5H-Cyclopenta[h]quinazoline, 6,6a,7,8,9,9a-hexahydro-7,7,8,9,9-pentamethyl-

Bioaccumulation: aquatic / sediment

Description of key information

The substance has a BCFss of 634 L/kg in a study equivalent to OECD TG 305.

Key value for chemical safety assessment

BCF (aquatic species):

634 L/kg ww

Additional information

The potential for bioaccumulation in aquatic species was examined in a study according to OECD TG 305, and in compliance with GLP criteria (Ceri, 2019). In this study, groups of 26 fish (C. carpio) were exposed to nominal test substance concentrations of 5 µg/L (Level 1) and 0.5 µg/L (Level 2) for 28 days in natural freshwater under flow-through conditions. During analytical verification of nominal test concentrations five peaks were detected with GC-MS analysis. The concentration of each peak was described on the basis of initial test item concentration without consideration of the constituent ratio. The bioconcentration potentials of Peaks 1, 3 and 4 were evaluated only for Level 1, because quantitative analyses of these peaks in Level 2 was difficult due to low content rates in the test item (1.5-5.4%). However, at Level 1 the nominal test concentration of 5 μg/L is < 1/2000 of the water solubility of Peaks 1, 3 and 4, and therefore the BCF values determined for Peaks 1, 3 and 4 would not be depended of the test concentration. The authors therefore concluded that the bioconcentration potentials of Peaks 1, 3 and 4 could rely on the result from Level 1 only. Test substance concentrations in test water and test fish were determined at days 11, 18, 20, 25 and 28. The average test item concentration in test fish made on samples taken at the last four successive analyses were within ± 20% of each other for all peaks. Therefore, it was confirmed that steady-state was reached well within the 28 days exposure period. No mortality, or any other clinical and/or other biological abnormalities of fish was observed in the 2 exposure groups and the control. The test validity criteria were met.

The bioconcentration factors at steady-state (BCFss) of the peaks 1 to 5 at Level 1 were determined to range from 180 L/kg (peak 4) to 610 L/kg (peak 1) based on whole body w.w. The BCFss of peaks 2 and 5 at Level 2 were 310 L/kg and 150 L/kg, respectively. The overall highest BCFss, as determined for the main constituent of the test substance, is 610 L/kg. Normalisation to 5% lipid content, provides a BCFss of 634 L/kg, which will be used for risk assessment.