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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
publication
Title:
The ecotoxicity of ionic liquids and traditional organic solvents on microalga Selenastrum capricornutum
Author:
Cho, CW, Jeon, YC, Pham, TPT, Vijayaraghavan, K, Yun, YS
Year:
2008
Bibliographic source:
Ecotoxicology and Environmental Safety. volume 71, pp 166–171

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
not specified
Qualifier:
according to
Guideline:
EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II)
Deviations:
not specified
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): Tetrabutylammonium bromide
- Molecular formula: (CH3CH2CH2CH2)4N(Br)
- Molecular weight: 322.37
- Analytical purity: >99.5%
- Lot/batch No.: Not reported
- Expiration date of the lot/batch: Not reported

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
The test substance was completely miscible with water, forming a homogeneous phase.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The green microalgae used as the model algal strain in this study, Selenastrum capricornutum ATCC-22662, were obtained from the National
Institute Environmental Research, Korea. The algae stock was cultivated in 250 mL Erlenmeyer flasks, containing 200 mL sterilized nitrate-enriched
BBM medium prepared in triple distilled water, to avoid nitrogen limitation during the high-density culture.
The culture flask was agitated on a shaker at 170 rpm, and bubbled with air (1 vvm), without sparger. Light was continuously supplied, with an
average of 30±5 µEm-2 s-1, using warm-white fluorescent tubes (Korea General Electric Co., Korea) located on top of the shaker. All the flasks
were maintained in the shaker incubator at 25±5 °C for 7 days.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h

Test conditions

Hardness:
Not reported
Test temperature:
25 °C
pH:
Not reported
Dissolved oxygen:
Not reported
Nominal and measured concentrations:
Nominal concentrations between 0.1M and 1.26 µM were tested to obtain complete concentration response curves.
Details on test conditions:
Experiments were performed in 250 mL Erlenmeyer flasks, containing 55 mL of sterilized culture medium, inoculated with 5 mL samples of 7-day cultured algae. Solutions of ionic liquids and organic solvents were subsequently added to the test flasks. The ionic liquids and organic solvents tested were completely miscible with water, forming a homogeneous phase. Concentrations of these toxicants were adjusted in the range between 0.1M and 1.26 µM to obtain complete concentration response curves. The flasks then were placed on a shaker incubator at 170 rpm and 25°C, with 24 h light supplied via warm-white fluorescent tubes, with an average illumination of 30±5 µEm-2 s-1. At each determined exposure date, the optical density of the algal biomass was estimated at 438nm using a spectrophotometer (UV mini-1240, Shimadzu, Kyoto, Japan). The dry cell weight, corresponding to the optical density, was determined from the linear relationship; dry cell weight (g/l) = 0.1329x optical density. All experiments were performed in duplicate, but the control experiments were conducted in triplicate.
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
96 h
Dose descriptor:
EC50
Effect conc.:
722 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: Reported as Log10 EC50(µM): 3.35 +/- 0.25

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
The nominal 96h-EC50 value of Tetrabutylammonium bromide to Pseudokirchneriella subcapitata was 722 mg/L.
Executive summary:

The toxicity of Tetrabutylammonium bromide to Pseudokirchneriella subcapitata was determined in accordance with OECD 201 and EPA OPPTS 850.4500 (Tier I and II) guidelines (non-GLP).

Nominal concentrations were not confirmed by analytical measurements. However, since the substance is expected to be stable in an algae study, it can be assumed that the exposure was constant.

The nominal 96h-EC50 value of Tetrabutylammonium bromide was 722 mg/L.