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Ecotoxicological information

Long-term toxicity to aquatic invertebrates

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Description of key information

Based on a reliable guideline study, the 21-day NOEC was found to be 6.8 and 99.1 μg a.i./L (i.e., equivalent to 0.0068 and 0.099 mg a.i./L) in Southwest well and river water, respectively. The number of days until the first reproduction was similar across all groups within the Southwest well water group and river water group (i.e., 11 and 8- 9 days, respectively) (Valentine and Bishop, 1992).

Key value for chemical safety assessment

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

Additional information

In an OECD 211 study, the effect of the structurally similar C16-C18 and C18 unsat TMAC on the short term (21-day) toxicity and reproduction ofDaphnia magnawas evaluated.Daphnia magnawere exposed to six concentrations of the test substance in a 21-day static-daily renewal test in three different water types (i.e., laboratory blended water, Southwest well water and river water). Analytical determination of the test substance was performed. Measured concentrations (μg/L; values represent the geometric mean of the 0- and 24-h concentration analyses) were: Southwest well water: 1.6, 3.1, 6.8, 14.6, 30.6 and 60.8 μg a.i./LRiver water: 35.7, 53.4, 68.3, 99.1, 122.3 and 309.3 μg a.i./L. The test in blended water was discontinued after 14 days due to inadequate reproduction by control organisms. The mortality was monitored daily and the number of young produced in each beaker was recorded. Test substance concentrations were verified by analysis and represent the geometric mean of the 0 and 24-hour concentration. Under the test conditions, the 21-day NOEC of the test substance was found to be 6.8 and 99.1 μg/L (i.e., equivalent to 0.0068 and 0.099 mg a.i./L) in Southwest well and river water, respectively. The number of days until the first reproduction was similar across all groups within the Southwest well water group and river water group (i.e., 11 days and 8 - 9 days, respectively) (Valentine and Bishop, 1992).