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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The toxicity to aquatic algae and cyanobacteria is assessed based on read-across from the close structural analogue Terpinolene to Terpene hydrocarbon alcohols.

Terpinolene's algae toxicity

For Terpinolene, an algae study was performed according to OECD TG 201 and in compliance with GLP criteria. Following a preliminary range-finding test, cultures of freshwater algae (P. subcapitata) were exposed to Terpinolene at nominal concentrations of 0.005, 0.02, 0.05, 0.14, 0.41 and 1.22 mg/L (three replicate flasks per test concentration and six replicates for control) for 72 h, under constant illumination and shaking at a temperature of 21-25°C. Measurements of biomass, growth inhibition and yield were done by determination of cell densities at 24, 48 and 72 h using a counting chamber. The results obtained with positive control (potassium chromate) were in accordance with guideline requirements. The concentrations of the test item (with and without algae) were measured at the start of the study and at the 72-h incubation period. The concentrations were not satisfactorily maintained within ± 20% of the initial concentrations, thus the results were based on the geometric mean of measured exposure concentrations in the abiotic test. The 72h-EC50 and 72h-EC10 values, based on growth rate, were 0.692 and 0.273 mg/L respectively, calculated as geometric mean of measured concentration.

Key value for chemical safety assessment

EC50 for freshwater algae:
0.692 mg/L
EC10 or NOEC for freshwater algae:
0.273 mg/L

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