Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Bioaccumulation: aquatic / sediment

Description of key information

Reduced bioaccumulation

Additional information

Exposure of carp to to 50 and 500 μg/L octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate during 42 days resulted in a bioaccumulation factor of <12 L/kg and <1.2 -8.4, respectively. Concentrations in water were determined by HPLC (CERI 1997). However the test was performed at a concentration in excess of the water solubility of the substance in presence of a dispersant. Therefore the available information does not allow a conclusion on bioaccumulation. However, with the known solubility of the substance (2.85 μg l-1 ), the old Japanese bioaccumulation study can be reassessed. Assuming that in both cases the fish were exposed to saturated aqueous solution, the BCF values can be recalculated as <210 l/kg in the lower concentration and <210-1470 in the higher concentration. Gakushuin (1986) carried out a bioconcentration study with 3-(3-tert.-butyl-4-hydroxy 5 -methyl-phenyl)-propionic acid in accordance to OECD 305C. The substance is closely related to metilox acid. At the end of an 8-week exposure period, the BCF at a test concentration of 0.5 mg/L was <0.4, and at a test concentration of 0.05 mg/L the BCF was <4.3.

Gakushuin (1988) performed also a bioconcentration test with a hindered phenol derivative reaction mass. In this study, a bioconcentration factor was also determined for metilox acid that occurred in the test water as a metabolite. This bioconcentration factor was based on the metilox acid concentration in test water and should be considered worst-case as metilox acid was additionally formed from parent substance in fish body. The bioconcentration factor was determined to be 94-108 at high exposure concentration (1 mg l-1 of parent) and 373-532 at the lower exposure concentration (0.1 mg l-1 of parent).

Calculations of the BCF with standard QSARs (EPISuite 4.00) resulted in low BCF values (BCFBAF v3.00, regression based estimate: BCF = 5.77 L/kg; Arnot-Gobas method (including biotransformation rate estimates: BCF 0.8954 L/kg). A calculated BAF value indicates similar low accumulation properties as suggested by BCF (BCFBAF v3.00, Arnot-Gobas method, including biotransformation rate estimates, upper trophic: BAF 2.975 L/kg). Furthermore, the maximum diameter is markedly above the OSIRIS cut-off criterion of 17Ä, with a of diamax 35.78 Ä (OASIS Catalogic v5.10.6). Therefore, the substance itself is unlikely to cross biological membranes.