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 Blue 19, is a solid under all environmental conditions and is highly soluble in water (>220 g/L). It has a low volatility (2.4E-5 Pa at 20°C) and a low affinity for soil / sediment (log Koc 2.5). As such, any environmental release will result in virtually all of the substance compartmentalising into water compartments, with little release directly to atmosphere or compartmentalising to soil/sediment compartments.

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 indicates 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 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           2.05E-009%

-Water     17.1%

-Soil          82.8%

-Sediment 0.0985%

It is proposed that although the majority of the substance distributes to the soil 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 Blue 19 displays slow biodegradability based on a Standversuch with a liquid preparation of Reactive Blue 19 (>70% biodegradability after 27 days), a read-across study with the parabase form Reactive blue 19:1 (30-40% biodegradability after 28 days) and a QSAR evaluation (Does Not Biodegrade Fast (BIOWIN v4.10)), however, the substance showed hydrolysis at environmentally relevant pH’s (pH 7 half-life 9.8 days at 25°C; pH 9 half-life 0.1 days at 25°C), indicating the potential for significant removal by hydrolysis. As such, degradation is anticipated predominantly via this route. Due to the effects of hydrolysis at environmentally relevant pH’s adding to the slow biodegradation, it is proposed that the substance cannot be considered to have a half-life in fresh water higher than 40 days. 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.

Reactive Blue 19 has a measured log Kow of -7.2. 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, low partition coefficient and fairly rapid hydrolysis rate at environmentally relevant pH’s, it can be concluded that it is unlikely that Reactive Blue 19 could potentially be persistent within the environment. Abiotic effects will result in eventual removal from the environment and hence significant contact with the organisms in the food chain can be considered to be minimised.

Adsorption to soil is deemed to be low, based on the log Koc and the very low partition coefficient value and high water solubility. Such a low potential indicates that the substance is unlikely to bind tightly to soils and sediments and instead partition almost exclusively to water. As such, significant exposure related effects to sediment and soil dwelling organisms are considered to be negligible.

Finally, Reactive Blue 19 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 or 2 according to the Klimish et al system. This ranking was deemed appropriate because the studies were conducted in compliance with recognised guidelines and/or according to GLP.

Justification for classification or non classification

The above results triggered no classification under the Dangerous Substance Directive (67/548/EEC) and the CLP Regulation (EC No 1272/2008).