Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs., calcium salts

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Duplicate samples were taken from each loading rate and the control at the start and at 48-hours. For the 48-hour stability samples, the contents of the respective replicates were pooled.
All samples were stored frozen prior to analysis.

Vehicle:

no

Details on test solutions:

- Method: water accommodated fractions (WAFs)
Nominal amounts of test item (5.0, 16, 50, 160 and 500 mg) were each separately added to the surface of 5 liters of test water to give the 1.0, 3.2, 10, 32 and 100 mg/L loading rates respectively. After the addition of the test item, the test water was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 23 hours and the mixtures allowed to stand for 1 hour. Visual observations made on the WAFs indicated that a significant amount of dispersed test item was present in the water column and hence it was considered justifiable to remove the WAFs by filtering through a glass wool plug (2-4 cm in length). A wide bore glass tube, covered at one end with Nescofilm was submerged into the vessel, sealed end down, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal. A glass wool plug was inserted into the opposite end of the tubing and the WAF removed by mid-depth siphoning (the first 75-100 mL discarded) to give the 1.0, 3.2, 10, 32 and 100 mg/L loading rate WAFs. Microscopic observations of the WAFs were performed after filtering and showed that filtration had removed all of the dispersed test item.
- Controls: test water (ISO 6341)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flee
- Source: in-house culture
- Age at study initiation: < 24 h

Adult daphnia were maintained in 150 mL glass beakers containing Elendt M7 medium in a temperature controlled room at approximately 20 °C. The lighting cycle was controlled to give a 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods.

Cultures were fed daily with a mixture of algal suspension (Desmodesmus subspicatus) and Tetramin® flake food suspension.
Culture conditions ensured that reproduction was by parthenogenesis.

Gravid adults were isolated the day before initiation of the test, such that the young daphnids produced overnight were less than 24 hours old. These young were removed from the cultures and used for testing.
The diet and diluent water are considered not to contain any contaminant that would affect the integrity or outcome of the study.

- Feeding during test: none

ACCLIMATION
- Acclimation period: not relevant, conditions were comparable for maintenance and testing

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.5 mM (250 mg CaCO3/L)

Test temperature:

22 °C

pH:

7.3 - 7.6

Dissolved oxygen:

8.5 - 8.9 mg O2/L

Nominal and measured concentrations:

nominal loading rates: 3.2, 10, 32, and 100 mg/L as WAF
measured test concentrations:
test start (0 h): 2.62 – 20.3 mg/L
test end (48 h): 96 – 103 % of the initially measured values
The samples of the loading rate 1.0 was not analyzed since this loading rate was below the 48-hour NOELR determined in this test and was therefore not relevant for the interpretation of the biological results.
The biological results are based on the loading rate of the test item.

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass jars containing approximately 200 mL test medium, covered
- Aeration: none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: 40 mL/animal

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water (ISO medium) according to the guidelines.
- Ca/Mg ratio: 4:1
- Culture medium different from test medium: yes (daphnids were cultured in Elendt M7 Medium)
- Intervals of water quality measurement: water temperature was recorded daily, oxygen concentration and pH were measured at the start and at the end of the test.

OTHER TEST CONDITIONS
- Adjustment of pH:no
- Photoperiod: photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods
- Lighting: 200 - 1200 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Daphnids were inspected for immobility and sub-lethal effects after 24 and 48 hours of exposure.

RANGE-FINDING STUDY
- Test concentrations: nominal loading rates of 1, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: No immobilization was observed at 1.0 mg/L loading rate WAF, however, immobilization was observed at 10 and 100 mg/L loading rate WAF (40 % and 100 %, respectively)

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

5.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

nominal loading rates

Basis for effect:

mobility

Remarks on result:

other:

Remarks:

95% confidence interval: 4.8 - 6.8 mg/L

Key result

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

nominal loading rates

Basis for effect:

other:

Remarks:

mobility and sub-lethal effects

Details on results:

Behavioural abnormalities:
- Other biological observations: none
- Mortality of control: yes, one single immobilized daphnia was observed
- Other adverse effects control: none
- Abnormal responses: none

All test media were clear solutions throughout the test period.

For details see attached document "Table - Effects on Daphnids.pdf"

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels:
- 48-hour EC50: 0.75 mg/L with 95% confidence limits of 0.69 - 0.82 mg/L (within the range 0.6 – 2.1 mg/L as given by the guidelines)

Reported statistics and error estimates:

Statistical analyses were performed using the ToxRat Professional computer software package (ToxRat® Solutions GmbH, Version 2.10.06).
The EL50 values and associated confidence limits at 24 and 48 hours were calculated by Probit analysis using Linear Maximum-Likelihood regression. The Lowest Observed Effect Loading Rate and the No Observed Effect Loading Rate at 24 and 48 hours were calculated using the Fisher's Exact Binomial Test with Bonferroni correction.

Validity criteria fulfilled:

yes

Remarks:

In the control, not more that 10 % of the daphnids have been immobilised or showed other sub-lethal effects; the dissolved oxygen concentration at the end of the test was > 3 mg/l in all vessels.

Description of key information

effect value for Daphnia magna, based on loading rates (OECD 202, EU C.2):

48-h EL50: 5.7 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

5.7 mg/L