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Ecotoxicological information

Toxicity to microorganisms

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Link to relevant study record(s)

Description of key information

The study carried out on Pseudomonas putida, but with methyl salicylate (Sternalski, 1992), has been selected as key study. This study, performed according to the draft of the norm ISO/CD 10712 (1990-10-10), evaluated the inhibitory effect of freshly prepared and aged (120h) methyl salicylate solutions, after 16h incubation in liquid medium. Methyl salicylate is known to slowly hydrolyse in salicylic acid. The decrease in pH of the aged test solutions, together with a slight decrease in toxicity, led to the hypothesis that salicylic acid or a mixture of salicylic acid with methyl salicylate may have been tested in aged solutions. Since the two other reliable studies performed with salicylic acid showed no effect at the highest tested concentrations, the 16h EC10 value (=162 mg/L ) obtained on aged methyl salicylate solutions has been used as a surrogate and worst case data for deriving properly the PNEC STP.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
162 mg/L

Additional information

Two other key studies quoted as Klimisch 2 have been also recorded. The first one (Klecka and Landi, 1985) has been performed according to the OECD 209 guideline : "activated sludge, respiration inhibition test". The IC50-3h obtained was > 1000 mg/L (no NOEC or EC10 was determined).The second study (Henschel et al., 1997) is a 48-h acute toxicity test on the ciliate Tetrahymena pyriformis according to a draft of the OECD guideline (Pauli, 1996). The IC50-48h value obtained was > 100 mg/L (no effect observed at this concentration). Based on the absence of concentration effect value for salicylic acid in several studies, a read-across approach has been applied with methyl salicylate and the study of Sternalski of 1992 for properly determine a concentration inducing an effect and the consecutive PNEC.