Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

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:
28 Apr - 30 Apr 2021
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2021
Report date:
2021

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
adopted April 13, 2004
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-(4-chloro-2,6-dimethylphenyl)acetic acid
EC Number:
858-362-8
Cas Number:
186748-50-5
Molecular formula:
C10H11ClO2
IUPAC Name:
2-(4-chloro-2,6-dimethylphenyl)acetic acid

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Sampling method: Duplicate samples from the freshly prepared test media of all test concentrations and the control were taken at the start of the test.
For the determination of the stability of the test item under the test conditions and of the maintenance of the test item concentrations during the test period, duplicate samples from the test media of all test concentrations and the control were collected at the end of the test (after 48 hours) by pouring together the contents of the test beakers of each treatment. All samples were diluted by a factor of 2 with acetonitrile.

- Sample storage conditions before analysis: deep frozen

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
The test item is not well soluble in test medium. To avoid physical effects of undissolved test item on the daphnids, no concentrations above the solubility limit of the test item in test water was tested. Therefore, a supersaturated stock solution of nominal 100 mg test item/L was prepared by suspending 98.6 mg test item in 986 mL test water. The stock suspension was stirred for 24 hours at room temperature in the dark to dissolve as much test item as possible. Then, non-dissolved fractions of the test item were separated from the test medium by membrane filtration (0.45 µm cellulose acetate filter). The solution with dissolved test item was used as the test medium of the highest test concentration and to prepare the desired 1:3.3, 1:10.9, 1:35.9 and 1:118.6 dilutions.
The test media were prepared just before introduction of the daphnids (= start of the test).
In the control, test water was used without addition of the test item.
Nominal 100, 30.3, 9.2, 2.8 and 0.8 mg test item/L (spacing factor 3.3) and a control.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
Daphnia magna (Straus), clone 5
Age at Test Start: From 3.5 to 22.75 hours old
Source: The daphnids introduced in the test were taken from ibacon's in-house laboratory culture.
The daphnids were bred in the laboratories of ibacon under similar temperature and light conditions as used in the test. The cultivation of the parental daphnids was performed in Elendt M4 medium. The test organisms were not first brood progeny. The daphnids in the stock culture were fed at least on all working days with green algae (Desmodesmus subspicatus) freshly grown in the laboratories of ibacon.
Feeding during the test: none
Acclimatisation: was not necessary, since the test was performed in the same medium as the culturing.

Study design

Test type:
static
Water media type:
other: Reconstituted water, Elendt "M4"
Limit test:
no
Total exposure duration:
48 h

Test conditions

Hardness:
Water Hardness: 2.5 mmol/L (= 250 mg/L) as CaCO3
Test temperature:
Water Temperature: 20.2 °C at test start; 20.4 °C at test end
pH:
7.9 to 8.0 at test start;
7.6 to 8.1 at test end; and thus the pH-value did not vary by more than 1.5 units
Dissolved oxygen:
9.5 to 9.8 mg/L at test start;
9.6 to 9.7 mg/L at test end
Nominal and measured concentrations:
nominal: 100, 30.3, 9.2, 2.8 and 0.8 mg test item/L (spacing factor 3.3) and a control.

The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to nominal values since the concentrations of the test item were within ± 20% of the nominal concentrations during the test.
Details on test conditions:
Test Vessel: Glass beakers of 100 mL volume containing approximately 60 mL of test medium. The test vessels were covered with a lid to reduce the loss of water due to evaporation and to avoid the entry of dust into the solutions.
Light Regime: 16 h light : 8 h dark
Light Intensity: The light intensity was 420 to 600 lux (measured once during the test).
Introduction of Daphnids: 20 daphnids per control and test concentration, divided into 4 groups of 5 animals, each group in 60 mL test medium
Replicates: The test was performed with four replicates per treatment group. Exposure Time: 48 hours
Test Procedure: A static test was performed.
Feeding: None
Sampling: Samples were taken at test start (0 hours) and test end (48 hours)

Test Parameter:
Immobility: The mobility of the daphnids was determined by visual observation after 24 and 48 hours. Those animals that are not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile (even if they could still move their antennae).

No pre-experiments were performed.
Reference substance (positive control):
yes
Remarks:
For the evaluation of the quality of the Daphnia clone and the consistency of the experimental conditions, the reference item potassium dichromate is tested at least twice a year to demonstrate satisfactory test conditions.

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
45.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC10
Effect conc.:
27.1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
9.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
LOEC
Effect conc.:
30.3 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
Signs of Intoxication after 48 Hours:
After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the test item concentration of nominal 9.2 mg test item/L. At the concentration of nominal 30.3 mg test item/L, 3 daphnids were immobile and all 20 daphnids were immobile at the concentration of nominal 100 mg test item/L
Results with reference substance (positive control):
Results of the most recent Test with the Reference Item Potassium Dichromate
Dose response test: 0.35, 0.53, 0.8, 1.2 and 1.8 mg/L
EC50 24h: > 1.8 mg/L
NOEC 24 h: 0.8 mg/L
LOEC 24 h: 1.2 mg/L
EC50 48 h: 1.21 mg/L
NOEC 48 h: 0.35 mg/L
LOEC 48 h: 0.53 mg/L

The reference test was valid; The results indicate that the sensitivity of the daphnids was consistent with the level proposed by the OECD 202 guideline (EC50-24 h between 0.6 and 2.1 mg potassium dichromate/L).
Reported statistics and error estimates:
The 24-hour and 48-hour EC50, EC20 and EC10 and the 95 % confidence limits were calculated by Weibull analysis.
The NOEC and LOEC after 24 and 48 hours were calculated using Fishers exact test with Bonferroni correction (24h) and Step-down Cochran Armitage test procedure (48h).
The software used to perform the statistical analysis was ToxRat Professional, Version 3.3.0, ToxRat Solutions GmbH.

Any other information on results incl. tables

Validity criteria























Criterionvalue requiredvalue obtainedfullfilled
Control immobilisation rate< 10%0%yes
Dissolved oxygen concentrationat the end of the test >= 3 mg O2/L 9.6 mg O2/L in in all treatment groups at the end of the testyes

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
see any other information on results
Conclusions:
The toxic effect of the test item to Daphnia magna was assessed in a static concentration-response test. The 48-hour NOEC was determined to be 9.2 mg test item/L. The 48-hour LOEC was determined to be 30.3 mg test item/L and the 48-hour EC50 value was calculated to be 45.4 mg test item/L.

The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to nominal values since the concentrations of the test item were within ± 20 % of the nominal concentrations during the test.
Executive summary:

Test Species: Daphnia magna, clone 5; 3.50 to 22.75 hours  old


Test Design: This study encompassed 6 treatment groups (5 dose rates of the test item and a control) each containing 20 individuals. The mobility of the daphnids was determined in a static 48-hour test by visual observation after 24 and 48 hours. 


Endpoints: Number of immobile organisms after 24 and 48 hours


Test Concentrations: Nominal 100, 30.3, 9.2, 2.8 and 0.8 mg test item/L (spacing factor 3.3) and a control.


Test Conditions: Water temperature: 20.2 to 20.4 °C; pH value: 7.6 to 8.1; dissolved oxygen concentration: 9.5 to 9.8 mg/L; photoperiod: 16 h light - 8 h dark; light intensity: 420 to 600 lux; and thus were within the ranges requested by guideline OECD 202


Results: After 48 hours of exposure no immobilisation of the test animals was observed in the control and up to and including the test item concentration of nominal 9.2 mg test item/L. At the concentration of nominal 30.3 mg test item/L, 3 daphnids were immobile and all 20 daphnids were immobile at the concentration of nominal 100 mg test item/L.

































Parameter 
 after 48 h
EC50 mg test item/L45.4
EC20 mg test item/L33.3
EC10 mg test item/L27.1
NOEC mg test item/L9.2
LOEC mg test item/L30.3

Analytical Results:


The quantification of the test item in the test samples was performed using liquid chromatography with UV detection. At the start of the test 97 % of the nominal test concentrations were found (average of all test concentrations). After 48 hours test duration, 96 % of the nominal value was determined (average of all test concentrations). During the test the daphnids were exposed to a mean of 97 % of nominal.


Conclusion:


The toxic effect of the test item to Daphnia magna was assessed in a static concentration-response test. The 48-hour NOEC was determined to be 9.2 mg test item/L. The 48-hour LOEC was determined to be 30.3 mg test item/L and the 48-hour EC50 value was calculated to be 45.4 mg test item/L.


The initial concentrations and the maintenance of the exposure concentrations during the test were verified in the analytical part. All reported results refer to nominal values since the concentrations of the test item were within ± 20 % of the nominal concentrations during the test.