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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

No biodegradation tests have been performed in sediment and in water. The half-life in water can be calculated from the half-life of the biodegradation  test (Modified Sturm test and Zahn-Wellens test), although this may be just an approximation. The various degradation results showed degradation of 1 - 48 % (average 24.5%). 24.5% in 28 days results in a half-life of approximately 60 days, which is considered a worst case assumption, as TGIC has a  hydrolysis half-life of 6.6 days in water. 
The half -life in sediment can only be estimated as no data are available. As a worst-case assumption, it is similar to the half-life in water

Key value for chemical safety assessment

Half-life in freshwater:
60 d
at the temperature of:
298.15 K
Half-life in freshwater sediment:
60 d
at the temperature of:
298.15 K

Additional information

Biodegradation in water and sediment has not directly been measured, but extrapolation from other data is justified. The values of 60 days (half-life in water and sediment) have to be taken with caution, as this refers to degradation of the propyl side-chains, and the triazine ring. However, more important than degradation by bacteria is hydrolysis which converts TGIC into a triol which lacks all its mutagenicity and other toxicological properties.

With respect to loss of toxicity, a half-life of 6.6 days is probably more significant than the bio-degradation half-life.