5-bromo-1,3-dichloro-2-fluorobenzene

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

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

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Duplicate samples from the freshly prepared test media of all test concentrations and the control were taken at the start of the test and at day 1.
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 aged test media of all test concentrations and the control were collected at day 1 (after 24 hours of exposure) and at the end of the test by pooling the contents of the test beakers of each treatment.
All samples remained undiluted.

Vehicle:

no

Details on test solutions:

A defined amount of the test item was added directly to the test water for each test concentration and was carefully stirred for 48 hours in the dark to dissolve as much of the test item as possible. A supersaturated stock solution of 100 mg test item/L was prepared by mixing 240.5 and 240.1 mg test item into 2405 and 2401 mL test water. After cessation of mixing and a following period (1 hour) of settling to allow phase separation, the aqueous phase, i.e. the water accommodated fraction, was drawn off carefully and adequate volumes of this water accommodated fraction were mixed into test water to obtain the desired dilutions of 1:2, 1:4, 1:8 and 1:16. The test media were prepared just before the introduction of the daphnids.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: Straus, clone 5
- Age at study initiation (mean and range, SD): from 2.25 to 19.5 hours old
- Method of breeding: 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 the same reconstituted water as the test water used in the test (see 3.2.4). 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.
- Source: in-house
- Feeding during test : no

ACCLIMATION
Not required, as the test was performed in the same medium as the culturing

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.5 mmol/L as CaCO3

Test temperature:

20.3 to 20.8 °C in freshly prepared media
20.3 to 20.6 °C in aged media

pH:

8.2 to 8.3 in freshly prepared media$
7.9 to 8.0 in aged media

Dissolved oxygen:

8.8 to 9.5 mg/L in freshly prepared media
8.7 to 8.9 mg/L in aged media

Salinity:

0.9 mmol/L

Conductivity:

not reported

Nominal and measured concentrations:

Nominal concentrations:
100 mg/L weight accommodated fraction stock solution, 1:2 dilution, 1:4 dilution, 1:8 dilution, 1:16 dilution, control
Measured geometric mean concentrations:
2.97 mg/L for the 100 mg/L weight accommodated fraction (WAF) stock solution
1.40 mg/L for the 1:2 dilution of the WAF stock solution
0.725 mg/L for the 1:4 dilution of the WAF stock solution
0.373 mg/L for the 1:8 dilution of the WAF stock solution
0.216 mg/L for the 1:16 dilution of the WAF stock solution

Details on test conditions:

TEST SYSTEM
- Test vessel: all
- Type: covered with a lid
- Material, size, headspace, fill volume: 100 mL glass beakers, containing about 60 mL test medium
- Aeration: no
- Renewal rate of test solution: test medium was renewed after 24 hours
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): not required

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water (Elendt M4)
- Alkalinity: 0.9 mmol/L
- Hardness: 250 mg/L as CaCO3
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: constant light
- Light intensity: 553 lux (ranging from 300 to 870 lux)

EFFECT PARAMETERS MEASURED: immobility

VEHICLE CONTROL PERFORMED: not required, as no vehicle was used

RANGE-FINDING STUDY
- Test concentrations: water accommodated fractions with nominal loadings of 6.25, 12.5, 25, 50 and 100 mg/L and a control were tested
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate tested at least twice a year

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.54 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat. (dissolved fraction)

Basis for effect:

mobility

Remarks on result:

other: 95% confidence interval: 1.45 - 1.66 mg/L

Results with reference substance (positive control):

In the most recent test with the reference item potassium dichromate performed in January 2018 (study code 88299220), the EC50 after 24 hours was determined to be 1.06 mg test item/L, indicating 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).

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC50 value determined in this study was 1.54 mg/L, with a 95% confidence interval ranging from 1.45 to 1.66 mg/L.

Executive summary:

A study on the acute toxicity of the substance to aquatic invertebrates (Daphnia magna) was carried out in accordance with OECD TG 202 under GLP. The test was conducted over a period of 48 hours with reconstituted water (Elendt M4 medium) under semi-static conditions with renewal of test medium after 24 hours. All tests were conducted in 100 mL glass beakers containing 60 mL of test medium. The beakers were covered with a lid during the tests. Test solutions were prepared from an oversaturated stock solution of 100 mg/L, which was used undiluted and in 1:2, 1:4, 1:8 and 1:16 dilutions. Furthermore, an unexposed control was included in the test. The test concentrations were confirmed with a suitable analytical method applying GC-MS/MS. The geometric mean measured concentrations were 2.97, 1.40, 0.725, 0.373 and 0.216 mg/L for the 100 mg/L weight accomodated fraction stock solution and the dilutions, respectively. The water temperature was between 20.3 and 20.8 °C in freshly prepared medium and between 20.3 and 20.6 °C in aged medium. The pH value ranged from 8.2 to 8.3 in freshly prepared medium and from 7.9 to 8.0 in aged medium. The dissolved oxygen concentration was between 8.8 and 9.5 mg/L in freshly prepared medium and between 8.7 and 8.9 mg/L in aged medium.

Four replicates with five female young daphnids (less than 24 hours old) each were run for each test concentration and the control. The adverse effects of the test substance were evaluated by observing the mobility of the daphnids in each test vessel. No immobilised daphnids were observed after 48 hours in the test vessels with 0.725 mg/L or less. In the vessels with a test concentration of 1.40 mg/L, two immobilised daphnids were observed after 48 hours, and at the highest test concentration of 2.97 mg/L, all daphnids were immobilised after 48 hours.

The validity criteria were met as the immobilisation rate in the control was 0% and the dissolved oxygen concentration was >3 mg/L at all times during the study (>8.7 mg/L in the control and test vessels at the end of the test).

Description of key information

48-hour EC50 = 1.54 mg/L in water flea (Daphnia magna), semi-static (GLP, OECD TG 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.54 mg/L