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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The growth rate NOEC and EC50 values based on cell density were 10 and >100 mg/L, respectively (Harlan, 2009: conducted in GLP, following OECD 201). 

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater algae:
10 mg/L

Additional information

One key study has been selected regarding toxicity to algae (Harlan, 2009: conducted in GLP, following OECD 201).

The summary of this study is the following:

In a 72 hour acute toxicity study, the cultures of Pseudokirchneriella subcapitata, (formerly Selenastrum capricornutum), Strain No. 61.81 SAG were exposed to gaiacol at nominal concentrations of 1.0, 3.2, 10, 32 and 100 mg/L under static conditions in accordance with the OECD 201 guideline. The growth rate NOEC and EC50 values based on cell density were 10 and >100 mg/L, respectively. The % growth inhibition in the treated algal culture as compared to the control ranged from -9.4 to 5.4% at 72H.

No abnormalities were noted.

This toxicity study is classified as acceptable and satisfies the guideline requirements for algae toxicity study.

The other data available were all quoted as invalid because of strong deviation to OECD guidelines (durations too short or too long, temperature too high, not agreed species or endpoint tested...), but all led to EC50 > 100 mg/l.

Conclusion: Gaiacol is considered as not harmful to aquatic algae.