N,N'-di-sec-butyl-p-phenylenediamine

Endpoint summary

Description of key information

For 44PD, read-across from 7PPD is done to conclude on the terrestrial toxicity of 44PD. More information on the read-across is provided in the read-across justification document.

In a first study, the long-term toxicity of 7PPD to earthworm (Eisenia fetida) was tested according OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei)) and ISO 11268-2 (Effects of Pollutants on Earthworms. 2. Determination of Effects on Reproduction). During 56 days exposure an NOEC(Reproduction) was determined to be 100 mg 7PPD/kg soil (dw) and the LOEC(Reproduction) as 178 mg 7PPD/kg soil (dw). After correction for molecular weight, this corresponds to an NOEC (reproduction) of 78 mg 44PD/kg soil (dw) and an LOEC (reproduction) of 138.8 mg 44PD/kg soil (dw). 

In a second study, the chronic toxicity of 7PPD to terrestrial plants was tested according to OECD Guideline 208 (Terrestrial Plants Test: Seedling Emergence and Seedling Growth Test). Five to seven different test item concentrations per species were tested against a solvent control (acetone) with each of the six plant species. No significant effect on seedling emergence or mortality was observed for any of the six test species. Effects were observed for shoot length and fresh weight. Shoot length and shoot fresh weight of B. napus seedlings were significantly reduced at concentrations of 15.6 and 62.5 mg 7PPD/kg soil dw, respectively. After correction for molecular weight, this corresponds to 12.2 and 48.8 mg 44PD/kg soil dw. Hence, B. napus was the most sensitive species with regard to shoot length and weight.

In a 3^rdstudy, the toxicity of 7PPD to soil microorganisms was assessed. At test-item concentrations of 10.0 mg 7PPD/kg soil dw and 100 mg 7PPD/kg soil dw nitrate concentration in soil was statistically significantly increased.The LOEC and NOEC were determined to be 333 mg 7PPD/kg soil dw and 100 mg 7PPD/kg soil dw, respectively. After correction for molecular weight, this corresponds to LOEC of 259.8 mg 44PD/kg soil dw and a NOEC of 78 mg 44PD/kg soil dw. Due to the lacking of a dose-response relationship effective concentrations (ECx) could not be calculated. Based on the above results, the test item, 7PPD is considered to have no adverse long-term effects on nitrate formation in soil at concentrations up to and including 100 mg 7PPD/kg soil dry weight. Similarly, it can be concluded that 44PD has no long-term effects on nitrate formation in soil at concentrations up to and including 78 mg 44PD/kg soil dw.