Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

BIOACCUMULATION: AQUATIC / SEDIMENT

The registration substance is a multi-constituent and due to the strongly basic nitrogen atoms present in the different constituents (pKa112.7-14.7 and pKa210.1-13.8, see IUCLID Chapter 4.21) a cationic surfactant. Due to the estimated pKa it is obvious that in the environmental pH range of 4 to 9 the constituents are mono- or di-protonated. The property estimation program US EPA KOWWIN Version 1.68 allows to calculate the Log Kow for the different mono- or di-protonated constituents. The estimated Log Kow values are in the range of -7.5 and 2.8. For the highest Log Kow of 2.8 the US EPA BCFBAF model Version 3.01 calculates a BCF of 31 L/kg wwt (Regression model) and 38 L/kg wwt (Arnot-Gobas model) which means a low potential for bioaccumulation.
For (cationic) surfactants classical measurements like shake-flask (OECD 107), HPLC (OECD 117) or Slow stirring (OECD 123) are not suitable as the result depends form the measurement conditions. Instead the Log Kow may be estimated from the solubility in 1-Octanol and the CMC (Critical micelle concentration). The registration substance is miscible in 1-Octanol in every proportion but this may not reflect the true solubility of the single constituents as the solubility of the mixture is influenced by the various constituents (co-solvency). The Log Kow calculated from the 1-Octanol solubility and the CMC of the registration substance is 3.6 at 20 degree Celsius (see IUCLID Chapter 4.7). This is higher than the highest Log Kow calculated for the different protonated constituents of the registration substance. It is below the ‘B’ criteria of log Kow >4.5 for the PBT / vPvB Assessment. Based on the Log Kow of 3.6 the Exposure modelling program EUSES calculates a BCF fish of 229 L/kg wwt which is below the 'B' criteria of >2000 for the PBT /vPvB Assessment.

CONCLUSION: Based on the measured as well as the estimated Log Kow given above, the registration substance is not bioaccumulative. It is important to note that cationic surfactants strongly sorb to negatively charged surfaces like clays and glass but also to biota (e.g. fish mucous). These properties make a BCF fish study for the registration substance according OECD 305 infeasible.  BIOACCUMULATION: TERRESTRIAL Based on the Log Kow of 3.6 calculated from the 1 -Octanol solubility and the CMC the Exposure modelling program EUSES 2.1 calculates a BCF worm of 49 L/kg wwt. CONCLUSION: Based on the measured Log Kow of 3.6 and the BCF worm of 49 L/kg wwt derived, the registration substance has a low potential for bioaccumulation in soil.