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Toxicity to aquatic algae and cyanobacteria

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toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
according to guideline
ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
Details on test solutions:
The test substance w as insoluble in water. Water accommodated fractions (WAF) were prepared individually by stirring appropriate amounts of the test substance in growth medium (according to ISO 14442:2006). The solutions w ere stirred with a spin-bar for 22 hours w ith a speed which formed a vortex one-third of the depth of the fluid content followed by standstill for about 1.5 hour.
Test organisms (species):
Skeletonema costatum
Details on test organisms:
- The strain of Skeletonema costatum (NIVA-BAC 1) used in this test was originally isolated from the Oslo fiord (1962).
- The culture was bought from Norsk Institut for Vannforskning (NIVA) in Oslo 25.09.2009.
- In the laboratory the algae were held at 15 +/- 2 °C under continuous light from fluorescent tubes of universal natural white type.
- The pre-culture used in this test was started 25.09.2009 and incubated on an orbital shaker.
- Sub-cultures are started twice to three times a week by transferring amounts of the growing culture to approx. 50 mL of fresh growth medium.
- The inoculum used in the present test was last fansferred on 06.11.2009.
- At the start of the test on 10.11.2009 the cell density of the inoculum w as 342000 cells/mL.
- The cell number was determined by microscope counting using a Palmer-Maloney counting slide.
Test type:
Water media type:
Limit test:
Total exposure duration:
72 h
Test temperature:
19.1-20.9 °C
34.4 per mill
Nominal and measured concentrations:
- test substance concentrations nominal :3.0, 10.0, 31.9, 100 and 320 mg/L
Details on test conditions:
- Test concentrations of 50 mL were added to 100 mL flat-bottomed flasks
- 3 replicates for each concenfration and six replicates for the blank (gowth medium with no added chemicals)
- The amount of inoculum added to each test concentration was 300 µl.

- Natural seawater from an unpolluted site at about 80 m depths in Byfjord was collected from a tap.
- The seawater was filtered through a GF/C filter and briefly heated to about 75 °C prior to use.
- The Seawater was enriched with nutrients accordimg to ISO 110253.

- The test was run for 72 +/- 2 hours and sub-samples of 5 ml were taken from the test flasks each day for growth measurements.
- Algal growth was measured by fluorescence on a Turner Designs, Model 10 fluorimeter.( Wavelengths: excitation 430 nm, emission > 665 nm).
- pH measurements w ere conducted at start (day 0) and at the end of the test (day 3) with a Radiometer PHM 210 instrument.
Reference substance (positive control):
72 h
Dose descriptor:
Effect conc.:
38.7 mg/L
Nominal / measured:
Conc. based on:
other: WAF (Water accommodated fraction)
72 h
Dose descriptor:
Effect conc.:
3 mg/L
Nominal / measured:
Conc. based on:
other: WAF
Details on results:
A significant growth-stimulating effect was observed at the test concentration 3.0 mg/L WAF, which means that this concentration gave responses differing from the blank by showing a higher growth rate. This is why NOEC is stated as; the highest test concentration without significant growth inhibition.

Description of key information

Sebacic acid is acutely harmful to aquatic algae.

Key value for chemical safety assessment

Additional information

The acute toxicity of sebacic acid on algae was studied in a marine growth inhibition test with Skeletonema costatum, in accordance with ISO 10253 [BASF SE, 2009]. The interpolated 72 hours EL50 is 38.7 mg/L WAF (water accommodated fraction) and the 72 hours NOEC is stated with 3 mg/L WAF.