Sodium 4(or 5)-methyl-1H-benzotriazolide

Endpoint summary

Description of key information

The environmental fate and the behaviour of Tolyltriazole was investigated by experimental studies, in silico calculations as well as computational modelling. Besides the conduction of studies in line with the requirements of the Test Methods Regulation and/or OECD guidelines, additional information from the public domain were collected and evaluated.

In total, the substance shows a complex behaviour in the environment. This is based to its high stability regarding most degradation processes as well as the ionisable character of the molecule and its Dipole moment. Depending on the environmental conditions either the non-charged molecule (dominant due to high dissociation constant) or the anionic form pervails which has significant influence on the photochemical and sorption behaviour of the substance.

Tolyltriazole is hydrolytically stable and shows a susceptibility to photolysis in air and water. Only the latter is relevant under environmental conditions due to the low (non) volatility of Tolyltriazole from the water phase. With regard to biodegradation 4-methylbenzotriazole (4-MBTA) seems to be stable under environmental conditions. Only one source indicated a noteworthy removal of 4-MBTA during treatment of wastewater in a STP. On the other hand 5-methylbnezotriazole (5-MBTA) showed a significant higher degradation in several studies under different ambient conditions indicating a certain potential for removal from the environment. This removal rate could be enhanced by adaptation of active sludge communities.

For Tolyltriazole a low potential for bioaccumulation is expected. Under most environmental conditions the non-polar molecule prevails and the potential can be estimated on the partition coefficient. The measured value of log Kow 1.08 is below the trigger value which indicates the need for further investigations. In addition, studies on the bioaccumulation of Tolyltriazole in two Chinese rivers and at different sites accross Europe are line with this assumption. While Yao et al. examined the body burden of approx. 80 fishes (from different species) and calculated a log BAF of 1.47 L/kg, Alvarez-Munoz detected no Tolyltriazole in several species.

In soil and sediment Tolyltriazole is expected to be (highly) mobile. The available information indicate a wide range of distribution and partition coefficients Kd, respectively Koc, depending on the environmental conditions in the laboratory studies and/or field observations. The changes on the behaviour are not only related to a single parameter (e.g. organic carbon content), but is related to several factors which are considered to be connected with the molecule itself (ionic interactions, Dipole moment etc.). Furthermore, Tolyltriazole is non volatile and shows a good solubility in water, so that a majority of the substance is expected to remain in the aqueous phase.

 

Alvarez-Munoz et al (2016), Occurrence of pharmaceuticals and endocrine disrupting compounds in macroalgaes, bivalves, and fish from coastal areas in Europe, Environmental Research 143 (2015) 56–64

Yao et al (2018), Personal care products in wild fish in two main Chinese rivers: Bioaccumulation potential and human health risks. Sci Total Env 621 (2018) 1093–1102