Tris(2,4-ditert-butylphenyl) phosphite

Toxicity to terrestrial plants

Description of key information

The toxicity to terrestrial plants was determined in a study according to OECD guideline No 208 and in compliance with GLP criteria (BASF, 2016). In this study, 6 plant species were examined for visual phytotoxic effects and mortality. Oats, onions and lettuce were exposed to test substance concentrations of 0 (control), 12.3, 37.0, 111, 333 and 1000 mg/kg d.w. No test substance analysis was performed. Sugar beet and soybean were exposed to test substance concentrations of 0 (control) and 1000 mg/kg d.w. and finally rape was exposed to test substance concentrations of 0 (control), 500 and 1000 mg/kg d.w. All test concentrations were based on a preliminary range-finding test. The test item was incorporated into the soil in which the seeds were sown afterwards. The test containers were bottom watered with nutrient solution as needed. Potential toxic effects of the test item were assessed on day 7, 14 and 21 by visual observations (number of emerged seedlings and phytotoxic effects) and at test end by shoot height and shoot fresh weight determination. For onion the rate of emergence of the control plants reached >50 % within 14 days and therefore, the test with onion was prolonged until 28 days. No significant test item related phytotoxic effects and mortality occurred during the test period for all tested plant species. No EC50 values could therefore be determined. The NOEC was determined at ≥1000 mg/kg d.w. for shoot height, shoot fresh weight and number of emerged seedlings in all 6 plant species tested. Although the test does not cover chronic effects or effects on reproduction, it covers a sensitive stage in the life-cycle of a plant and data obtained from this study are generally used as estimate of chronic toxicity. Therefore, a 21 -d NOEC of 1000 mg/kg d.w. is used for assessment.

Key value for chemical safety assessment

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

1 000 mg/kg soil dw