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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
Protocol was designed to meet the known requirements of Annex V to Commission Directive 92/69/EEC: C.2. Acute Toxicity for Daphnia and the OECD Guideline for Testing of Chemicals No. 202, Part 1, Daphnia sp., Acute Immobilisation Test
GLP compliance:
yes
Remarks:
QA statement included in study report

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
White powder
Specific details on test material used for the study:
No expiry date specified.

Sampling and analysis

Analytical monitoring:
not specified
Details on sampling:
The pH, temperature and concentration of dissolved oxygen were determined in the control and test medium at the start and end of the exposure period. Total hardness and alkalinity of the control medium was determined at the start of the exposure period.

Test solutions

Vehicle:
yes
Remarks:
Standard hard water was prepared according to ASTM standards, Water and Environmental Technology, Section 11, Standard Guide for Conducting Acute Toxicity Tests with Fishes, Macroinvertebrates and Amphibians. E 729.
Details on test solutions:
The study was conducted as a range-finding limit test (without removal of test media) at a nominal exposure concentration range of 0.1, 1, 10 and 100 mg/L as Thio-Acid. The 100 mg/L test medium was prepared by direct addition of 0.1001 g of Thio-Acid to 1 litre of ASTM media. To aid the dispersion of the test article, the flask contents were treated with ultrasound for 30 minutes. Following that, the flask contents were placed onto a magnetic stirrer and stirred in the dark for 1 hour. The remaining exposure concentrations were prepared by serial dilution of the 100 mg/L test medium.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Juvenile Daphnia magna (less than 24 hours old) were taken from a laboratory culture maintained at Covance Laboratories Ltd. The culture was originally obtained from Sheffield University, Sheffield, UK.
The D.magna were cultured in 600 mg/L glass beakers containing 500 ml of standard hard water. New cultures were started with juvenile D.magna (less than 24 hours old), at a density of approximately 20 animals per litre. Each of the new cultures was fed daily with a concentrated suspension of Chlorella vulgaris at approximately 5x10^5 cells/ml. The algae was obtained from a five-litre fermenter-based culture, grown under the semi-axenic conditions at Covance Laboratories Ltd. The density of algal cells was counted using a haemocytometer and the required volume of the culture was calculated to achieve approximately 5x10^5 cells/ml in new cultures. The algae concentrated feed was stored in a fridge and used within two weeks. A seaweed extract was added once a week (at medium renewal) to each culture as a dietary supplement.
The water in each culture was renewed weekly. Any juveniles present in the cultures were removed on three occasions per week. Once they were discarded, the adults were returned to the cultures. Cultures were maintained up to a maximum of 42 days. Juveniles to be used in acute toxicity tests were collected from the third brood onwards from adults aged between 14 and 42 days.
All cultures, prior to and during toxicity tests, were maintained under fluorescent lighting on a 16-hour light: 8-hour dark photoperiod.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
164-166 mg/l (as CaCO3)
Test temperature:
Water temperature: 19.8-21.3C
pH:
7.3-7.4
Dissolved oxygen:
96-97% air saturation
Salinity:
alkalinity as CaCO3: 77-91 mg/l
Conductivity:
Not given
Nominal and measured concentrations:
Nominal: 0.1, 1, 10 and 100 mg/l as Thio-Acid
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
No concentration related immobility of Daphnia magna was observed in the control and all exposure concentrations during the range-finding limit test. As there was no immobility observed during the range-finding limit test, the 48-hour EC50 value and the corresponding no observed effect concentration (NOEC) for Daphnia magna exposed to Thio-Acid could not be determined. Therefore, the 48-hour EC50 value is considered to be >100mg/L, the highest nominal exposure concentration tested in the range-finding limit test.
Results with reference substance (positive control):
Not relevant

Any other information on results incl. tables

For tables, please see attached file "Acute aquatic daphnia tables and figures"

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
In error, observations of the Daphnia magna were omitted at 24 hours. As there was no significant concentration related immobility observed during the test, this omission does not affect the integrity of the test.
Conclusions:
As there was no immobility observed during the range-finding limit test, the 48-hour EC50 value and the corresponding no observed effect concentration (NOEC) for Daphnia magna exposed to Thio-Acid could not be determined. Therefore, the 48-hour EC50 value is considered to be >100mg/L, the highest nominal exposure concentration tested in the range-finding limit test.
Executive summary:

The acute toxicity of Thio-Acid to Daphnia magna was determined at approximately 20C in a 48-hour static range-finding limit test.

The study was carried out in accordance with the requirements of Annex V to Commission Directive 92/69/EEC: C.2. Acute toxicity for Daphnia and the OECD Guideline for Testing of Chemicals No 202, Part 1, Daphnia sp., Acute Immobilisation Test.

The study was conducted as a range-finding limit test,whereby four replicate vessels were prepared for the control and 100 mg/l treatments with two replicate vessels at the remaining concentrations. Each vessel contained five juvenile Daphnia magna. The 100 mg/L test media were prepared by direct addition of 0.1001 g of Thio-Acid to 1 litre of ASTM media. To aid the dispersion of the test article, the flask contents were treated with ultrasound for 30 minutes. Following that, the flask contents were placed onto a magnetic stirrer and stirred in the dark for 1 hour. The remaining exposure concentrations were prepared by serial dilution of the 100 mg/L test medium.

No concentration related immobility of Daphnia magna was observed in the control and all exposure concentrations during the range-finding limit test. As there was no immobility observed during the range-finding limit test, the 48-hour EC50 value and the corresponding no observed effect concentration (NOEC) for Daphnia magna exposed to Thio-Acid could not be determined. Therefore, the 48-hour EC50 value is considered to be >100mg/L, the highest nominal exposure concentration tested in the range-finding limit test. In error, observations of the Daphnia magna were omitted at 24 hours. As there was no significant concentration related immobility observed during the test, this omission does not affect the integrity of the test.