Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

General discussion of environmental fate and pathways:

 

Environmental Fate

 

It should be noted that the test substance is not considered as posing a hazard to the aquatic environment.

 

The test substance, Reactive Yellow F01-0555, is a solid under all environmental conditions and is highly soluble in water (> 704.34 g/L). It is expected to have a low volatility (based on a melting point > 400°C). As such, any environmental release will result in virtually all of the substance compartmentalising into water compartments, with little release directly to the atmosphere or compartmentalising to soil/sediment compartments. If directly exposed to soil, the substance may moderately to strongly adsorb to soil particles. The measured log Koc ranged from 2.7 to 4.8.

 

Any potential exposure to the environment is predicted to result in rapid redistribution to water; due to its low volatility, high water solubility and partitioning values it is indicated that the majority of the substance would eventually partition to water rather than to soil and sediment should it be released to the environment. 

 

A Level III fugacity model was conducted in the US EPA EPISUITE ( Mackay et al., 1996a, 1996b; Mackay 1991) which assumes steady-state but not equilibrium conditions. The Level III model in EPI Suite predicts partitioning between air, soil, sediment and water using a combination of default parameters and various input parameters. This model has been used to calculate the theoretical distribution of the highest % component substance between four environmental compartments (air, water, soil, sediment) at steady state in a unit world.

Partitioning is detailed to be:

 

-        Air             6.36e-014%      

-        Water        3.3%

-        Soil            87.9%

-        Sediment  8.76%

 

It is proposed that although the majority of the substance distributes to the soil/sediment compartments within the model, the high solubility in water indicates that the substance is more likely to distribute to water – e. g. soil pore water.

 

Reactive Yellow F01-0555 is considered to be not biodegradable based on read-across studies and a QSAR evaluation, indicating that it is unlikely to achieve a half life of less than 40 days within fresh water attributed to ready biodegradation alone. The substance undergoes hydrolysis at environmentally relevant pH’s (t1/2 = 985 hours (41 days) at pH 7 and 566 hours (23.6 days) at pH 9, at 25°C).Studies on direct phototransformation in water are not available but it is assumed on the basis of chemical structure and nature of use that the substance is not degraded by direct photolysis. It is concluded, therefore, that abiotic processes would contribute significantly to the depletion of the substance within the environment. 

 

Reactive Yellow F01-0555 has a measured log Kow of -3.72. This value indicates that possible bioaccumulation in the food chain is not anticipated. Given the fact that the substance is subject to hydrolysis at biologically relevant pH’s, it is anticipated that bioaccumulation of the substance itself would not occur, as hydrolytic effects in association with metabolic effects would result in removal of the substance.

 

Based on its high water solubility, it can be concluded that it is unlikely that Reactive Yellow F01-0555 could potentially be persistent within the environment. As such, significant contact with organisms via the food chain is not anticipated and can be considered to be minimised. 

 

Finally, Reactive Yellow F01-0555 demonstrates low acute toxicity in mammalian studies therefore in the event of exposure to environmental organisms, effects due to secondary poisoning can be excluded.

 

Reliability.

The studies have all been ranked reliability 1 according to the Klimisch et al system. This ranking was deemed appropriate because the studies were all conducted to GLP in compliance with recognised guidelines.

 

Justification for classification or non classification

 The above results triggered no classification under CLP Regulation (EC No 1272/2008).