2,2'-dimethyl-2,2'-azodipropiononitrile

Endpoint summary

Additional information

The aquatic toxicity of AZDN has been assessed for three trophic level under acute and long-term exposures. The Japanese dataset was not considered as robust enough for characterizing AZDN ecotoxicity as the tests were carried out at concentrations which are far below the water solubility of AZDN (10 mg/L tested versus >300 mg/L water solubility). A new algae test was carried out for strengthening the picture.

The 96-h LC50 of fish Danio rerio is greater than 100 mg/l and less than 500 mg/l. When Oryzias latipes were exposed to varying concentrations of AZDN over 14 days, the NOEC and LC50 of the test substance was found to be not less than 10mg/L.

In the Daphnia magna test, the highest concentration of AZDN tested (367 mg/l) did not show a significant immobilisation following the 48 hours exposure.

The concentrations of test item causing a 50 % reduction in biomass (E_bC₅₀) and in growth rate (E_rC₅₀) for algae within 72 -h were estimated to be 3.9 and 4.5 mg/L respectively. It was possible to determine the No Observable Effect Concentrations (NOEC) which is 1.48 mg/L for both biomass and growth rate.

Long-term test for Daphnia was carried out at concentrations which did not induce mortality.

A Daphnia reproduction study was conducted according to OECD 202 but included reproduction for 21 days rather than 14 days, found that the 21 day 50% lethal concentration (LC50) in parental Daphnia magna was found to be >10 mg/L, whilst the 21 day 50% reproduction inhibition concentration (ErC50) was 7.5 mg/L (95% confidence interval 4.6 -10 mg/L). The maximum no-observed-effect concentration (NOECr) was 2.2 mg/L and the lowest-observed-effect concentration (LOECr) was 4.6 mg/L.

A fish sub-acute toxicity study was conducted at Sumika Technos Corp, Japan to investigate the thresholdsfor lethal and other effects of AZDN. The test type was a flow through study conducted to GLP and according to OECD Guideline 204 and involved exposing the speciesOryzias latipesto the test substance dissolved in the water at nominal concentrations of 1.0, 1.8, 3.2, 5.6 and 10 mg/L over a 14 day period. The fish were observed over the test period for differences in weight, length, behaviour and mortality. At the end of the 14 day exposure period, the no overall effect concentration NOEC was found to be =

10mg/L and the LC50 (the 50% lethal concentration) was estimated to be >10 mg/L. No data are available concerning potential sediment organisms toxicity. Nevertheless based on the expected behaviour of AZDN when released in the environment and its intrinsic properties, one can safely conclude that organisms inhabiting sediments will not be exposed to AZDN. Therefore additional tests on those species are not considered.