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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:
From 2017-09-13 to 2017-10-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
3 April 2004
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Appearance: solid yellow powder

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 10.0, 4.55, 2.07, 0.939, 0.427 mg/L and control
- Sampling method: samples taken from all test item concentrations and control at test start and after 24 hours from fresh and aged solutions and after 48 hours from aged solutions. For each sampling also a retain sample was taken.
- Sample storage conditions before analysis: the test medium samples (10 mL) were mixed with 50 μL formic acid and stored deep-frozen (≤ - 18 °C)

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Stock solution: weight necessary amount of test item in volumetric flask and added test medium up to the benchmark, then homogenised by shaking and one minute of sonication.
- Lower test solutions: dilution of stock solution with test medium
- Test concentration: 10.0, 4.55, 2.07, 0.939, 0.427 mg/L and control.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna Straus
- Strain/clone: Clone V
- Source: bred in the laboratory and were originally purchased from the Federal Environment Agency in Berlin/Germany.
- Age: Freshly hatched daphnids less than 24 hours old
- Feeding during test: no
- Breed method: bred as single culture (1 daphnid per 100 mL) in Elendt M4 medium at 20 ± 2 °C in a climatic chamber with 16 hours of illumination and 8 hours of darkness. medium changed three times per week. Fed with single cell green algae at least three times a week
- Condition: pH value of the aerated water: within a range of 6.0 – 9.0; dissolved oxygen: above 60 % saturation; total hardness: 140 - 250 mg/L (as CaCO3), corresponding to 7.8 - 14°dH.
- Young daphnids separation: using pipette

Study design

Test type:
semi-static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
13°dH (232 mg/L CaCO3)
Test temperature:
20.0 ± 0.3 °C
pH:
7.92 ± 0.13
Dissolved oxygen:
9.1 ± 0.1 mg/L
Nominal and measured concentrations:
Nominal: 10.0, 4.55, 2.07, 0.939, 0.427 mg/L
Measured: 7.40, 3.50, 1.86, 0.911, 0.346 mg/L
Details on test conditions:
TEST SYSTEM
- Feeding: none
- Test vessels: four 100 mL glass beakers per concentration, each filled with ~ 50 mL, one additional replicate for physico–chemical measurements without test organisms.
- Type: covered with a glass plate
- Loading: ~ 10 mL of test solution for each animal
- Aeration: none
- Number of animals: 20 per concentration in 4 replicates of 5 daphids
- Renewal: 24 h
- Exposure to light: none

TEST MEDIUM / WATER PARAMETERS
- Test medium: Elendt M4 medium
- pH-value: 7.91
- Dissolved oxygen concentration: 9.3 mg/L
- Total hardness: 13°dH (232 mg/L as CaCO3).

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Biological assessment: immobilised daphnids counted after 24 h and 48 h
- Physico-chemical assessment: test temperature, pH-value, oxygen concentration measured at t = 0 h fresh and t = 24 h from fresh test solutions and after t = 24 h and t = 48 h from aged test solutions in one separate replicate per test item concentration without test organisms

RANGE-FINDING STUDY
- Test concentrations: 100, 10.0 and 1.00 mg/L and control
- Results used to determine the conditions for the definitive study: After 48 hours of exposure no immobilisation was observed in the control and at test item concentration 1.00 mg/L. 100 % of the daphnids were immobile at 10.0 and 100 mg/L.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
1.72 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
0.939 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
1.58 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
0.911 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Study validity: control immobilisation after 48 hours was 0 %. Dissolved oxygen concentration at the end of the test was ≥ 8.9 mg/L. The validity criteria were met.
- Biological Assessment: see any other information on results

Results with reference substance (positive control):
Tested at 1.00 and 2.00 mg/L with 20 test organisms per test concentration.
The results indicate an EC50 (24 h) of the reference item potassium dichromate between 1.00 mg/L and 2.00 mg/L.
Since the results are in accordance with the requirements of the OECD guideline 202 and fall within the historical data generated with the reference item at the testing facility, the daphnids were suitable for the determination of the toxicological effects of the test item.
Reported statistics and error estimates:
The values for EC50 were determined by Weibull analysis using linear max. likelihood regression.

Any other information on results incl. tables

Biological results after 24h

  Test concentration (mg/L) - Nominal
control 0.427 0.939 2.07 4.55 10
group 1 0 0 0 0 5 5
group 2 0 0 0 2 5 5
group 3 1 0 0 0 5 5
group 4 0 0 0 3 5 5

Biological results after 48h:

  Test concentration (mg/L) - Nominal
control 0.427 0.939 2.07 4.55 10
group 1 0 0 0 5 5 5
group 2 0 0 0 4 5 5
group 3 0 0 0 3 5 5
group 4 0 0 0 4 5 5

Analytical results

Test item nominal concentration (mg/L) Sampling Measured concentration (mg/L) % of nominal Geometric mean concentration (mg/L)
Control 0 fresh n.d. - -
24 aged n.d.
24 fresh n.d.
48 aged n.d.
0.427 0 fresh 0.441 103 81
24 aged 0.182 43
24 fresh 0.47 110
48 aged 0.372 87
0.939 0 fresh 1.13 120 97
24 aged 0.755 80
24 fresh 1.13 120
48 aged 0.714 76
2.07 0 fresh 1.61 78 90
24 aged 1.72 83
24 fresh 2.3 111
48 aged 1.86 90
4.55 0 fresh 4.21 93 77
24 aged 2.38 52
24 fresh 4.29 94
48 aged 3.51 77
10 0 fresh 9.13 91 74
24 aged 4.74 47
24 fresh 9.56 96
48 aged 7.27 73

-=not calculated; n.d.=not detectable; LOQ= 0.04 mg test item/L

EC50 and NOEC-values of daphnids exposed to the test item:

 

Nominal [mg/L]

Actual [mg/L]

 

24 h

48 h

24 h

48 h

NOEC

0.939

0.939

0.911

0.911

EC50

2.54

1.72

2.17

1.58

95% confidence limit of EC50

2.11-3.48

1.49-1.96

1.88-3.45

1.37-1.79

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The EC50 (48 h) for immobilisation was determined to be 1.72 mg/L (nominal) and 1.58 mg/L (actual). The corresponding NOEC (48 h) was 0.939 mg/L (nominal) and 0.911 mg/L (actual).
Executive summary:

The immobilisation effect of test item was determined on the water flea Daphnia magna under worst-case exposure conditions according to OECD 202. Following a semi-static non-GLP range-finding test with nominal concentrations of 100, 10.0 and 1.00 mg/L and control, a semi-static main test with nominal concentrations of 10.0, 4.55, 2.07, 0.939 and 0.427 mg/L and control was performed. Since he substance is known to undergo photomodification, the test was performed in the dark.

The values for EC50 were determined by Weibull analysis using linear max. likelihood regression. The NOEC was established based on the highest concentration at which the immobilisation is not higher than the allowed control immobilisation (10 % immobilisation). Water quality parameters of pH-value and dissolved oxygen concentration measured at 0 and 48 h were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled. The measured content of test item was between 80 and 120 % of nominal at test start.

According to the results of the test, the EC50 (48 h) was determined to be 1.72 mg/L (nominal) and 1.58 mg/L (actual). The corresponding NOEC (48 h) was 0.939 mg/L (nominal) and 0.911 mg/L (actual).