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Ecotoxicological information

Toxicity to terrestrial plants

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Description of key information

Key study, guideline EPA OPP 122-1 (Seed Germination/Root Elongation Toxicity Test), (Cross, 1993):

7d-EC25 (Lactuva sativa) = 0.28 lb/acre (based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

Key study, EPA OPP 122-1 (Terrestrial Plant Toxicity Tier I (vegetative vigor)) and  EPA OPP 123-1 (Vegetative Vigor Tier II), (Cross, 1993):

NOEL (monocots) = 0.03 – 1.0 lb/acre (based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

NOEL (dicots) = 0.016 – 2 lb/acre (based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

Lowest EC25 : 18d-EC25 (Helianthus annuus) = 0.026 lb/acre (based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

Lowest EC50 : 18d-EC50 (Helianthus annuus) = 0.12 lb/acre (based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

Supporting study, guideline EPA OPPTS 850.4225 (Seedling Emergence Tier II), (Porch,1998), GLP:

10d-NOEC = 0.1 lb/acre (for cabbage and lettuce seedlings, based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

10d-NOEC = 0.25 lb/acre (for carrot, onion, rye grass, and tomato seedlings, based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

10d-NOEC = 0.63 lb/acre (for bean, corn, soybean and wheat seedlings, based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

The lowest EC25 were obtained for cabbage (Brassica oleracera) and lettuce (Lactuva sativa):

14d-EC25 = 0.21 lb/acre (for cabbage, based on fresh weight data and based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

14d-EC25 = 0.23 lb/acre (for lettuce, based on fresh weight data and based on nominal concentrations further to analytical confirmation that concentrations remained within + or - 20% of the nominals)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for terrestrial plants:
0.024 mg/kg soil dw

Additional information

Valid chronic studies based on international guidelines are available for terrestrial plants and soil microorganisms.

Sunflower, cabbage and lettuce appeared to be the most sensitive species with :

18d-EC25 (Helianthus annuus) = 0.026 lb/acre (sunflower vegetative vigor), 14d-EC25 (Brassica oleracera) = 0.21 lb/acre (cabbage fresh weight, seeling emergence test) and 14d-EC25 (Lactuva sativa) = 0.23 lb/acre (lettuce fresh weight, seedling emergence test). In the seed germination test, lettuce appeared again as the most sensitive species with : 7d-EC25 (Lactuva sativa) = 0.28 lb/acre.

For the lowest EC25 : 0.026 lb/acre, converted to mg/kg of soil dw : 0.026 * 1.49 = 0.039 mg / kg soil dw

For the lowest NOEL : 0.016 lb/acre, converted to mg/kg of soil dw : 0.016 * 1.49 = 0.024 mg / kg soil dw