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Ecotoxicological information

Toxicity to terrestrial plants

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Description of key information

In a reliable guideline study, the 16 day EC50 values of the read-across substance in soil were 537, 634 and 1,960 mg a.i./kg soil dw for S. alba, T. pratense and T. aestivum, respectively.

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-C16 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 was performed for the test substance. The test was considered as valid on the basis of percent emergence and further growth of the plant in the water control. The side-effects exhibited great deviation 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 the 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 EC50values in soil based on the effect on emergence and growth were 537, 634 and 1,960 mg a.i./kgdw of soil for S. alba, T. pratenseand T. aestivum, respectively, while those in sand were 73, 74 and 141 mg a.i./kg dw of sand, 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.