Registration Dossier

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

STABILITY

As many other azo metal complexes and azo dyes, the substance does not contain functional groups expected to undergo hydrolysis (e.g. esters, amides, halogen). For this category of compounds in fact, under the environmental conditions of pH and temperature, hydrolysis had been reported as being an insignificant factor in the cleavage of azo compounds [Environment Canada and Health Canada, 2013].

The substance therefore will most likely remain in the water column and due to its characteristics of logKow (-1.75) and water solubility (ca. 40 g/l) the persistence in this phase should be very high. Eventually, the substance will partition first to suspended solids and ultimately sediments where, under the anaerobic conditions of this compartment, it should undergo reductive biodegradation by microbial agents [Brown and Hamburger, 1987].

In addition, due to the very low vaue of vapour pressure and Henry's Law Constant of the substance, partitioning to the air phase should be negligible under environmental conditions.

BIODEGRADATION

A read-across study conducted on the Similar Substance 03 is available, in order to assess the biodegradation potential in water by microorganisms.

In the performed study, a reduction of the test substance was identified by DOC removal by adsorption from the bacterial sludge, quantified at ca. 90 - 100 % after 24 hours. Therefore, the present reduction does not necessarily mean a degradation of the test substance.

Biodegradation was therefore further investigated with the following approaches:

- The assessement of the chemical structure of the substance, according the work of Koichi H. et al. (2000), reported the presence of multiple functional groups linked with no readily biodegradability potential.

- The evaluation of the substance by the EPISuite-BioWin module reported a "not readily biodegradable" prediction.

- An assessment of other structurally similar chemicals (i.e. metal complex azo dyes) belonging to the same category, reported that the substance should not be neither inherently nor readily biodegradable.

BIOACCUMULATION POTENTIAL

The very high molecular weight (> 1000 g/mol) associated with a negative logKow value should limit the bioaccumulation potential in organisms.

References:

Koichi Hiromatsu et al., “Prediction for biodegradability of chemicals by an empirical flowchart”, Chemosphere, 2000.

Used software: EPISuiteTM v. 4.1

CONCLUSIONS

Based on the abovementioned reasons, it can be concluded that the substance could pose a risk of environmental persistence.