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Ecotoxicological information

Toxicity to terrestrial plants

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Description of key information

critical EC50 = 363 mg a.i./kg soil dw (Lactuca sativa, growth), OECD guideline 208, GLP

Key value for chemical safety assessment

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

Additional information

The effect of DOPA-Glycinate (20% a.i., as manufactured) on the emergence and growth of terrestrial plant seedlings was investigated according to the OECD guideline 208. The following test species were used: Avena sativa (oat), Lactuca sativa (lettuce), Phaseolus aureus (mung bean),Raphanus sativus (radish), Sinapis alba (mustard), and Triticum aestivum (wheat).

The seeds were placed in a natural sandy soil containing the test item at nominal concentrations of 0, 1.64, 4.10, 10.2, 25.6, 64, 160, 400, and 1000 mg a.i./kg dry mass, respectively. The concentration of 1000 mg/kg corresponds to the limit test concentration recommended by OECD-guideline 208. The test item was incorporated into the test soil at the beginning of the experiment, and the effects on seedling emergence and growth were determined 14 days after emergence of 50 % of the control seedlings. Four replicates were prepared for the control and per concentration.

Seedling emergence

There was no concentration dependent effect on seedling emergence of Avena sativa, Phaseolus aureus, Raphanus sativus, and Triticum aestivum up to 1000 mg a.s./kg, the highest concentration tested. Thus, the NOEC for these tested species was found to be ≥ 1000 mg a.i./kg dry soil. The EC50 was found to be > 1000 mg a.i./kg dry soil.

There was a concentration dependent effect on seedling emergence of Lactuca sativa and Sinapis alba starting at 400 mg a.i./kg (NOEC = 160 mg a.i./kg). However, the EC50 for Lactuca sativa was found to be 1062 mg a.i./kg (by extrapolation), and that for Sinapis alba > 1000 mg a.i./kg dry soil.

Growth

There were no statistically significant effects on growth (on a fresh weight per plant basis) of Triticum aestivum up to the highest test concentration (NOEC ≥ 1000 mg a.i./kg, EC50 > 1000 mg a.i./kg). Concentration related inhibition of plant growth was observed in Avena sativa (NOEC = 400 mg a.i./kg), Phaseolus aureus (NOEC ≤ 1.64 mg a.i./kg), Raphanus sativus (NOEC = 10.2 mg a.i./kg), Lactuca sativa (NOEC = 160 mg a.i./kg), and Sinapis alba (NOEC = 400 mg a.i./kg). However, for the first three of these five species, the effects were only moderate, with the growth rate never being inhibited by more than 50 %. Accordingly, the EC50 values for these tested species were found to be > 1000 mg a.i./kg dry soil. For Lactuca sativa and Sinapis alba, EC50 values of 363 mg a.i./kg and 400–1000 mg a.i./kg, respectively, were found.