Benzenesulfonic acid, 4-C20-24 (even numbered) sec-alkyl derivs., sodium salts

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:

toxicity to aquatic plants other than algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From July, 1978 to November, 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well-documented publication/study report which meets basic scientific principles.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1981

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 221 (Lemna sp. Growth Inhibition Test)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

no

Remarks:

pre-dates GLPs

Test material

Test material information

Constituent 1

Reference substance name:

Benzenesulfonic acid, C10-13-alkyl derivs., sodium salts

EC Number:

270-115-0

EC Name:

Benzenesulfonic acid, C10-13-alkyl derivs., sodium salts

Cas Number:

68411-30-3

IUPAC Name:

sodium 4-undecylbenzenesulfonate

Test material form:

solid

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Not reported

Test solutions

Vehicle:

no

Details on test solutions:

Not reported

Test organisms

Test organisms (species):

Lemna minor

Details on test organisms:

TEST ORGANISM
- Common name: Duckweed
- Strain: Not reported
- Source: The test species was originally collected near Boca Raton, Florida, and has been in continuous culture at the EPA Environmental Research Laboratory, Duluth, Minn., since 1971.
- Age of inoculum (at test initiation): Not reported
- Method of cultivation: Test species stocks were maintained in X0.01 Hutner's solution in a flow through system

ACCLIMATION
- Acclimation period: Not reported
- Culturing media and conditions (same as test or not): Not reported
- Any deformed or abnormal cells observed: Not reported

Study design

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Post exposure observation period:

None

Test conditions

Hardness:

120-130 (as CaCO3 ) mg/L

Test temperature:

21-23 °C

pH:

7.2-7.6

Dissolved oxygen:

8.5 mg/L

Nominal and measured concentrations:

Nominal concentration: Not specified in the study report. All results are based on measured active ingredient. Details of analytical results are not provided in the study report. The test concentrations, based on measured active components, were: 0, 2.1, 3.8, 8, 17 and 34 mg/L.

Details on test conditions:

TEST SYSTEM
- Incubation chamber used: Incubators were not used. However, the test chambers were placed in environmental control housing with a removable front cover for servicing.
- Test vessel: Pyrex glass test chambers
- Type: Open
- Material: All glass test chambers were separated into four individual compartments, each measuring 1.5 x 10.8 x 6.8 cm. Water volume in each compartment was regulated to approx. 400 mL
- Type of cover: Not reported
- Aeration: No (flow-through test)
- Agitation: No
- Type of flow-through: Proportional diluter
- Renewal rate of test solution: Water flow into the diluter was 1.5 L every 16 minutes, which was mixed with 6 mL nutrient stock to give the final concentration of 0.01X Hutner's solution in the test chambers. The flow rate through the individual test chambers was approximately 14 replacement volumes/day.
- Control end cells density: Not reported
- No. of colonies per vessel: Seven (two-frond, root-excised duckweed colonies)
- No. of fronds per colony: Two
- No. of vessels per concentration (replicates): Four
- No. of vessels per negative control (replicates): Four

GROWTH MEDIUM
- Standard medium used: No
- Detailed composition if non-standard medium was used: Nutrient stock solution used was X2.5 Hutner's solution which was mixed with dilution water to give the final concentration of X0.01 in the test chambers. Detailed composition of growth medium is not reported in the study.

SEDIMENT USED: Sediment was not used as the test species is a floating plant

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The dilution water was carbon- and reverse osmosis filtered well water, with added nutrients.
- Total organic carbon: Not reported
- Particulate matter: Not reported
- Metals (mg/L): Mercury = <0.005, Cadmium = <0.005, Zinc = <0.001, Lead = <0.005, Copper = <0.001, Iron = <0.05, Sodium = 11.6, Nickel = <0.033
- Pesticides (mg/L): Chlorinated insecticides= <0.00005, Organophosphate insecticides = <0.0005
- Nitrite: <0.05 mg/L
- Nitrate: <0.05 mg/L
- Chlorine: Not reported
- Alkalinity: Not reported
- Ca/mg ratio: Not reported
- Conductivity: Not reported
- Culture medium different from test medium: No
- Intervals of water quality measurement: Not reported

OTHER TEST CONDITIONS
- Sterile test conditions: Not reported
- Adjustment of pH: Not reported
- Photoperiod: Continuous illumination
- Light intensity and quality: 3875 lux (360 foot candles) fluorescent lights

EFFECT PARAMETERS MEASURED
- Determination of frond number: Number of fronds in each replicate chamber was recorded once every 24 h for 7 d. Every frond visibly projecting beyond the edge of the parent frond was counted manually.
- Determination of biomass: Dry weights were determined at the end of exposure period.
- Determination of frond area: Not determined
- Other: The root lengths were determined at the end of the exposure period. Where possible, 15 to 20 roots from each replicate weremeasured to the nearest 0.5 cm and the ten largest values were selected for statistical analysis. All plant material from each replicate was placed in a tared aluminum dish and dried at 103°C for 3 h. Since the growth rates stabilized by the Day 4, only frond count data from Days 4 through 7, and Day 7 root length and dry weight data were used for statistical analysis. From the frond count data, two other parameters growth rate and doubling time were computed or Day 4 through 7.

NEGATIVE CONTROL PERFORMED: Yes (received only carbon and reverse osmosis filtered well water)

RANGE-FINDING STUDY: No

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

3.6 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Remarks on result:

other: 2.9-4.3

Effect concentrations 2

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

4.9 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

other: root length

Remarks on result:

other: 0-12.6

Effect concentrations 3

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

4.8 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: 4.4-5.2

Effect concentrations 4

Duration:

7 d

Dose descriptor:

EC10

Effect conc.:

0.21 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

frond number

Remarks on result:

other: 0.16-0.38

Effect concentrations 5

Duration:

7 d

Dose descriptor:

EC20

Effect conc.:

0.53 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

frond number

Remarks on result:

other: 0.37-0.75

Effect concentrations 6

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

2.29 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

act. ingr.

Basis for effect:

frond number

Remarks on result:

other: 1.9-2.7

Details on results:

- Any visual signs of phytotoxicity (abnormalities): Not reported
- Decrease in frond size: Not reported
- Necrosis / chlorosis: Not reported
- Sinking of fronds: Not reported
- Other: Frond count decreased dose dependently from Day 4 with increase in exposure concentration
- Any stimulation of growth found in any treatment: Not reported
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Not reported
- Effect concentrations exceeding solubility of substance in test medium: No

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

Endpoint values for frond count were derived using SAS v. 9.1.3. The frond count data were fit to an empirical non-linear model. The growth rate data were fit to empirical models derived directly from the frond count model. Root length and dry weight were fit to the same exponential model given by growth rate. See Appendix to study report for more details on statistical evaluations.

Any other information on results incl. tables

None

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 7d EC10 of C12 LABS Na (linear alkylbenzene sulfonate) to Lemna minor was 0.21 mg/L, based on frond count in a flow through test. The result is based on measured concentration.

Executive summary:

A growth inhibition test to Lemna minor (duckweed), following OECD 221 guideline, was conducted on C11.8 LABS Na (linear alkylbenzene sulfonate). Endpoints included frond count, dry weight, growth rate, and root length after 7 d exposure period in a flow through study. The test concentrations were 0, 2.1, 3.8, 8, 17 and 34 mg/L (measured). There were 4 replicates at each test concentration.

The EC10 value, based on frond number, was 0.21 mg/L. The EC50 value, also based on frond number, was 2.30 mg/L.

This growth inhibition test is classified as acceptable, and satisfies the guideline requirements for the OECD 221.