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Ecotoxicological information

Long-term toxicity to aquatic invertebrates

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Description of key information

A 21-day static-renewal reproduction study was conducted and endpoints included adult daphnid survival, reproduction (total young produced per surviving adult female), and growth (length and weight of surviving adults). 
• The NOEC for survival, and reproduction was 2.44 mg/L and the LOEC and MATC values were 5.01 and 3.50 mg/L, respectively.
• The NOEC , LOEC and MATC for length and weight at study termination were >5.01 mg/L.
• The 21-day EC50 values for survival and reproduction were 4.33 and 3.86 mg/L, respectively.
• Since no morality occurred in the controls or any treatment level through the first 48 hours of the study conduct, the 48-hr EC50 was >21.9 mg/L

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater invertebrates:
2.44 mg/L

Additional information

The chronic toxicity of nitroethane to the freshwater daphnid, Daphnia magna was evaluated. A 21-day static-renewal reproduction study was conducted and endpoints included adult daphnid survival, reproduction (total young produced per surviving adult female), and growth (length and weight of surviving adults).

The study was conducted with ten daphnids (one individual per replicate with ten replicates per dose level) exposed to nominal concentrations of 0 (water control), 1.5, 3.0, 6.0, 12.0 and 24.0 mg nitroethane/L. Test solutions were renewed at least three time weekly ( Monday, Wednesday, and Friday) through-out the 21-day exposure. Daily observations were made and the number of surviving daphnids recorded. Reproduction was evaluated by counting and removing neonates on test solution renewal days (M, W, and F). At test termination (day 21), lengths and dry weights of all surviving adult daphnids were measured and recorded.

The samples were analyzed for nitroethane by gas chromatography/mass spectrometry (GC/MS). The resulting mean measured test concentrations were 1.26, 2.44, 5.01, 10.3 and 21.9 mg/L.

The chronic effect concentrations for nitroethane with Daphnia magna were statistically and/or empirically determined using mean measured test concentrations. The resulting values are listed below:

• The NOEC for survival, and reproduction was 2.44 mg/L and the LOEC and MATC values were 5.01 and 3.50 mg/L, respectively.

• The NOEC , LOEC and MATC for length and weight at study termination were >5.01 mg/L.

• The 21-day EC50 values for survival and reproduction were 4.33 and 3.86 mg/L, respectively.

• Since no morality occurred in the controls or any treatment level through the first 48 hours of the study conduct, the 48-hr EC50 was >21.9 mg/L.