Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

A flow-through bioconcentration study with bluegill Sunfish (Lepomis macrochirus) following OECD Guideline 305 was conducted in 1998 following GLP. This study results can be summarized as follows: Total [14C] residue concentrations in all fish tissue portions (based on wet weights) reached steady state (equilibrium) by Day 3 at both exposure concentrations. The whole body BCF for fish exposed to a mean measured steady state concentration of 0.00519 mg/L was 194X. The whole body BCF for fish exposed to 0.0517 mg/L was 183X. The rate of elimination was initially rapid. The biological half-life of the total [14C]residues was < 24 hours. After 24 hours, > 70% of the whole body residues present on the last day of exposure had been eliminated from the fish exposed at both test concentrations. [14C]Residue representing parent compound was determined in an extracted whole body fish tissue sample, collected from the metabolite aquarium at the end of the uptake phase of the study. The mean measured exposure concentration in this test aquarium was 0.0491 mg/L. The analysis of this sample revealed that the test substance was extensively metabolized. Approximately 1.0% of the total residues represented parent compound. The measured concentration of 0.0956 mg/kg was used to calculate a BCF of 1.95X.

Overall the available data indicate some, but limited potential of TXIB to bioconcentrate in aquatic species.