Registration Dossier

Ecotoxicological information

Toxicity to terrestrial plants

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

A study of 7 different food crop species, including both dicotyledonous and monocotyledonous plants, determined the lowest 5-day LC50 to be 680 mg/kg/soil dw.  However the short duration of the study makes this value of uncertain reliability for use in assessment.

Key value for chemical safety assessment

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

Additional information

Three studies of short-term toxicity to higher plants are available: unfortunately two monitored seed germination and post-emergence growth over only 5 days, much shorter than the relevant OECD test guideline requires and neither study is considered reliable for use in assessment. (Although Dodd and Addison, 2010 reported 5-day EC50s for parameters of lettuce seedling germination and growth of 81-127 mg MTBE/kg dry soil, this was not supported by a study of An and Lee, 2008 where for 7 different food crop species, including 3 dicotyledonous species listed alongside lettuce in Annex 2 of the OECD 208 guideline, the lowest 5-day LC50 was considerably higher at 680 mg/kg dry soil).

 

The third study examined effects of MTBE exposure on the growth of white corn, Zea mays L (Ismail et al., 2012). This study investigated effects on metabolic activity of white corn exposed to four weekly doses of 50 mL solutions to soil containing 0.5, 1.0 5.0 10, 15% MTBE. No effect on carotenoid levels and catalase enzyme levels only inhibited at highest concentration. Lipid peroxidase levels increased slightly up to 5% and hugely at the two highest doses. However the report gives insufficient information to transcribe the dose information into a dose per unit of soil.