resulting in a corresponding extra delay. The technical problems could be resolved by November 2019, so that the definitive study could now be started (study plan signed 11 November 2019). Depending on the need to identify known and/or unknown metabolites, and their number, availability of results can be expected between March 2020 and approximately August 2020.
Overall, the simulation study is significantly delayed for technical reasons:
Testing of degradation was planned according to a schedule (initial lab quotes inquired in August 2017) that would have allowed availability of the report by January 2019. However, the start of the study had to be postponed. Despite a water solubility of 0.43 mg/L as established in a guideline study (OECD 105, column elution method, see IUCLID section 4.8), stable concentrations in surface water in the range 0.01–0.1 mg/L (10–100 µg/L) as required for OECD 309 testing could not be maintained in the preliminary tests. The reasons for this may be, possibly amongst others, different salinity, OC content, microbial load of surface water, and deviating solubilisation behaviour at 12 °C. In consequence, the lab has spent several months establishing a technique for generating stable, reproducible test substance concentrations, and a promising approach was identified only very recently (January/February 2019).
Following this initial phase of preliminary experiments, additional technical problems arose, further delaying the start date for the definitive study from May 2019 to November 2019 (see attached status report by the performing laboratory).
Accordingly, the requested study is not yet available. Since a decision on P/vP properties is currently not possible, this formally constitutes a "not P/vP" conclusion, necessitating a dossier update by 9 December 2019. Information on the endpoint in question cannot be submitted at present, constituting waiving circumstances. Nevertheless, the requested study has been started, with an anticipated finalisation date as stated above (range: March–August 2020, depending on the extent of analytical work on potential metabolites).
The justifications for the delayed testing schedule by the laboratory are attached to the current IUCLID summary.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion