Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Aquatic biodegradation:

For the assessment of the bioconcentration potential three studies were available, one of which clearly presented the most complete, reliable and relevant data. In this study, bluegill fish (Lepomis macrochirus) were exposed to a mean concentration of 32 µg/L of the mixture of hydrogenated terphenyl, partially hydrogenated quater- and polyphenyls, and terphenyl in a flow through system for 42 days, after which a depuration phase of 42 days took place. The bioconcentration factors for the mixture of hydrogenated terphenyl, partially hydrogenated quater- and polyphenyls, and terphenyl)

whole substance) calculated for wholefish and muscle tissue were 2000 (3000 Biofac) and 700 (1300 Biofac), respectively. The uptake and depuration rate constants, T1/2 and time to equilibrium for whole fish were calculated by the Biofac model to be 192 L/kg/day, 0.06 days-1, 11 days and 3 days, respectively.

It should be noted though that the relevance of this study is mainly situated in the results of the responses of group I (representing probably o-terphenyl and some terphenyl with one ring saturated) and group II (mixture of terphenyls with one and two rings saturated). For group I, the mean exposure concentration was 1.5 µg/L and the calculated BCFs were 5200 (9100 Biofac) and 2000 (3100 Biofac) for wholefish and muscle tissue, respectively. For group II the mean exposure concentration was 19 µg/L and the calculated BCFs for wholefish and muscle tissue were 2400 (3700 Biofac) and 800 (1200 Biofac), respectively.

Aim of a further key study (Schlechtriem et al., 2017) was to evaluate the use of column-generated analyte concentrations (CGACs) for fish BCF studies with hydrophobic organic chemicals (HOCs). The test followed basic parameters of guideline OECD 305. A solid-phase desorption dosing system was developed to generate stable concentrations of HOCs without using solubilizing agents. In the flow-through tanks a continuous flow of approximately 22 L/h (first study) or 21 L/h (second study) was maintained throughout the test, equivalent to 7.5 volume replacement and 7.2 volume replacement, respectively, per day. In both studies, the test groups were exposed for 56 d (uptake period) and then transferred into a new aquarium where the fish were kept in clean water (depuration period), which was constantly replaced at the same rate as the previously applied test medium. The depuration periods were 28 d and 56 d during the first and second BCF studies, respectively. A kinetic BCF of 12040 (L/kg wet wt) was determined for o-Terphenyl, indicating the bioaccumulation potential of the compound. The tested solid-phase desorption dosing system is suitable to provide stable aqueous concentrations of HOCs required to determine the bioconcentration in fish and represents a viable alternative to the use of solubilizing agents for the preparation of test solutions.

The available supporting study (MITI 2004) was also indicative of the bioaccumulative potential of the substance. This is however currently a K4 study since the original study report is not available.

Terrestrial bioaccumulation

No relevant information available.

Additional information