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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: according to guideline, GLP compliant

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Storage of samples: samples were analysed without storage. Samples treatment: no treatment

Test solutions

Vehicle:
no
Details on test solutions:
A stock solution of DIBENZYL TRITHIOCARBONATE diluted in water was prepared at the beginning of the test (time 0) by mixing 5 mg of DIBENZYL TRITHIOCARBONATE in one litre of dilution water. The mixture was kept under stirring during 18 hours. The solution was then filtered through HAWP 04700 Millipore filter (0.45 pm) allowing to obtain a limpid solution. The solution obtained was clear and colourless.

In the preliminary test, daphnids were exposed under static conditions to a series of 5 concentrations (5, 2.5, 1, 0.5 and 0.1 mg/L) of DIBENZYL TRITHIOCARBONATE in dilution water (composition detailed in Annex 1). The toxic effect measured during the assay was the inhibition mobility over a time period of 48 hours.

Approximately 90% of the final volume of the test solution was added into test flasks. Five Daphnia magna aged from 6 to 24 hours were added into each test flask, which were then totally filled with the test solution (30 mL). Two replicates were prepared for each concentration. Two control flasks were prepared under the same conditions, with no test item. Test flasks were incubated in darkness at a temperature between 20.0 °C and 20.5 °C.

After 48 hours of incubation, mobile Daphnia magna were counted.
Dissolved 02 and pH were measured at the highest tested concentration and in the control. Results of the preliminary test served to define the concentration range used in the definitive test.

As results of the preliminary test showed no toxicity even at the higher nominal concentration, it was decided to run a limit test at 5 mg/L (nominal concentration, saturated solution) which is a concentration exceeding water solubility of the substance (ca 0.34 mg/L). This has been done in order to improve toxicity figures.

A stock solution of the test item was prepared 18 hours before the beginning of the test (time 0) by mixing 5 mg of DIBENZYL TRITHIOCARBONATE in 1 litre of dilution water.
At the end of this stirring period, which corresponded to the day on which the test was started, the solution was filtered on a Millipore membrane HAWP 047000 at 0.45 µm. The parent solution obtained was clear, colourless, slightly odorous.

The test was performed at the nominal concentration: 5 mg/L. Number of replicates: 4

Approximately 90% of the final volume of the test solution was added into test flasks. Five Daphnia magna aged from 6 to 24 hours were added into each test flask, which were then totally filled with the test solution (30 mL). 4 replicates were prepared for each concentration. 4 control flasks were prepared under the same conditions, with no test item. Test flasks were incubated in darkness at a temperature of 20.9 °C.

After 24 hours of incubation, mobile Daphnia magna were counted and flasks replaced under incubation. At time 48 hours mobile Daphnia magna were counted.

Test organisms

Test organisms (species):
Daphnia magna

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Post exposure observation period:
no

Test conditions

Hardness:
Chemical reagents used for the preparation of dilution water are of « analytical grade ». Dilution water is prepared according to the protocol described in standard NF EN 1SO 6341:
The following stock solutions are prepared:
CaCI2, 2H2O: 11.76 g per litre of water, Merck Ref. 1.02382.5000
MgSO4, 7H2O: 4.93 g per litre of water, Merck Ref. 1.05886.1000
NaHCO3: 2.59 g per litre of water, Prolabo Ref. 27778.293
KCI: 0.23 g of per litre of water, Prolabo Ref. 26764.232
Dilution water is obtained by adding 25 mL of each of the stock solutions in a final volume of 1 litre and then aerating the solution until oxygen saturation.
Sum of Ca and Mg ions in dilution water is of 2.5 mmol/L and ratios of Ca/Mg et Na/K are 4 and 10 respectively.
pH:
Nominal concentrationsmg/L
To T48h
0 7.97 7.75
5 7.90 7.68
Dissolved oxygen:
Nominal concentrationsmg/L Dissolved 02 (mgIL)
To T48h
0 9.1 8.4
5 8.2 7.5
Salinity:
according to the protocol described in standard NF EN 1SO 6341
Nominal and measured concentrations:
Loading rate the definitive (limit) test : 5 mg/L
Concentrations of DIBENZYL TRITHIOCARBONATE in the definitive test
NominalConcentration(mg/L) Measured in non inoculated solutions
Initial(mg/L) Final(mg/L)
0 (T) < DL < DL
5 < DL < DL
< DL : concentration lower than the Detection Limit of the analytical method (12.4 µgIL).
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 0.34 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
EC0
Effect conc.:
> 0.34 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Effect concentrations exceeding solubility of substance in test medium: yes
- Mortality of control: no

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
With a loading rate of 5 mg/L no toxicity was observed, therefore, as water solubility limit has been determined (according to OECD 105) to be 0.34 mg/L, there is no acute toxicity up to this concentration.