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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

NTO: Acute toxicity to fish (Oncorynchus mykiss), 96 hours: EC50>100 mg/L

Photo-induced degradation products: Acute toxicity to Ceriodaphniadubia. 48 hours: LC50 - 14.5 mg/L (used for environmental risk assessment).

Additional information

Based on ECOSAR v.1 (EPISUITE, 2009), the test substance, NTO, was predicted to have LC50 of 1760.072 mg/L after 96 hours exposure to fish.

Based on the same computer program EPISUITE, the test substance, NTO, was predicted to have LC50 of 222.878 mg/L after 48 hours exposure to Daphnid.

The found LC50 value of 800 mg/L with Ceriodaphnia dubia by Kennedy et al correspond to that value, whereas a study by BAE systems did not allow to conclude on a definite LC50., what however has been calculated to be above 9.5 mg/L. In this study it weas found the pH would shift towards unphysiogically values. Therefore just the NOEC could be derived (2.4 mg/L). The pH depending toxicity fits also well to published data by Haley Mark V., Kuperman Roman G., Checkai Ronald T. They found, the 48h LC50 to Ceriodaphnia dubia is 460 mg/L for pH-adjusted media and 62 mg/L for non-pH-adjusted media.

According to the published data (Haley Mark V., Kuperman Roman G., Checkai Ronald T.: Aquatic Toxicity of 3-Nitro-l,2,4-triazol-5-one ) the 7 day IC50 values for test subtance to Ceriodaphnia dubia was 57 mg/L. The NOEC and LOEC values for test substance to Ceriodaphnia dubia were 34 and 66 mg/L, respectively.

According to the Biotechnology Research Institute of NRC, 2010, the 96h EC50 to aquatic algae was found to be 2323.7 mg/L.

The toxicity to aquatic algae was also examined by AnalyCen Ecotox AS. The72 hours EC50 value for the test substance NTO, Nitrotriazolone was found to be 113 mg/L.

According to Haley Mark V.,Kuperman Roman G., Checkai Ronald T. (Aquatic Toxicity of 3-Nitro-l,2,4-triazol-5-one ), 96h NOEC for the test substance to Scenedesmus capricornutum is 1375 mg/L; 96h LOEC for the test substance to Scenedesmus capricornutum is 2680 mg/L.

The calculation by EPIWIN was showing an EC50 of 1329.272 mg/L after 96 hours exposure to Green Algae.

Although NTO is harmless to aquatic species, adverse effects from photo-induced degradates have been reported by Kennedy et al ( Environ Toxicolo Chem 36, 2017, p2050 -2057) with LC50 14.5 mg/L in a standard 48hr acute toxicity test with Ceriodaphnia dubia. Therefore an environmental risk assessment has been conducted.