Registration Dossier

Ecotoxicological information

Toxicity to soil microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

   
For 44PD, read-across from 7PPD was done. For 7PPD, the toxicity to soil microorganisms was assessed. 7PPD caused a strong and statistically significant reduction in the nitrate formation in soil at concentrations of 333 mg 7PPD/kg soil dry weight and above.
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.

Key value for chemical safety assessment

Long-term EC10 or NOEC for soil microorganisms:
78 mg/kg soil dw

Additional information

According to the OECD Guideline 216 (Soil Microorganisms: Nitrogen Transformation Test), the study was conducted in order to determine possible effects of 7PPD on soil microorganisms through measuring microbial nitrate formation in treated versus untreated soils after 28 days of incubation. A NOEC of 100 mg 7PPD/L and a LOEC of 333 mg 7PPD/L within 28 days related to nitrate formation. After correction for molecular weight, this corresponds to LOEC of 259.8 mg 44PD/kg soil dw and NOEC of 78 mg 44PD/kg soil dw.

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.