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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Reference
Endpoint:
bioaccumulation in aquatic species: fish
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the substance has a low potential for bioaccumulation based on log Kow <=3
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
In accordance with REACH Annex IX, Section 9.3.2, Column 2, bioaccumulation testing need not be conducted if:the substance has a low potential for bioaccumulation. LANXESS (2018 - see Section 13.2 of IUCLID) clearly shows that 2H-Benzimidazole-2-thione, 1,3-dihydro-4(or 5)-methyl-, zinc salt (2:1) (ZMB2), i.e. the registered substance, exhibits its salt characteristic in aqueous solution, i.e., dissolving in water to 1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione (MB2) and zinc ions in a matter of seconds. Therefore, the measured log Pow value for ZMB2 is not considered relevant for bioaccumulation assessment as it will never exist in the aquatic environment. Instead, the data presented for MB2 (log Pow = 0.3 - 0.4) is most relevant for bioaccumulation potential. The low partitioning behaviour of MB2 is consistent with a conclusion of low bioaccumulation potential, and therefore bioaccumulation testing with the registered substance is not considered necessary.

Description of key information

WAIVER: In accordance with REACH Annex IX, Section 9.3.2, Column 2, bioaccumulation testing need not be conducted if:the substance has a low potential for bioaccumulation.  LANXESS (2018 - see Section 13.2 of IUCLID) clearly shows that 2H-Benzimidazole-2-thione, 1,3-dihydro-4(or 5)-methyl-, zinc salt (2:1) (ZMB2), i.e. the registered substance, exhibits its salt characteristic in aqueous solution, i.e., dissolving in water to 1,3-dihydro-4(or 5)-methyl-2H-benzimidazole-2-thione (MB2) and zinc ions in a matter of seconds.  Therefore, the measured log Pow value for ZMB2 is not considered relevant for bioaccumulation assessment as it will never exist in the aquatic environment.  Instead, the data presented for MB2 (log Pow = 0.3 - 0.4) is most relevant for bioaccumulation potential.  The low partitioning behaviour of MB2 is consistent with a conclusion of low bioaccumulation potential, and therefore bioaccumulation testing with the registered substance is not considered necessary.

Key value for chemical safety assessment

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