Indeno[4,3a-b]furan, decahydro-2,2,7,7,8,9,9-heptamethyl-

Toxicity to terrestrial plants

Description of key information

The effect of test item on seedling emergence and seedling growth of six plant species (Brassica napus, Glycine max, Solanum lycopersicum, Cucumis sativus, Avena sativa, Allium cepa) out of six different plant families was studied according to OECD TG 208 and in compliance with GLP criteria. The test item was mixed into the soil before sowing with nominal concentrations of 12.3, 37.0, 111, 333, 1000 mg test item/kg soil dry weight for Brassica napus, Solanum lycopersicum, Avena sativa, Allium cepa and 1000 mg test item/kg soil dry weight for Glycine max and Cucumis sativus. Thirty seeds were tested per treatment group (named concentrations, control and solvent control) and species. The exposure time was 14 or 21 days after 50% emergence in the control depending on the growth of the seedlings. The concentration of the active ingredient in the stock solution was verified analytically. The study was performed in a growth chamber. Exposure conditions were as follows: Mean temperature was 19.4°C (16.1°C to 22.5°C). Mean humidity was 67% (53% to 83%). Photoperiod was 16 hours light / 8 hours dark. Mean light intensity during the day was 244 μE/m2/s (200 to 360 μE/m2/s). The analytical recovery of the test item in the highest concentration was 106% of the mean value. The test item was homogenously distributed in the soil. The EC10 values for test item could be calculated for the fresh weight of Solanum lycopersicum and Allium cepa (32.3 and 129.4 mg test item/kg soil dry weight). For the other species tested, no dose-response curve was calculated due to low effects.

Avena sativa showed a NOEC value based on fresh weight of 37.0 mg test item/kg soil dry weight. This was because of a statistically significantly reduction of 15.6% at 111 mg test item/kg soil dry weight. At 333 mg test item/kg soil dry weight the fresh weight was statistically significantly reduced by 22.6%. This can be explained by the slightly reduced but not statistically significant emergence of only 83%. At 1000 mg test item/kg soil dry weight the fresh weight was statistically significantly reduced by 16.5%. As there is no continuous decrease in fresh weight and emergence is not statistically significantly affected, the effect in Avena sativa is considered to be not treatment related and not biologically relevant as plants are able to compensate reductions on this level without problems. Brassica napus showed a NOEC value based on fresh weight of 111 mg test item/kg soil dry weight. Glycine max and Cucumis sativus were not affected by test item up to 1000 mg test item/kg soil dry weight. The NOEC was ≥ 1000 mg test item/kg soil dry weight for these species. Solanum lycopersicum and Allium cepa showed a NOEC value based on fresh weight of 37.0 and 333 mg test item/kg soil dry weight, respectively.  There was a statistically significant impact of the test item on the emergence of Solanum lycopersicum at 333 and 1000 mg test item/kg dry soil weight (60 and 20%, respectively) and on Allium cepa at 1000 mg test item/kg dry soil weight (60%). The emergence of all other species was not affected. There was no statistically significant mortality for all tested species. Phytotoxic effects observed were slight deformations for Avena sativa at 37.0 and 111 mg test item/kg dry soil weight but not at higher concentrations. Therefore it is considered to be not treatment related. There were no phytotoxic symptoms for all other tested species.

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:

37 mg/kg soil dw