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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Calculation with BCFBAF v3.01 (EPIWIN software by US-EPA): 70.8 L/kg wet-wt, strong bioaccumulation is not expected.

Key value for chemical safety assessment

BCF (aquatic species):
70.8 L/kg ww

Additional information

The "Reaction Products of alcohols, C14-18, C18 unsat., esterified with phosphorus pentoxide and salted with amines, C12-14,-tert-alkyl"

has a predicted Bioconcentration Factor (BCF) of 70.8 L/kg (Chemservice S.A., 2013) and partition coefficient (logPow) of > 5.66 at 20 °C (Fox, 2013) strong bioaccumulation in aquatic biota is not expected. Only limited bioaccumulation is assumed for compounds with a logPow < 4.5 or > 6 (based on ECHA REACH Guidance R.11 PBT Assessment). Concerning logPow exceeding 6, a gradual decrease of the Bioconcentration Factor (BCF) is observed practically. Examples are discussed in a literature study of the German Federal Environment Agency (Umweltbundesamt (Ed.): Comparative analysis of estimated and measured BCF data (OECD 305). Report No. (UBA-FB) 001435/E, ISSN: 1862-404, Dessau, March 2011).

For large lipophilic molecules (as the target UVCB substance), the molecular weight can be potential candidate for use as cut-off trigger for B/vB compounds, since substances with a molecular weight >600 revealed decrease in BCF values (BCF < 1000, hence below the REACH trigger values for B/vB). For details, refer to p. 31 of Fraunhofer Report FKZ36001043 (Literature study: Effects of molecular size and lipid solubility on bioaccumulation potential; Fraunhofer Institut Molekularbiologie und Angewandte Oekologie, Schmallenberg, Germany, February 2007).

Furthermore, it has been hypothesized by different authors in publications that a high logPow is more an effect of solubility than lipophilicity of the substance. In conclusion, according to REACH, Annex IX, Section 9.3.2 (column 2), this endpoint can be waived.

The Bioconcentration Factor (BCF) of Reaction Products of alcohols, C14-18, C18 unsat., esterified with phosphorus pentoxide and salted with amines, C12-14,-tert-alkylwas determined by calculation using two representative structures of the UVCB substance (Chemservice S.A., 2013). This calculation was performed by the computer program from US-EPA (EPIWIN software BCFBAF v3.01). Furthermore, the whole body primary biotransformation rate estimation for fish was calculated by the same program with the notation that the bio half-life is normalized to 10 g fish at 15 °C. With this result it is possible to predict the apparent metabolism half-life in fish for three different trophic levels (lower, mid and upper). In general, the bioconcentration factor of a substance describes the accumulation potential of a substance dissolved in water by an aquatic organism. BCFBAF v3.01 calculates also the BAF (Bioaccumulation factor) of the chemical, which is defined as the steady-state (equilibrium) ratio of the substance concentration in an organism to the concentration in the surrounding medium. However, this value is not taken into account for the risk assessment and is not relevant for a registration under REACH Regulation (EC) 1907/2006. For both representatives structures, the BCF is given as 70.80 L/kg using the regression-based estimate (traditional method).Using the Arnot-Gobas method, which is based on mechanistic first principles, an aquatic BCF of 76.66 L/kg wet-wt is the result for the first representative structure.Using the second one, a value of 0.89 L/kg wet-wt is given as result.    

Concerning the first representative structure, the whole body primary biotransformation rate estimate for fish results in a half-life of 21.51 days. For the second representative structure, the value is given as 1.115E+4 days. For these predictions, the bio half-life is normalized to 10 g fish at 15 °C. The corresponding rate constants (kM) are 3.22E-2/day for the first structure and 1.704E-7/day for the second one. This is taken into account to predict the apparent metabolism half-life in fish of the first representative structure. With the Arnot-Gobas method it is possible to differentiate between three trophic levels. For the first representative structure, the BCF for the lower trophic level is given as 6.56 L/kg, for the mid trophic level as 6.02 L/kg and for the higher one as 4.58 L/kg. The second representative structure reveals values of 0.94 L/kg, 0.93 L/kg and 0.89 L/kg for the lower, mid and upper trophic level, respectively. As conclusion it can be stated, that strong bioaccumulation in aquatic organisms is unlikely.

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