Methyl-1H-benzotriazole

Toxicity to microorganisms

Description of key information

Key values for assessment come from ISO 8192 study with activated sludge exposed to 1H-Benzotriazole. 

Key value for chemical safety assessment

EC50 for microorganisms:

1 060 mg/L

EC10 or NOEC for microorganisms:

394 mg/L

Additional information

In addition to the selected key study according to ISO 8192 several studies with Benzotriazole, Tolyltriazole as well as different commercially available aircraft deicing fluids (ADF) using Microtox test system (Vibrio fischeri) are available (Cancilla, 1997; Cancilla, 2003; Cornell, 2000; Pillard, 2001). The results are summarized below.

Compound	Microtox EC50 (15 min) [mg/L]	Study
5-methylbenzotriazole	4.25 (95% CI 4.18-4.35)	Cancilla, 2003
4-methylbenzotriazole	21 (95% CI 9.0-47)	Pillard, 2001
5-methylbenzotriazole	8.7 (95% CI 8.2-9.2)
1:1 mixture of 4-MBT and 5-MBT	7.3 (95% CI 6.9-7.7)
1H-Benzotriazole	41.65 ± 11.01	Cancilla, 1997
5-methylbenzotriazole	5.91 ± 1.11
different ADFs with tolyltriazole	6-9	Cornell, 2000

 

Based on these observations the three triazoles can be sorted by decreasing toxicity to Vibrio fischeri (Benzotriazole < 4-methylbenzotriazole < 5-methylbenzotriazole) showing a moderate toxicity, in general. However, since the Microtox test is a single-species test only the ISO study has been rated to be more relevant and accordingly selected as key study for the further assessment.

Similar findings to the effect concentrations in the key study with 1H-Benzotriazole has been derived from experimental observations from Gruden et al. (Gruden, 2001) exposing activated sludge with Tolyltriazole. In the toxicity assays a first significant decrease in methane production has been observed at 300 mg/L Tolyltriazole and an inhibition of methanogenic activity of about 50 % at 1000 mg/L Tolyltriazole indicating a likewise toxicity compared to the results of the testing with Benzotriazole.

Cancilla DA et al. (1997) Isolation and characterization of Microtox-active components from aircraft de-icing/anti-icing fluids, Environ Toxicol Chem, 16, 3, 430-434.

Cancilla DA et al. (2003) Studies of the environmental fate and effect of aircraft deicing fluids: Detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimphales Promelas), Environ Toxicol Chem, 22, 1, 134-140.

Gruden CL et al. (2001) Fate and Toxicity of Aircraft Deicing Fluid Additives Through Anaerobic Digestion, Water Environ Res, 73, 1, 72 -79.

Cornell JS et al. (2000) Comparative measures of the toxicity of component chemicals in aircraft deicing fluid, Environ Toxicol Chem, 19, 6, 1465-1472.

Pillard DA et al. (2001) Toxicity of Benzotriazole and Benzotriazole derivatives to three aquatic species, Wat Res, 35, 2, 557-560.