2,6-dibromo-4-cyanophenyl heptanoate

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

Study period:

10 - 12 Nov, 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-2 (Aquatic Invertebrate Acute Toxicity Test)

Version / remarks:

1985

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

During the in-life phase of the definitive study, water samples were removed from both replicate test solutions of each treatment level and the controls at 0 and 48 hours of exposure for analysis of concentrations. Each exposure solution sample was collected from the approximate midpoint of the test vessel by pipette.

Vehicle:

yes

Remarks:

Acetone

Details on test solutions:

A 1.0 mg a.i./mL stock solution was prepared prior to test initiation and at 24 hours of exposure by diluting 0.1060 g test substance (0.1005 g as active ingredient) with acetone to a total volume of 100 mL. The resulting solutions were observed to be clear and colorless with no sign of undissolved test material.
The flow through system was calibrated to deliver 0.04536 mL/cycle of the stock solution (1.0 mg a.i./mL) into the diluter's chemical mixing chamber which also received 0.454 L dilution water per cycle. The solution contained in the mixing chamber constituted the highest nominal treatment level (100 µg a.i./L) and was subsequently diluted (60% dilution factor) to provide the remaining nominal test concentrations: 13, 22, 36 and 60 µg a.i./L. A similar system delivered the solvent control stock solution (0.44 mL/mL) to the solvent control vessels which contained the maximum amount of acetone present in any test concentration (0.10 mL/L)

Test organisms (species):

Daphnia magna

Details on test organisms:

The Daphnia magna used in this toxicity test were obtained from laboratory cultures maintained at Springborn Laboratories, Inc., Wareham, Massachusetts.
Daphnids were fed a combination of a trout food suspension and a unicellular green algae once daily prior to the test initiation. The food solution contained 5.0 mg/mL trout food and approximately 4 X 107cells/mL of algae.

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

160 - 170

Test temperature:

20 - 21 °C

pH:

8.0 - 8.3

Dissolved oxygen:

92 - 103 %

Conductivity:

500 - 550

Nominal and measured concentrations:

Nominal concentrations: 13, 22, 36, 60 and 100 µg a.i./L
Mean measured concentrations: 8.7, 15, 26, 44 and 81 µg a.i./L (67 - 81 % of the nominal)

Details on test conditions:

The test was initiated when 10 daphnids (less than 24 hours old) were impartially selected and introduced two at a time to each replicate exposure vessel until each replicate contained 10 daphnids.
Daphnids were not fed during the 48 hour definitive exposure.
The number of immobilized daphnids observed in each replicate test vessel was recorded at 24 and 48 hours during the exposure period. Daphnids were determined immobile if, after gentle prodding, no movement except for minor appendages was observed (i.e., absence of movement within the solution's water column). Biological observations (e.g., abnormal behavior or appearance of the test organisms) and observations of the physical characteristics of the test solutions (e.g. precipitate, film on the surface of the test solution) were also made and recorded at test initiation and at 24- and 48-hours of exposure. Daphnids were not fed during the 48 hour definitive exposure.

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

31 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Remarks on result:

other: 95 % C.I.: 25 - 40 µg a.i./L

Details on results:

Following 48 hours of exposure, 60 % and 95 % immobilization was observed among daphnids exposed to the 44 and 81 µg a.i./L treatment levels, respectively, while 30 % immobilization was recorded in the 15 and 26 µg a.i./L treatment levels. Sublethal effects were observed among several of the mobile daphnids exposed to the 15 µg a.i./L treatment level and all of the mobile daphnids exposed to the 26, 44 and 81 µg a.i./L treatment levels. A total of 5 % immobilization was recorded among daphnids exposed to the lowest treatment level. In addition, two of the mobile daphnids exposed to this treatment level were observed to be lethargic at test termination. It should be noted however, that the observations of immobilization and sublethal effects were isolated to one replicate (B) of this exposure level. Since all of the daphnids in replicate A of the 8.7 µg a.i./L treatment level were observed to be mobile and normal in behavior and appearance, the effects observed in replicate B are not considered to be an adverse response to the toxicity of test substance.

Please refer to "overall remark/ attached background material" field for result tables.

Validity criteria fulfilled:

not specified

Conclusions:

The present guideline study was conducted in compliance with GLP. Under the test conditions used, the EC50 48h for Daphnia magna was 0.031 mg a.i./L.

Description of key information

From short-term key study, the 48-hour EC50 for aquatic invertebrates exposed to the present test material was 0.031 mg a.i./L in freshwater.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

ca. 0.031 mg/L

Additional information

One GLP-study is available for short-term toxicity testing to aquatic invertebrates and was identified as key study.

In the key study (1993), the acute toxicity of test substance to daphnia was investigated in a 48-hours test with Daphnia magna according to US EPA-72.2 guidelines.Ten daphnids per replicate and two replicate per concentration were exposed for 48 hours under flow-through conditions to nominal concentrations of 13, 22, 36, 60 and 100 µg a.i./L, alongside with a control and a solvent control. Mean measured concentrations ranged from 67 to 81 % of nominal concentrations. Based on the mean measured concentrations, the 48-hour EC₅₀ resulted in 0.031 mg a.i./L.