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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
10 October - 12 October 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Version / remarks:
14 February 2017
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
- Concentrations: nominal 0.128, 0.28, 0.62, 1.36, and 3.0 mg/L
- Sampling method: Duplicate samples (~2 -2 mL) (from three replicates) were taken in plastic tubes from the control and at the applied test concentration levels at the beginning and at the end of the experiment.
- Sample storage conditions before analysis: After sampling, samples were frozen and kept approximately at -20°C prior to analysis.
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- A work solution with a concentration of 50.0 mg/L (nominal) was prepared with direct addition of the test item, mixed into the test medium (ISO Medium) using ultrasonic bath (~6 minutes). This work solution was diluted with ISO Medium to give the stock solution of 3.0 mg/L (nominal) (60.0 mL work solution was filled up with test media to 1000 mL). The test solutions were prepared by appropriate dilution of this stock solution just before introduction of the Daphnia (start of the treatment).
- Controls:
Untreated Control: The dilution water (ISO-medium) was used without addition of the test item.
Reference Control: For the evaluation of the quality of the Daphnia clone and the experimental conditions, Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.
The date of the last study (Study Code: 17/058-023DA) with reference item Potassium dichromate (batch no.: A0345704) is: 08 - 09 March 2017. The 24h EC50: 0.64 mg/L, (95 % confidence limits: 0.59 – 0.68 mg/L).
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia
- Strain/clone: magna
- Source: István Szent University, 2100 Gödöllő, Páter Károly u. 1, Hungary
- Age of parental stock (mean and range, SD): < 24 h old at beginning of test.
- Feeding during test: no

ACCLIMATION
- Acclimation period: There was no acclimatization because the water used was similar to the culture water.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
none
Hardness:
The reconstituted water (ISO medium) had a total hardness of 247 mg/L (as CaCO3)
Test temperature:
20.1 - 20.7 °C
pH:
7.67 - 7.98
Dissolved oxygen:
8.3 – 8.6 mg/L
Salinity:
no data
Conductivity:
no data
Nominal and measured concentrations:
The nominal concentrations of test item used in the main experiment were: 0.128, 0.28, 0.62, 1.36, and 3.0 mg/L. The corresponding measured geometric mean test item concentrations were: 0.114, 0.25, 0.64, 1.38, and 3.01 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: glass
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Biomass loading rate: >= 5 mL test solution/animal

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water (ISO medium, according to OECD 202) was used as dilution water. The same composition of reconstituted water was used for the tests and for breeding the test animals.
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16-hour light and 8-hour dark cycle
- Light intensity: not stated

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility at 24 and 48 h


RANGE-FINDING STUDY
- Test concentrations: 0, 0.1, 1, 10, 100 mg/L (nominal)

- Results used to determine the conditions for the definitive study: 0 & 0.1 mg/L - 0/10 immobilised; 1 mg/L - 5/10 immobilised; 10 & 100 - 10/10 immobilised
Reference substance (positive control):
yes
Remarks:
Potassium dichromate
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
1.42 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
0.64 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Behavioural abnormalities: none reported
- Mortality of control: 0
- Other adverse effects control: none reported
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none reported
- Effect concentrations exceeding solubility of substance in test medium: no
Results with reference substance (positive control):
Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.
The date of the last study (Study Code: 17/058-023DA) with reference item Potassium dichromate (batch no.: A0345704) is: 08 - 09 March 2017. The 24h EC50: 0.64 mg/L, (95 % confidence limits: 0.59 – 0.68 mg/L).
Reported statistics and error estimates:
24h EC50 - 95 % conf. limits: 2.43 – 3.87 mg/L
48h EC50 - 95 % conf. limits: 1.20 – 1.72 mg/L
Validity criteria fulfilled:
yes
Conclusions:
The 48h EC50 value: 1.42 mg/L (measured) (95 % conf. limits: 1.20 – 1.72 mg/L)
Executive summary:

Acute toxicity of the test item on Daphnia magna was assessed in an acute immobilisation test, over an exposure period of 48 hours in a static test system. Because significant immobility was observed at examined concentration levels during the preliminary range-finding test, five test concentrations in a geometric series (factor 2.2) and one control group were tested in the definitive test under static conditions. The test concentrationswereanalytically determined at the start and at the end of the experiment. The nominal concentrations of test item used in the main experiment were: 0.128, 0.28, 0.62, 1.36, and 3.0 mg/L.The corresponding measured geometric mean test item concentrations were: 0.114, 0.25, 0.64, 1.38, and 3.01 mg/L. As the measured concentrations deviated more than 20 per cent from the nominal in one case, biological results are based on the measured geometric mean test item concentrations. Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentrations and for the control as well. The 24 and 48 hours EC50 values of the test item were calculated using Probit analysis by SPSS PC+ software. The 48h EC100 value of the test item were determined directly from the raw data. For the determination of the LOEC and NOEC, the immobilization at the test concentrations was tested on significant differences to the control values by Dunnett’s Test using TOXSTAT software. All validity criteria were met during this study.

Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of the test item were the following:

The 24h EC50 value: 2.93 mg/L (measured) (95 % conf. limits: 2.43 – 3.87 mg/L)

The 48h EC50 value: 1.42 mg/L (measured) (95 % conf. limits: 1.20 – 1.72 mg/L)

The 48h EC100 value: 3.01 mg/L (measured)

The 48h No-Observed Effect Concentration (NOEC): 0.64 mg/L (measured)

The 48h Lowest Observed Effect Concentration (LOEC): 1.38 mg/L (measured)

Description of key information

48-h EC50 = 1.42 mg/L (Daphnia magna, OECD TG 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
1.42 mg/L

Additional information

Acute toxicity of the test item on Daphnia magna was assessed in an acute immobilisation test, over an exposure period of 48 hours in a static test system. Because significant immobility was observed at examined concentration levels during the preliminary range-finding test, five test concentrations in a geometric series (factor 2.2) and one control group were tested in the definitive test under static conditions. The test concentrations were analytically determined at the start and at the end of the experiment. The nominal concentrations of test item used in the main experiment were: 0.128, 0.28, 0.62, 1.36, and 3.0 mg/L. The corresponding measured geometric mean test item concentrations were: 0.114, 0.25, 0.64, 1.38, and 3.01 mg/L. As the measured concentrations deviated more than 20 per cent from the nominal in one case, biological results are based on the measured geometric mean test item concentrations. Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentrations and for the control as well. The 24 and 48 hours EC50values of the test item were calculated using Probit analysis by SPSS PC+ software. The 48h EC100 value of the test item was determined directly from the raw data.For the determination of the LOEC and NOEC, the immobilization at the test concentrations was tested on significant differences to the control values by Dunnett’s Test using TOXSTAT software. All validity criteria were met during this study.

Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of the test item were the following:

The 24h EC50 value:2.93 mg/L (measured) (95 % conf. limits: 2.43 – 3.87 mg/L)

The 48h EC50 value: 1.42 mg/L (measured) (95 % conf. limits: 1.20 – 1.72 mg/L)

The 48h EC100 value: 3.01 mg/L (measured)

The 48h No-Observed Effect Concentration (NOEC): 0.64 mg/L (measured)

The 48h Lowest Observed Effect Concentration (LOEC): 1.38 mg/L (measured)