Producto P0310

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

For the determination of the actual test item concentrations, the following samples were taken:
Just before the start of the test:
- duplicate samples from the test medium (without daphnids)
- duplicate samples from the control (without daphnids)
After 48 hours:
- duplicate samples from the test medium (stability samples)
- duplicate samples from the control
For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling. All samples were deep-frozen (at about -20 ºC) immediately after sampling. Based on pre-experiments for investigation of the storage stability, the test item was found to be sufficiently stable in the test water under these storage conditions.
The concentration of the test item was analytically measured in the duplicate test medium samples of the single test concentration taken at the start and the end of the test. From the control, one of the duplicate samples was analyzed from each of the sampling times.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The test medium was prepared by dissolving 30.5 mg of test item completely in 300 mL of test water using ultrasonic treatment for 15 minutes and intense stirring for 15 minutes at room temperature in the dark. The test medium was prepared just before introduction of the daphnids (i.e., start of the test).

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: The study was performed with young daphnids of a clone of the species Daphnia magna Straus. A clone of this species (defined by the supplier as clone 5) was originally supplied by the University of Sheffield/UK in 1992.
- Age at study initiation (mean and range, SD): 6−24 hours old
- Method of breeding: the clone has been bred in the laboratories of RCC in reconstituted water of the quality identical to the water quality used in the tests (in respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests.
- Feeding during test: None

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

Water Hardness : 2.5 mmol/L (= 250 mg/L as CaCO3)

Test temperature:

Water temperature: 21 ºC during the test period. The test was performed in a temperature-controlled room (room temperature continuously monitored).

pH:

The pH values of the test medium and the control were between 7.9 and 8.0.

Dissolved oxygen:

The dissolved oxygen concentration in the test medium and the control was at least 8.1 mg/L.

Salinity:

Reconstituted test water: analytical grade salts were dissolved in purified water to obtain the following nominal concentrations:
CaCl2 × 2H2O : 2.0 mmol/L (= 294 mg/L)
MgSO4 × 7H2O : 0.5 mmol/L (= 123 mg/L)
NaHCO3 : 0.75 mmol/L (= 65 mg/L)
KCl : 0.075 mmol/L (= 5.8 mg/L)

Nominal and measured concentrations:

Nominal concentration of 100 mg/L.
Mean measured test item concentration of 78 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100-mL glass beakers filled with 50 mL of test medium
- Aeration: The test water was aerated prior to the start of the study until oxygen saturation was reached. During the test period, the test water was not aerated.
- No. of organisms per vessel: Five daphnids per replicate
- No. of vessels per concentration (replicates): Four replicates
- No. of vessels per control (replicates): Four replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted test water: analytical grade salts were dissolved in purified water
- Intervals of water quality measurement: At the start and at the end of the test, the pH values, the dissolved oxygen concentrations and the water temperature were determined in the single test concentration and the control.

OTHER TEST CONDITIONS
- Photoperiod: The test was performed in the dark to avoid photolytic degradation of the test item.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The daphnids were observed for immobility after 24 and 48 hours of exposure (daphnids not being able to swim within 15 seconds after gentle agitation of the test beaker are considered to be immobilized).

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Details on results:

In the control and at the nominal test concentration of 100 mg/L (mean measured concentration of 78 mg/L), no immobilized test organisms were observed during the test period of 48 hours.

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in December 2006 (48-hour EC50: 0.73 mg/L) indicated that the sensitivity of the test organisms was within the historical range (48-hour EC50 from 1996 to 2006: 0.53-1.1 mg/L).

At the start of the test, the analytically determined test item concentration in the analyzed test medium was 87% of the nominal value, proving a correct dosage of the test item. During the test period of 48 hours, a decrease of the test item concentration in the test medium was determined. The losses are probably the result of photolytic degradation. Though the test was carried out as far as possible in the dark, only 69% of the nominal value could be detected at the end of the test. The resulting mean measured test concentration (calculated as the geometric mean over all measurements of the test concentration) was 78 mg/L (i.e., 78% of the nominal value). The reported biological results are related both to the nominal and to the mean measured test item concentrations.

Validity criteria fulfilled:

yes

Remarks:

(immobilisation in the control was 0%; the dissolved oxygen concentration at the end of the test was greater than 3 mg/l in control and test vessels).

Conclusions:

The 48-hour NOEC and the 48-hour EC0 of the test item to Daphnia magna were determined to be at least the nominal concentration of 100 mg/L (mean measured concentration of 78 mg/L).

Executive summary:

The acute toxicity of the test item to Daphnia magna was determined in a 48-hour static test according to the EU Commission Directive 92/69/EEC, Part C.2 (1992) and the OECD Guideline for Testing of Chemicals, No. 202 (2004). A limit test was performed in accordance with the test guidelines to demonstrate that the test item has no toxic effect on the test organisms up to and including a nominal concentration of 100 mg/L. Thus, a single test item concentration of nominal 100 mg/L was tested. Additionally, a control was tested in parallel (test water without addition of the test item). At the start of the test, the analytically determined test item concentration in the analyzed test medium was 87% of the nominal value, proving a correct dosage of the test item. During the test period of 48 hours, a decrease of the test item concentration in the test medium was determined. The losses are probably the result of photolytic degradation. Though the test was carried out as far as possible in the dark, only 69% of the nominal value could be detected at the end of the test. The resulting mean measured test concentration was 78 mg/L. The reported biological results are related both to the nominal and to the mean measured test item concentrations. In the control and at the nominal test concentration of 100 mg/L (mean measured concentration of 78 mg/L), no immobilized test organisms were observed during the test period of 48 hours. The 48-hour NOEC (highest concentration tested without toxic effects after the exposure period of 48 hours) and the 48-hour EC0 of the test item to Daphnia magna were determined to be at least the nominal concentration of 100 mg/L (mean measured concentration of 78 mg/L). These values might even be higher, but nominal concentrations above 100 mg/L were not tested in accordance with the test guidelines. The 48-hour EC50 and the 48-hour EC100 were clearly higher than the nominal of 100 mg/L (mean measured concentration of 78 mg/L). These values could not be quantified due to the absence of toxicity of the test item at the nominal test concentration of 100 mg/L.

Description of key information

Key study: OECD guideline 202 and EU method C.2. GLP study.

The 48-hour NOEC and the 48-hour EC0 of the test item to Daphnia magna were determined to be at least the nominal concentration of 100 mg/L (mean measured concentration of 78 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Key study: OECD guideline 202 and EU method C.2. GLP study.

The 48-hour NOEC and the 48-hour EC0 of the test item to Daphnia magna were determined to be at least the nominal concentration of 100 mg/L (mean measured concentration of 78 mg/L).