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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:
August-September 2018
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)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Batch 44034
Description: Cream to light grey powder
Expiry date: 30 November 2019
Storage conditions: Controlled room temperature (15-25 ºC, below 70 RH%).

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
Formulation
A stock solution with a nominal concentration of 100 mg/L was prepared with direct addition of the test item, mixed into the test medium (ISO Medium) using ultrasonic bath for approximately 2 minutes. As a Limit test was carried out, further dilution of stock solution was not performed.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Source: István Szent University,
2100 Gödöllő, Páter Károly u. 1, Hungary
Breeding The Daphnia are bred in Ecotoxicological Laboratory of Citoxlab Hungary Ltd.
The health of the stock animals is continuously monitored by visual daily checking. Abnormal behaviour or significant decrease of population is recorded.
Justification of strain: Daphnia magna is the standard species of the acute immobilisation test.
Number of animals: There were 20 animals in test group and control group respectively, divided into 4 replicates
(5 animals / replicate)
Age of the animals: They were less than 24 h old at the beginning of the test
Acclimatization: There was no acclimatization because the water used was similar to the culture water.

Study design

Test type:
static
Water media type:
other: Reconstituted water (ISO medium, according to OECD 202)
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
The reconstituted water (ISO medium) had a total hardness of 245 mg/L (as CaCO3).
Test temperature:
The water temperature was measured at the start of the experiment and in 24-hour intervals thereafter in each test vessel. The test temperature was in the range of 20.1 – 20.2°C measured in the test vessels.
The additionally measured temperature in the climate chamber was between 19.7 – 21.0°C.
pH:
The pH of the test solution was not adjusted and not varied by more than 1.5 units in any one test. The pH was measured at the start and at the end of the experiment in each test vessel and was in the range of 7.51 – 7.73.
Dissolved oxygen:
The dissolved oxygen concentration was measured in each test vessel at the start and at the end of the test and was in the range of 8.2 – 8.6 mg/L.
Nominal and measured concentrations:
Nominal concentrations
[mg/L] 0.1 1 10 100
Details on test conditions:
The test was carried out in 16-hour light and 8-hour dark cycle.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC100
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
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:
LOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Results with reference substance (positive control):
The 24h EC50: 0.71 mg/L, (95 % confidence limits: 0.66 – 0.76 mg/L)
Potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.
The date of the last study (Study Code: 18/178-023DA) with reference item Potassium dichromate (batch no.: A0345704) is: 19- 20 June 2018.
Reported statistics and error estimates:
VALIDITY
There were no immobilized animal in the control group and the dissolved oxygen concentration at the end of the test in control and test vessels was more than 3 mg/L.
All validity criteria were within acceptable limits and therefore the study can be considered as valid.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of Sodium [(6-hydroxy-4-methyl-2-oxo-2H-1-benzopyran-7-yl)oxy]acetate were the followings:
 The 24h and 48h EC50value:     >100 mg/L (nominal)
The 48h EC100value:                  >100 mg/L (nominal)
The 48h No-Observed Effect Concentration (NOEC):            100 mg/L (nominal)
The 48h Lowest Observed Effect Concentration (LOEC):   >100 mg/L (nominal)
 
Executive summary:

Acute toxicity of Sodium [(6-hydroxy-4-methyl-2-oxo-2H-1-benzopyran-7-yl)oxy]acetate on Daphnia magna was assessed in an Acute immobilisation test, over an exposure period of 48 hours in a static test system.

Because no toxic response was observed during the preliminary range-finding test, a Limit Test was carried out using only one test concentration (100 mg/L) and one control groupin the definitive test. The test concentration was analytically determined at the start and at the end of the experiment. Measured concentration was 99.2 mg/L at the start and 101 mg/L at the end of the experiment. As the measured concentration deviated not more than 20 per cent from the nominal, biological results are based on the nominal concentration. Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentration and for the control.

All validity criteria were met during this study.