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Description of key information

The bioconcentration factor (BCF) for earthworms is calculated using measured LogKow data as there is no experimental data available.  The LogKow is provided by Sasol (see Section 4.7; Partition Coefficient) with a value of 5.4, which results in a calculated BCF of 3015.  This BCF results in a default biomagnification factor (BMF) of 2 (based on default aquatic BMF).

Key value for chemical safety assessment

BCF (terrestrial species):
3 015 dimensionless

Additional information

Determination of a bioconcentration factor (BCF) followsGuidance on Information Requirements and Chemical Safety Assessment Chapter R.16: Environmental Exposure Estimation (ECHA 2008) and Chapter R. 7c Endpoint Specific Guidance (ECHA 2008). Chapter R.16.5.3.5 states that there may be bioaccumulation potential if log Kow is >3. The log Kowof nonylphenol is provided by Sasol as 5.4 (see Section 4.7). Therefore, as per REACH Annex IX, bioaccumulation information must be presented forsubstances manufactured or imported in quantities of 100 t/y or more.

 

Chapter R.7c states that BCFs can be determined experimentally, by calculation using Kow, or by estimating using BCF models such as QSARs. There is no experimental data available for terrestrial organisms so the BCF is calculated using theKow. The BCF is calculated using the ECHA Equation R.16-76, which is BCF earthworm = (0.84+0.012Kow)/RHO earthworm. The RHO earthworm by default value of 1 (kg wwt/L) can be assumed.

Calculated BCF

BCF earthworm = (0.84+0.012Kow)/RHO earthworm

BCF calculation using logKow of 5.4 (Kow is 251188.64)

BCF earthworm = 0.84+(0.012*251188.64)/1

BCF earthworm = 3015.1

The BCF of 3015 for earthworms indicates that nonylphenol has a tendency to accumulate in terrestrial organisms. This value is recommended for nonylphenol bioconcentration in this risk assessment.