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Ecotoxicological information

Toxicity to terrestrial plants

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Description of key information

 A valid OECD study in Avena sativa, Brassica napus and Vicia sativa is available using the following test concentrations : 62.5, 125, 250, 500 and 1000 mg/kg dry weight. An influence to emergence ws not observed resulting in a NOEC > 1000 mg/kg soil dw for all three species. The influence on growth  was determined to be : NOEC =250 mg/kg soil dw. and the influence on dry weight was NOEC = 62.5 mg/kg soil dw.

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:
423 mg/kg soil dw
Long-term EC10, LC10 or NOEC for terrestrial plants:
62.5 mg/kg soil dw

Additional information

The test substance was mixed via aliquots of a test substance stock solution with natural soil (sandy loam) in the test concentrations 62.5, 125, 250, 500 and 1000 mg/kg dry weight. The water content in the test was about 40 % of the maximal water holding

capacity of the soil. The test system Avena sativa, Brassica napus and Vicia sativa were sowed in the test pots in four replicates per test concentration. The test pots were incubated in a test chamber at 19.6-20.8°C, 65.1-72.5% relative humidity and a day/night

light rhythm of 16/8 hours. The test pots were watered daily and the position of the test pots in the test chamber was randomized daily also.

The number of the emerged seedlings was recorded for the exposure period of 21 days. After 16 days 50 per cent of the seedlings had been emerged in all control assays, all plants were harvested.

The emergence rates of the seed, dry weight, shoot length of the plants at the end of the exposure period were determined as test criteria and given as EC10, EC25, EC50 (effect concentration with confidence limits) and NOEC. Additional morphological changes were evaluated.

An influence to emergence rate caused by the test substance was not observed. However during the course of the exposure period clear effects to the development of the plants of all species were observed. The growth of the plants was effected by increasing

concentrations. The plants of oil seed rap begin to die in the highest test concentration. The plants of oat show with increasing test concentrations a reduced growth and changes at leaves. The clearest effects were observed at oilseed rape and vetch at the parameter formed bio mass expressed as dry weight. The test substance has an influence to the early stage of development all the tested species at the higher test concentrations has an influence to the early stage of development all the tested species at the higher test concentrations.

As laid down in the "Endpoint Spefic Guidance" Chapter R.7.c (Terrestrial Pant Test), data from an OECD 208 test covering the sensitive stage in the life-cycle of a plant can be uses as estimates of chronic toxicity. Therefore, the received data are considered as long term results in the context of the derivation of PNEC soil.