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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
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 (incl. certificate)
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: PX708164
- Expiration date of the lot/batch: 30 June 2018 (expiry date)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature container flushed with nitrogen
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The batch of Setalux 7002 BX-55 tested was a clear dark yellow viscous liquid mixture of different components and not completely soluble in test medium at the loading rates initially prepared. No correction was made for the purity/composition of the test item.
Preparation of test solutions started with loading rates individually prepared ranging between 0.10 and 100 mg/L. The test item was weighed on watch glasses which were added to the medium. A 7 - 8 hour period of magnetic stirring was applied to ensure maximum dissolution of the test item in medium. The obtained mixtures were allowed to settle overnight. Thereafter, the aqueous Water Accommodated Fractions (WAFs) were collected by siphoning through glass wool and used as test concentrations. All test solutions were clear and colorless at the end of the preparation procedure except for the highest loading rate of the combined limit/range-finding test and range-finding test which were hazy to slightly hazy, respectively.
Any residual volumes were discarded.
Test organisms (species):
Daphnia magna
Details on test organisms:
In-house laboratory culture with a known history. Daphnids originated from a healthy stock, 2nd to 5th brood, showing no signs of stress such as mortality >20%, presence of males, ephippia or discoloured animals and there was no delay in the production of the first brood.
For the test selection of young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.

With newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel. Maximum age of the cultures was 4 weeks After 7 days of cultivation half of the medium was renewed twice a
week. Temperature of medium 18-22°C Feeding took place daily with a suspension of fresh water algae. M7 is used as medium, as prescribed by Dr. Elendt-Schneider (Elendt, B.-P., 1990: Selenium deficiency in Crustacea. An ultrastructural approach to antennal damage in Daphnia magna Straus. Protoplasma 154, 25-33).
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
180 mg/L expressed as CaCO3
Test temperature:
Between 19 and 20°C throughout test period
pH:
7±0.1
Dissolved oxygen:
8.5±0.35
Nominal and measured concentrations:
0.46, 1.0, 2.2, 4.6 and 10 WAF loading rate (mg/L)
Details on test conditions:
TEST SYSTEM
- Test vessel: 50 mL
- Type: closed airtight
- Material, size, headspace, fill volume: all-glasscontaining 50 mL of test solution
- 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: M7, as prescribed by Dr. Elendt-Schneider
- Culture medium different from test medium: no
- Intervals of water quality measurement: pH and dissolved oxygen At the beginning and at the end of the test, for all loading rates and the control. Temperature of medium Continuously in a temperature control vessel, beginning at the start of the test.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours photoperiod daily

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobility (including mortality) at 24 hours and at 48 hours.

VEHICLE CONTROL PERFORMED: no

RANGE-FINDING STUDY
- Test concentrations: Ten daphnids per loading rate (in duplicate, 5 per vessel) were exposed to WAFs prepared at loading rates of 0.10, 1.0 and 10 mg/L and to a control.
- Results used to determine the conditions for the definitive study: At the end of the test, 10 and 100% immobility was observed at loading rates of 1.0 and 10 mg/L, respectively. Therefore, the expected EL50 was between 1.0 and 10 mg/L.
Reference substance (positive control):
yes
Remarks:
K2Cr2O7 (Potassium dichromate)
Key result
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
1.5 mg/L
Nominal / measured:
nominal
Conc. based on:
other: Water Accommodated Fractions (WAFs)
Basis for effect:
mobility
Details on results:
No immobility was observed at the lowest loading rate during the test period. At the end of the test, 5% immobility was observed at a loading rate of 1.0 mg/L and 100% immobility was observed at the three highest loading rates. The responses recorded in this test allowed for reliable determination of an EL50.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: 0.10, 0.18, 0.32, 0.56, 1.0 and 1.8 mg/L and to a control
- Limit test: no
- Dose-response test: The actual responses in this reference test with K2Cr2O7 are within the ranges of the expected responses at the different concentrations, i.e. the 48h-EC50 was between 0.3 and 1.0 mg/L. Hence, the sensitivity of this batch of D. magna was in agreement with the historical data collected at Charles River Den Bosch.
- 48-h EC50: 0.33 mg/L with a 95% confidence interval between 0.29 and 0.38 mg/L.

Time (h)

Replicate

Setalux 7002 BX-55; WAF loading rate (mg/L)

0

 

Control

0.46

1.0

2.2

4.6

10

 

A

5

5

5

5

5

5

 

B

5

5

5

5

5

5

 

C

5

5

5

5

5

5

 

D

5

5

5

5

5

5

 

Total introduced

20

20

20

20

20

20

24

A

0

0

0

4

1

5

 

B

0

0

0

3

4

5

 

C

0

0

0

4

4

5

 

D

0

0

0

4

4

5

 

Total immobilized

0

0

0

15

13

20

 

% Effect

0

0

0

75

65

100

48

A

0

0

0

5*

5

5

 

B

0

0

1

5

5

5

 

C

0

0

0

5

5

5

 

D

0

0

0

5

5

5

 

Total immobilized

0

0

1

20

20

20

 

% Effect

0

0

5

100

100

100

*Microscopic observation revealed no test item attached to the daphnids.

Validity criteria fulfilled:
yes
Conclusions:
The 48h-EL50 for Daphnia magna exposed to Setalux 7002 BX-55 was 1.5 mg/L based on loading rates (95% confidence interval between 0.84 and 2.5 mg/L).
Executive summary:

No immobility was observed at the lowest loading rate during the test period. At the end of the test, 5% immobility was observed at a loading rate of 1.0 mg/L and 100% immobility was observed at the three highest loading rates. The responses recorded in this test allowed for reliable determination of an EL50. In conclusion, the 48h-EL50 for Daphnia magna exposed to Setalux 7002 BX-55 was 1.5 mg/L based on loading rates (95% confidence interval between 0.84 and 2.5 mg/L).

Description of key information

The objective of the study was to evaluate Setalux 7002 BX-55 for its ability to generate acute toxic effects on the mobility of Daphnia magna during an exposure period of 48 hours and, if possible, to determine the EL50 at 24 and 48 hours of exposure.

The study procedures described in this report were based on the OECD guideline No. 202, 2004. In addition, procedures were based on the test methods described in the OECD series on testing and assessment number 23, 2000.

The batch of Setalux 7002 BX-55 tested was a clear dark yellow viscous liquid mixture of different components and not completely soluble in test medium at the loading rates initially prepared. Water Accommodated Fractions (WAFs) were individually prepared. A final test was performed based on a preceding combined limit/range-finding and rangefinding test. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to WAFs prepared at loading rates of 0.46, 1.0, 2.2, 4.6 and 10 mg/L. The total exposure period was 48 hours.

No immobility was observed at the lowest loading rate during the test period. At the end of the test, 5% immobility was observed at a loading rate of 1.0 mg/L and 100% immobility was observed at the three highest loading rates.

The project did not include sampling for determination of actual exposure concentrations because no analytical method could be developed for this complex UVCB. However, the biological results indicate the daphnids were exposed to the test item. Consequently, results are reported based on loading rates.

The study met the acceptability criteria prescribed by the study plan and was considered

valid.

In conclusion, the 48h-EL50 for Daphnia magna exposed to Setalux 7002 BX-55 was 1.5 mg/L based on loading rates (95% confidence interval between 0.84 and 2.5 mg/L).

Key value for chemical safety assessment

EC50/LC50 for freshwater invertebrates:
1.5 mg/L

Additional information