Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
The rationale for the read-across approach is attached in section 13. See the link in the 'Cross-reference' table.
Reason / purpose:
read-across source
Reason / purpose:
read-across: supporting information
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
14.3 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CI: 13.1-15.4 mg/L / based on read-across
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 April 2006 - 25 May 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
adopted April 13, 2004
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
- Concentrations: control, and all test concentrations
- Sampling method: at test start 20 mL form the test media preparation flasks (at each concentration)
- Sample storage conditions before analysis: not reported (analysis of freshly collected samples assumed)
Vehicle:
no
Remarks:
Trials were performed to check if a solvent addition had an effect on measured test substance concnetrations. It was concluded that there was no advantage of using a solvent, and therefore test media were prepared by direct addition of the substance.
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: At the start of the test each test media was prepared by direct addition of the appropriate amount of the test substance (0.88, 1.96, 4.25, 9.40, 20.73, 45.5 and 100.12 mg) into a glass weighing vessel, to which was added ca 10 mL of Daphnia dilution water (ASTM). The vial and contents were treated with ultrasound for ca 1 minute, added to 1 litre volumetric flasks and made up to volume with ASTM. The volumetric flasks and contents were treated with ultrasound for an additional 30 minutes and then stirred overnight in the dark. Prior to use each test medium was filtered through a 0.45 μm pore size filter.
- Controls: The control treatment was prepared by adding test medium only to control test vessels.

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: Daphnia magna
- Source: healthy laboratory cultures, held and maintained at Covance Laboratories Ltd (parent culture was originally obtained from the Environment Agency’s National Centre for Ecotoxicology and Hazardous substances (laboratory)
- Age of test animals: <24 hours old
- Feeding during test: no

ACCLIMATION
- Acclimation period: <24 hours
- Acclimation conditions (same as test or not): yes

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES:
The D. magna are cultured in 600 mL glass beakers containing 500 mL of standard hard water. New cultures are initiated with juvenile D. magna (less than 24 hours old), at a density of 20 daphnids per litre. The cultures are fed daily with a concentrated suspension of Chlorella vulgaris. A seaweed extract was also added at each medium renewal as a dietary supplement. Also, synthetic mediums are considered to be deficient in some essential trace elements such as selenium. Deficiency in selenium has been shown to affect the moulting process of aquatic crustaceans, which can have a deleterious effect on subsequent juvenile production and parental survival (Elendt & Bias, 1990). Therefore, at each media renewal, 50 μL of a 47.8 mg/L sodium selenate solution (as a source of selenium) was added to each culture vessel to maintain the
integrity of the D. magna carapace.
The water in each culture was renewed weekly. Juveniles were removed when present in cultures at least three times per week using a sieve. Cultures were maintained up to a maximum of 42 days. Juveniles for use in acute toxicity tests were collected from the second brood onwards. Approximately 24 hours before a test was set up, juveniles present in the cultures were removed and discarded. Over the next 24 hours, juveniles for use in the test were removed from the culture using a wide bore pipette and transferred to fresh culture medium. The juveniles were then left for at least 1 hour before selecting actively swimming individuals for use.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
165 mg/L (as CaCO3)
Test temperature:
20.4-21.0
pH:
t=0: 7.6-7.9
t=48: 8.2
Dissolved oxygen:
t=0: 6.8-9.1
t=48: 8.6-8.8
Nominal and measured concentrations:
- Nominal: 0.88, 1.94, 4.27, 9.39, 20.7, 45.5 and 100 mg/L; and a control
- Measured: 1.21, 1.89, 3.55, 8.45, 16.7, 24.2 and 26.5 mg/L; no substance measured in the control (Mean value determined as the geometric mean of all measured concentrations)
Details on test conditions:
TEST SYSTEM
- Test vessel: 150 mL glass crystallising dishes, covered with a transparent petri-dish lid
- Fill volume: 100 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Standard hard water was prepared according to (ASTM) Standards, Water and Environmental Technology, Section 11, Standard Guide for Conducting Acute Toxicity Tests with Fishes, Macroinvertebrates and Amphibians, E 729, using analytical grade reagents and reverse-osmosis (RO) water
- Alkalinity: 70 mg/L (as CaCO3)
- Culture medium different from test medium: no
- Intervals of water quality measurement: temparature - continuously (in a separate test vessel in the study area); pH and dissolved oxygen - at test start and test end

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: All cultures, prior to and during toxicity tests, are maintained under fluorescent lighting on a 16-hour light: 8-hour dark photoperiod

EFFECT PARAMETERS MEASURED
Evidence of immobility (after 24 and 48 h). The observations differentiated between animals immobilised and submerged in the body of the test media and those that were held at the surface of the test media.

RANGE-FINDING STUDY
- Test concentrations: 0.1, 1, 10 and 100 mg/L (nominal)
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
14.3 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks on result:
other: 95% CI: 13.1-15.4 mg/L
Details on results:
- Behavioural abnormalities: none reported
- Other biological observations: none reported
- Mortality of control: no
- Other: At the start of the test, the control and all treatments appeared as colourless solutions. The appearance of all treatments (with the exception of the 100 mg/L treatment), was unchanged for the duration of the test. At 24 and 48 hours the 100 mg/L treatment appeared as non-homogeneous liquid dispersions with white flaky particles on the base of the vessels. At 24 hours the flaky particles were collected around the immobile and mobile D. magna.
- All water quality parameters were within those recommended in the test guidelines.
Reported statistics and error estimates:
Toxicity values were calculated using a probit method of statistical analysis (Stephan et al.,1978).
95% confidence interval values are presented in the results field.

Table: Immobilisation of Daphnia magna after 24 hours exposure to test material during the acute toxicity definitive test

Mean measured concentration (mg/L)

Number of daphnids exposed

Mobile Daphnia

Immobile daphnia

Bottom

Surface

Bottom

Surface

Control

20

20

-

-

-

1.21

20

20

-

-

-

1.89

20

20

-

-

-

3.55

20

20

-

-

-

8.45

20

20

-

-

-

16.7

20

20

-

-

-

24.2

20

16

-

4

-

26.5

20

7*

-

13

-

* Daphnia swimming slowly / twitching antenna

MEASURED TEST CONCENTRATIONS

- At the start of the test, measured concentrations of the test substance in the control, 0.88, 1.94, 4.27, 9.39, 20.7, 45.5 and 100 mg/L test media were 0, 1.34, 2.05, 3.53, 8.38, 15.7, 23.8 and 28.5 mg/L, respectively, corresponding to 152, 106, 82.6, 89.3, 76.0, 52.2 and 28.5% of the nominal concentrations.

- At the end of the test, measured concentrations of the test substance in the control, 0.88, 1.94, 4.27, 9.39, 20.7, 45.5 and 100 mg/L test media were 0, 1.10, 1.75, 3.58, 8.52, 17.8, 24.6 and 24.7 mg/L, respectively, corresponding to 82.1, 85.4, 101, 102, 113, 103 and 86.7% of the initial measured concentrations.

- Although the test concentrations were maintained within 80 -120% of the initial concentration, they were not within 80 -120% of nominal, thus the endpoints were expressed in terms of geometric mean measured concentrations.

- The overall mean measured concentrations of the test substance in the control, 0.88, 1.94, 4.27, 9.39, 20.7, 45.5 and 100 mg/L nominal concentrations were 0, 1.21, 1.89, 3.55, 8.45, 16.7, 24.2 and 26.5 mg/L, respectively.

Validity criteria fulfilled:
yes
Remarks:
see 'Overall remarks''.
Conclusions:
The 48-h EC50 is 14.3 mg/L in Daphnia magna.
Executive summary:

The acute toxicity to Daphnia magna was examined in a study performed in accordance with OECD TG 202, and in compliance with GLP criteria. Groups of 20 daphnids (4 replicates of 5 animals) were exposed to nominal test concentrations of 0 (control), 0.88, 1.94, 4.27, 9.39, 20.7, 45.5 and 100 mg/L for 48 hours under static conditions. Test substance analysis was performed at the start (t=0h) and at the end of exposure (t=48h) and geometric mean measured concentrations determined at 1.21, 1.89, 3.55, 8.45, 16.7, 24.2 and 26.5 mg/L. As measured test concentrations were not all within 80 -120% of nominal, results are expressed as measured concentrations. Daphnid immobility was recorded at 24 hours and 48 hours after start of exposure. The study validity criteria were met.

After 48 hours exposure to 1.21, 1.89, 3.55, 8.45, 16.7, 24.2 and 26.5 mg/L, daphnid immobility was 0, 0, 10, 0, 35, 95 and 100%, respectively. Based on these findings, the 48-h EC50 value was determined to be 14.3 mg/L (95% CI = 13.1 - 15.4 mg/L).

Description of key information

The acute toxicity of the substance to Daphnia magna was derived by read-across from an analogue with the same chemical core structure, which was examined for D. magna toxicity in a study performed in accordance with OECD TG 202, and in compliance with GLP criteria.

Groups of 20 daphnids (4 replicates of 5 test organisms) were exposed to nominal test concentrations of 0 (control), 0.88, 1.94, 4.27, 9.39, 20.7, 45.5 and 100 mg/L for 48 hours under static conditions. Test substance analysis was performed at the start (t = 0 h) and at the end of exposure (t = 48 h), by means of a sufficiently validated HPLC-UV method. Since measured test concentrations were not all within 80 -120% of nominal, results are expressed in terms of geometric mean measured concentrations, which were determined as 1.21, 1.89, 3.55, 8.45, 16.7, 24.2 and 26.5 mg/L.

Daphnid immobility was recorded at 24 hours and 48 hours after start of exposure. After 48 hours exposure to 1.21, 1.89, 3.55, 8.45, 16.7, 24.2 and 26.5 mg/L, daphnid immobility was 0, 0, 10, 0, 35, 95 and 100%, respectively. Based on these findings, the 48-h EC50 value was determined to be 14.3 mg/L (95% CI = 13.1 - 15.4 mg/L).

All study validity criteria were met.

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
14.3 mg/L

Additional information