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Ecotoxicological information

Long-term toxicity to fish

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Endpoint:
fish early-life stage toxicity
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Endpoint:
fish short-term toxicity test on embryo and sac-fry stages
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Endpoint:
fish, juvenile growth test
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Description of key information

 Waived: Outcome of CSA indicates no need for further investigation

Key value for chemical safety assessment

Additional information

Based on the following rationale a long-term toxicity study in fish is not necessary. 

In accordance with column 2 of REACH Annex IX, the long-term toxicity testing on fish shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on aquatic organisms. Due to rapid biodegradation and the lack of significant bioavailability and the inability to traverse biological membranes it is unlikely that significant long-term exposure to pelagic organisms would occur.

MMT[EHTG] has been characterised as readily biodegradable. The Log Koc and Log P values, 8.46 and 10.98, respectively, are indicative of a marked potential to partition to sediment. Based on Level III fugacity modelling it is estimated that the majority of MMT[EHTG] will partition into sediment [71 %] with a small amount remaining in the water column [16.5 %]. For molecules with Log Kow values exceeding 6.0 it has been shown that the relationship between octanol-water partition coefficients and bioaccumulation breaks down [Banerjee, S. and Baughman, G.L. (1991). Bioconcentration Factors and Lipid Solubility. Environ. Sci. Technol.25: 536-539]. It is hypothesised that these high molecular weight hydrophobic compounds cannot traverse the cellular or gill membrane of aquatic species or lipid membranes for terrestrial species. In addition to molecular weight size exclusions, it is likely that these large hydrophobic molecules are subject to physical-chemical process such as aggregation, flocculation and adsorption to particulates and organic matter that effectively limits bioavailability. 

Thus, due to rapid biodegradation and the lack of significant bioavailability and the inability to traverse biological membranes it is unlikely that significant long-term exposure to pelagic organisms would occur. As such a long term aquatic toxicity study on fish is not considered necessary.