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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

For the protonated form of Dicyclohexylamine, BCF of 3.2 was estimated indicating that there is no significant bioaccumulation potential of dicyclohexylamine in aquatic organisms.

Key value for chemical safety assessment

BCF (aquatic species):
3.2

Additional information

There are no experimental data on the aquatic bioaccumulation of dicyclohexylamine, but the bioconcentration factors for the neutral and the protonated forms of dicyclohexylamine were calculated with accepted method BCFWIN program (v2.15), using the octanol-water partition coefficients. For the neutral form a BCF of 459 was calculated using the log Kow of 4.37. For the protonated form a BCF of 3.2, using the log Kow of 1.26, was obtained (Bayer Industry Services, 2005e).

Recalculated bioaccumulation using the latest BCFBAF v3.00 is estimated as BCF =353 L/kg wet-wt (Log BCF from regression-based method = 2.55), the result is comparable to value reported by Bayer Industry Services, 2005e.

The partition coefficient was determined also experimentally according to Method A.8, Partition coefficient, Council Regulation (EC) No 440/2008, Published in O.J. L 142, 2008. In accordance with the estimated values of log POW(3.69±0.21), it was decided to use the LC/MS method for partition coefficient determination. The partition coefficient of the test substance Dicyclohexylamine log P = 2.724 0.325 was measuredat 25 °C and pH = 6.7 (Research Institute for Organic Syntheses Inc., 2010). According to results of the ACD/I-Lab’s estimation of the pKa (calculated pKa =11.43) it can be concluded that the test substance exists in its ionisable form below pH ca. 12.4, the Dicyclohexylamine is under prevailing environmental conditions in ionisable form (Research Institute for Organic Syntheses Inc., 2010).

Estimated bioaccumulation (BCFBAF v3.00) using the measured log P, log P = 2.724 measured at pH 6.7 ((Research Institute for Organic Syntheses Inc., 2010) was BCF = 29.13 L/kg wet-wt (Log BCF from regression-based method = 1.464). The bioconcentration factor is very low, but comparable to BCF value for protonated form reported by Bayer Industry Services, 2005e.