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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Biodegradation in water: screening tests

There are several higher tier biodegradation studies available assessing the biodegradation of the test substance in water and sediment, and in soil showing a moderately fast degradation/dissipation. However, in the light of the principle of precaution and the worst case the substance is thus regarded to be not readily biodegradable.

Biodegradation in water and sediment: simulation tests

The anaerobic aquatic metabolism of 14C-labelled test substance (diflufenzopyr) was studied in sediment and pond water. During the study the primary metabolite (difluoroaniline metabolite) reached a maximum concentration of 22% TAR (total applied radioactivity) by day 61 and decreased to 1% TAR by 187 DAT. The DT50 of the metabolite difluoroaniline was 27.4 days. The intermediate metabolite BH 654-5 ranged from 0.6% to 8% TAR and at 187 DAT accounted for less than 1% TAR. The present study showed that the test substance is rapidly degraded under anarobic conditions. The DT50 of the test substance was reported to be about 7.5 days. The half-lives in water and sediment were determined to be 5.75 d at 25 °C and 7.87 d at 25 °C, respectively.

Biodegradation in soil

The test substance (diflufenzopyr) degraded with a moderate rate under aerobic conditions with a half-life of about 18 days. The test substance degraded to a number of products. Metabolites M1 (8-Methyl-5-hydroxy-pyrido(2,3 d)-pyridazinone), M9 (8-Methylpyrido(2,3-d)pyridazine-2,5(1H,6H)-dione) and CO2 were the only degradation products found in excess of 10% TAR (total applied radiation) during the course of the study.