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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The estimated BCF value of C16-C18 TMAC was found to be 70.80 L/kg ww, indicating a low potential to bioaccumulate. The Log BCF value was 1.85. This is supported by an experimental BCF value of 79 determined for the read-across substance C12-C16 ADBAC in bluegill fish.

Key value for chemical safety assessment

BCF (aquatic species):
70.8 L/kg ww

Additional information

The bioaccumulation potential of C16 -C18 TMAC was estimated using the BCFBAF v.3.01 model of EPIWEB v.4.1. BCF values were calculated for the individual components using the BCFBAF v3.01 program. The final BCF value was calculated on a weighted-average basis using the mole fractions of all the individual components. The estimated weighted average BCF value was found to be 70.80 L/kg ww. The Log BCF value was 1.85 (U S EPA, 2012).

In a guideline study, the bioaccumulation potential of the read-across substance C12-C16 ADBAC inLepomis macrochirus(bluegill fish) was determined (Fackler PH, 1989). Bluegill fish were continuously exposed to a nominal concentration of 0.050 mg/L of the test substance (equivalent to a measured concentration of 0.076 mg/L) in well water for 35 days, after which 35 fish were transferred to flowing, un-contaminated water for a 21 day depuration period. Sampling intervals for the exposure period were Days 0, 1, 3, 7, 9, 10, 14, 21, 23, 28 and 35 and Days 1, 3, 7, 10, 14 and 21 for the depuration period. Water samples were collected on Day 8 of the exposure period and Day 16 of the depuration for analytic determination of the test substance concentration. Radiometric analyses of the water and selected fish tissues revealed the following:

-        The mean steady state BCF factors in the edible, non-edible and whole body tissue during the 35 days of exposure were determined to be 33, 160 and 79,

-        Half-life for non-edible tissue was attained between Days 14 and 21. By Day 21, the fish had eliminated 29, 60 and 44% of the14C residues that had been present on the last day of exposure in each of the tissues (i.e., edible, non-edible and whole body tissues respectively),

-        The concentration of residual test substance on the skin was observed to be higher than that found in the total edible tissue (skin and muscle combined) indicating significant binding of the test substance to skin and scales of fish. In conclusion the whole body BCF of the test substance was determined to be 79, indicating a low potential to bioaccumulate.