Reaction mass of 4-tert-butylphenyl diphenyl phosphate and bis(4-tert-butylphenyl) phenyl phosphate and triphenyl phosphate

Toxicity to terrestrial plants

Key value for chemical safety assessment

Short-term EC50 or LC50 for terrestrial plants:

181.7 mg/kg soil dw

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

12.3 mg/kg soil dw

Additional information

Only one study is available. However, both short-term (EC-50) and long-term (NOEC) endpoints can be achieved with the OECD 208 study. Indeed, as specified in the OECD 208 guidance: “The test can be conducted in order to determine the dose-response curve, or at a single concentration/rate as a limit test according to the aim of the study. If results from the single concentration/rate test exceed a certain toxicity level (e.g. whether effects greater than x% are observed), a range-finding test is carried out to determine upper and lower limits for toxicity followed by a multiple concentration/rate test to generate a dose-response curve. An appropriate statistical analysis is used to obtain effective concentration ECx or effective application rate ERx (e.g. EC25, ER25, EC50, ER50) for the most sensitive parameter(s) of interest. Also, the no observed effect concentration (NOEC) and lowest observed effect concentration (LOEC) can be calculated in this test.” Therefore, the results were used as such, and values entry for both acute and chronic toxicity were used in the risk assessment.

Planting of seeds into soils with test substance concentrations of up to 1000 mg/kg dry soil resulted in adverse effects on the seedling emergence and/or early growth of all six species tested. The most sensitive endpoint was Height. An EC50 of 181.7 mg/Kg soil was determined for the species Lycopersicon esculentum and a NOEC of 12.3 mg/Kg soil was determined for the species Cucumis sativa.