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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:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1982-08-06 To 1982-08-20
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1982
Report Date:
1982
Reference Type:
publication
Title:
Unnamed
Year:
1986

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Payne AG, Hall RH, 1979, in Aquatic Toxicology, ASTM, STP 667, pp. 171-180; and US EPA, 1978, The Selenastrum capricornutum Printz algal assay. Deviations, reliability, and validity evaluated using the subsequent OECD 201 (2006) test guideline.
Deviations:
no
GLP compliance:
no
Remarks:
(study conducted prior to GLP)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material: Linear Alkylbenzene Sulfonate; (C11.9 LAS); LAS Sodium Salt; (X0235.01)
- Substance type: Pure active substance
- Physical state: A white paste
- Stability under test conditions: Not available
- Storage condition of test material: Not available
Specific details on test material used for the study:
Material was tested as 30.4% active (30.4% LAS, 51.9% water and 17.7% inert)

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A primary stock solution of X0235.01 was prepared by adding a weighed amount of test material to algal growth medium, and other stock solutions were prepared by serial dilution. A growth medium control was conducted concurrently and contained no test material. All test concentrations were prepared by pipeting 1.0 milliliter (ml) of the appropriate stock solution to each test flask.
- Controls: AAP medium
- Evidence of undissolved material: No

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Green algae
- Strain: Not available
- Source: University of Texas at Austin, Austin, Texas
- Age of inoculum (at test initiation): Not available
- Method of cultivation: Not available

ACCLIMATION
- Acclimation period: Not available
- Culturing media and conditions: Same as test
- Any deformed or abnormal cells observed: Not available

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
120 h
Remarks on exposure duration:
72 hour results reported here
Post exposure observation period:
Yes (9 days)

Test conditions

Hardness:
Not available
Test temperature:
Static bioassays were conducted at 24 C (+/-1) degree C in water bath
pH:
Not available
Dissolved oxygen:
Not available
Nominal and measured concentrations:
Nominal laboratory exposure concentrations based on active ingredient were 0, 16, 32, 63, 125, 250, 500, and 1,000 mg/L.
No analytical measurements of test concentrations were taken.

Details on test conditions:
TEST SYSTEM
- Test vessel:
- Open / closed: Not available
- Material: 125-ml flasks with 50 ml solution
- Aeration: No
- Initial cells density: 2x10(4) cells/ml
- Control end cells density: Test 1: 206x10(4);
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: Yes, AAP nutrient medium

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: AAP media prepared with deionized water
- Total organic carbon: Not available
- Particulate matter: Not available
- Metals: Not available
- Pesticides: Not available
- Chlorine: Not available
- Alkalinity: Not available
- Ca/mg ratio: Not available
- Conductivity: Not available
- Culture medium different from test medium: No
- Intervals of water quality measurement: Not available

OTHER TEST CONDITIONS
- Sterile test conditions: Not available
- Adjustment of pH: No
- Photoperiod: Not available
- Light intensity and quality: Approximately 2,000 lux

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: Hemacytometer
- Cell counts were made on day 0,2,3,4,5.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2 - Range finding study: no
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
other: ECr50
Effect conc.:
235 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Remarks on result:
other: 72-hr ECr50: 235 (34.6 - 965) mg/L
Remarks:
Data is present within the study report to allow for 72 hr EC10 and EC50 endpoint calculations with the emphasis on growth rate (as recommended by OECD 201). The 72 hr modernized endpoints are reported within this summary.
Duration:
96 h
Dose descriptor:
other: ECr10
Effect conc.:
13.1 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Remarks on result:
other: 96-hr ECr10: 13.1 (0 - 99) mg/L
Remarks:
Data is present within the study report to allow for 72 hr EC10 and EC50 endpoint calculations with the emphasis on growth rate (as recommended by OECD 201). The 72 hr modernized endpoints are reported within this summary.
Details on results:
- Exponential growth in the control: Yes, 103X at 72 hrs
- Observation of abnormalities: In all test concentrations >=1.0 mg/L, the algal cells were abnormally large and malformed. Because of this observation, algae previously exposed to 1000 mg/L were tested for their ability to recover. Their growth was similar to the growth of the control during a 9-day recovery period in test material-free medium, and the algal cells had returned to normal appearance.
- Any stimulation of growth found in any treatment:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Any other information on results incl. tables

Effect of LAS on Selenastrum capricornutum: Cell Counts at 72 hr (study # 29101)

Nominal Conc (mg/L) Algal cell counts (x104/ml) Growth Rate % Inhibition
0 318 (25) 1.5449  
16 136 (37) 1.4586 5.59
32 138 (13) 1.2869 16.7
63 177 (34) 1.1447 25.91
125 45 (19) 0.8141 47.3
250 28 (4) 0.7504 51.43
500 24 (5) 0.7324 52.59
1000 5 (2) 0.3054 80.23

C10-13 LAS(X0235.01).

Numbers in parenthesis are standard deviation.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In a 72 hour algae growth inhibition test, the EC10 and EC50 of LAS to Selenastrum capricornutum was 13.1 (0 – 99) and 235 (34.6 – 965) and mg/L, consecutively.

Executive summary:

In a 72 hour algal growth inhibition test, the green alga Selenastrum capricornutum was exposed to Linear Alkylbenzene Sulfonate (C11.9 LAS) in accordance with OECD 201. The nominal test concentrations were (test 1) control, 16, 32, 63, 125, 250, 500, and 1,000 mg a.i./L,.

The 72 hour EC10 and EC50, based on growth rate, are 13.1 (099) and 235 (34.6965) mg/L, consecutively.

This algal growth inhibition test satisfies the guideline requirements of the OECD 201 guideline.

 

This study was conducted in accordance with USEPA OPPTS 850.5400. However data is present within the study report to allow for 72 hr EC10 and EC50 endpoint calculations with the emphasis on growth rate (as recommended by OECD 201). The 72 hr modernized endpoints are reported within this summary. These endpoints appear less conservative to those previously reported (96 hr endpoints based on cell count) due to the use of continuous growth rate versus cell count.