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Environmental fate & pathways

Endpoint summary

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The bioconcentration factor (BCF) of the source substance  ( which is the racemic form of the registered/target substance) in the rainbow trout was determined to be 560 and the depuration half-life was determined at 2.0 days (OECD Guideline 305). Nevertheless, this result seems to be overestimated because the BCF was based upon total radiolabelled residues without separating the degradation of the substance from that of the metabolites over the 28 day (maximum accumulation in fish) and 35 day (total depuration) test period. In many cases metabolites are incorporated into the fish tissue in the same way as food and a BCF of 560 can be considered as a worst case value.

In addition, an in vitro biotransformation assay using liver S9 fractions and hepatocytes from rainbow trout (Oncorhynchus mykiss) was performed on the registered substance. Based on the results of this study, the predicted in vivo BCF values using the model of Nichols et al., 2013, were determined at 363 and 196 for the RT-S9 and RT-HEP assays, respectively. 

Based on data available on the source substance, the average BCF value was determined at 373. The result indicates that the registered substance did not bioaccumulate in the rainbow trout.

Additional information