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A fish bioconcentration study has been done on polysulfides, di-tert-butyl in accordance to an ECHA decision following a testing proposal. Given the properties of the substance, the study has been carried out using the dietary exposure route, according to the protocol described in the OECD Guideline 305, revision 2012.

Freshwater fish Lepomis macrochirus (Bluegill sunfish) were exposed for 14 days to TPS 44 (polysulfide di-tert-butyl) incorporated in the fish diet at a non-lethal level of 100 µg/g, then fed for further 42 days in non-contaminated diet for depuration. Concentrations in fish were measured at selected intervals and BMF was calculated taking account of growth and lipid correction. The resulting BMFkgL is equal to 0.0059.

The appropriateness of the experiment was checked by exposing in parallel a lot of fish to a positive control: HCB (hexachlorobenzene). The results obtained, BMF = 0.7033, is in agreement with historical data in the lab with Bluegill and the observations made during OECD ring test.

From the BMFkgL, estimation of a BCF value was made according to two methods described in the TG 305. The allometric method based on Sijm et al. (1995) was shown to be unsuitable, due to the poor assimilation efficiency of TPS 44 through the gut. An empirical approach based on the work of Inoue et al. (2011) leads, through a linear relationship, to an estimated BCFkgL of 188, one order of magnitude below the threshold set for bioaccumulative substances.