Registration Dossier

Ecotoxicological information

Toxicity to terrestrial plants

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The 16 day EC50 values in soil based on the effect on emergence and growth were 537, 634 and 1,960 mg a.i./kg dw for S. alba, T. pratense and T. aestivum, respectively, while those in sand were 73, 74 and 141 mg a.i./kg dw, respectively. In sand, toxic effects were seen at lower concentrations than in soil. This was probably due to the lower bioavailability of the test substance in soil caused by stronger adsorption. Furthermore, as the toxicity to terrestrial plants in sand is not representative of the natural environment, the EC50 in natural soil was considered as a reasonable worst case for terrestrial plant species.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:
537 mg/kg soil dw

Additional information

A guideline seedling emergence and seedling growth test was conducted to determine the adverse effects of the read-across substance C12-16 ADBAC on terrestrial plants. Sinapis alba, Trifolium pratense and Triticum aestivum were used. The substance was tested with 40 plants per replicate per dose using 4 replicates for 16 days. The study was performed using natural soil and sand at the following concentrations:

- Natural soil: 0, 476.6, 856.2, 1540.9, 2772.2 and 4990.0 mg/kg

- Sand: 0, 28.8, 55.8, 93.4, 166.8 and 300.5 mg/kg

Analytical determination of the test substance was performed. The test was considered valid on the basis of percent emergence and further growth of the plant in the water control. Effects deviated between quartz sand and natural soil; in sand, toxic effects were seen at lower concentrations than in soil. This was probably due to the lower bioavailability of test substance in soil caused by stronger adsorption. The extraction of the active substance proved that the natural soil had a strong sorbing effect and total recovery was not achieved even when acidified methanol was used as an extraction solvent. That was not the case with quartz sand. The 16 day EC50 values in soil based on the effect on emergence and growth were 537, 634 and 1,960 mg a.i./kg dw for S. alba, T. pratense and T. aestivum, respectively, while those in sand were 73, 74 and 141 mg a.i./kg dw, respectively (Servajean E, 2004).

There were great deviations between quartz sand and natural soil. In sand, toxic effects were seen at lower concentrations than in soil.This was probably due to the lower bioavailability of test substance in soil caused by stronger adsorption. Further, as the toxicity to terrestrial plants in sand is not representative of the natural environment, the EC50 in natural soil can be considered as a reasonable worst case for terrestrial plant species.