Naphthalene

Toxicity to aquatic algae and cyanobacteria

Description of key information

The test results available for algae appear to show short-term effects at lower levels than the results from longer term tests. Thus growth was affected at 400 μg/l over three days and a 4-hour EC50 for CO2 assimilation of 2.9 mg/l was determined, whereas 10-day and 14-day tests had LC50s for biomass production of 33 and 25 mg/l. This may indicate acclimation to the chemical with time. 

Key value for chemical safety assessment

EC50 for freshwater algae:

2.96 mg/L

EC50 for marine water algae:

410 µg/L

Additional information

The test results available for algae appear to show short-term effects at lower levels than the results from longer term tests. Thus growth was affected at 400 μg/l over three days (Østgaard et al., 1984) and a 4-hour EC50 for CO2 assimilation of 2.9 mg/l was determined (Milleman et al., 1984), whereas 10-day and 14-day tests had LC50s for biomass production of 33 and 25 mg/l (Kauss and Hutchinson, 1975 and Gaur, 1988, respectively). This may indicate acclimation to the chemical with time.