Dibutyl terephthalate

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyl terephthalate

EC Number:

217-803-9

EC Name:

Dibutyl terephthalate

Cas Number:

1962-75-0

Molecular formula:

C16H22O4

IUPAC Name:

1,4-dibutyl benzene-1,4-dicarboxylate

Details on test material:

- Name of test material (as cited in study report): Dibutyl terephthalate
- Substance type: production sample
- Physical state: clear liquid
- Analytical purity: 98.7%
- Purity test date: November 30, 2004
- Lot/batch No.: X-29455-010

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples of the control and test substance exposure solutions were analyzed at test start and test end to verify test substance concentration. The samples analyzed at test start and test end were collected from approximately mid-depth of the test vessels using a spigot-valve assembly. Samples were analyzed using gas chromatography with flame ionization detection (GC/FID). The physical parameters of the exposure solutions were measured at test start and at the end of each 24-hour period. The appearances of the exposure solutions were observed and recorded at test start, after 4 hours of exposure and at the end of each 24-hour period. The test organisms were observed for behavioral abnonnalities at test start, after 4 hours of exposure and at the end of each 24-hour period.

Test solutions

Vehicle:

yes

Details on test solutions:

The solubility of the substance in the test medium was measured by the analytical laboratory. The solubility of the substance was detennined to be 0.13 mg/L. Exposure solutions containing the substance at nominal concentrations of 1 mg/L were tested. The exposure solutions were prepared by direct addition of a stock solution containing the substance to the dilution water. The stock solution was prepared at a nominal concentration of 10 mg/mL by weighing appropriately 255.8 mg of substance into a 25-mL volumetric flask that was brought to volume with a solvent, N,N-Dimethylformamide (DMF). The stock was sonicated and inverted several times to dissolve the substance then 2 mL was added to 22-L vessels containing 20 liters of laboratory dilution water. Dilution water and carrier solvent control solutions were also prepared. Carrier solvent controls were prepared by pipetting 2 mL of DMF into 20 liters of laboratory dilution water. The solutions were stirred with stir bars and stir plates for approximately 3 hours. While stirring the physical parameters of the solutions were measured and 250-mL aliquots were removed from each 22-L vessel and submitted for concentration verification.

Test organisms

Test organisms (species):

Pimephales promelas

Details on test organisms:

The test organisms were obtained from Aquatic BioSystems, Inc., 1300 Blue Spruce Drive, Suite C, Fort Collins, CO and designated Lot# 070804ABS. They were hatched July 8-12, 2004 and received in the laboratory on Septembcr 9, 2004. The organisms used in this test were cultured in laboratory dilution water for at least two weeks under test conditions. The average weekly temperature and dissolved oxygen concentration of the culture water was 20.0C and 9.6 mg/L, respectively, during the acclimation prior to the test. The minnows were not fed 24 hours prior to exposure to the solutions. The minnows were collected by gently netting them from the rearing tanks into small glass bowls filled with culture water. Sequential randomization was accomplished by allocating to each small glass bowl no more than 50% of any one set of test organisms at a time. The organisms were then placed into the test vessels by gently pouring the contents of the small glass bowls through a net and inverting the net over the test solution. Two additional sets of ten minnows were sacrificed at the start of the test and measured to determine average wet weight and mean standard length representative of the exposed population. The average wet weight per minnow for set #1 and set #2 were 0.23 and 0.25 g, respectively. The mean standard lengths for set #1 and set #2 were 2.4 and 2.5 cm, respectively.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test conditions

Test temperature:

The temperature of the dilution water and carrier solvent control solutions ranged from 19.6 to 20.4°C. The temperature of the test substance
solutions ranged from 19.9 to 20.4C.

pH:

The pH of the control solutions and test substance solutions ranged from 7.8 to 8.3.

Dissolved oxygen:

The dissolved oxygen concentrations of the control solutions ranged from 6.7 to 9.2 mg/L. The dissolved oxygen concentrations of the test substance solutions ranged from 6.8 to 9.2 mg/L

Nominal and measured concentrations:

The individual 96-hour replicate concentrations of the nominally prepared 1 mg/L exposure replicates were calculated to be 0.19 mg/L and 0.15 mg/L. The individual replicate solutions exhibited 94.9% and 96.6% loss of test substance concentration during the 96-hour exposure.
The combined replicate exposure concentration was calculated to be 0.17 mg/L.
used to estimate endpoint values.

Details on test conditions:

The water used to culture the test organisms and prepare the test substance exposure solutions is pumped from Lake Ontario and treated by the Kodak Park Lake Station Water Treatment Facility. The treated water is then stored in a large underground reservoir located near the testing facility. This water is subsequently pumped into the laboratory where it passes through a set of polypropylene filters, a series of activated carbon filters, through another set of polypropylene filters, and finally treated with sodium thiosulfate via a chemical injection system to eliminate trace levels of residual chlorine. The water is then tempered to 20 ± 2°C by passage through a heat-exchange unit before being distributed throughout the testing facility through stainless steel and PVC piping. The Environmental Analytical Services (EAS) group of Eastman Kodak Company monitors the quality of the filtered-treated-tempered water twice a year. This characterization is documented and archived in a central file maintained by the Ecotoxicology Group. The filtered-treated-tempered water contains no contaminants at concentrations that could intetfere with the outcome of study or the culturing of the test
organisms.The limit test was performed as a 96-hour, static exposure. The exposure solutions were maintained at a temperature of 20 ± 1°C and illuminated with fluorescent lighting for 16 hours followed by a 30-minute transition period leading to 8 hours of darkness. The test vessels were 22-L pyrex cuboidal glass tanks containing 20 L of test solution with approximately 2700 cubic centimeters of headspace. The test chambers were covered during the study. They were not cleaned or aerated, nor were the test organisms fed. Two replicates were prepared for each exposure. Ten test organisms were introduced into each replicate. At test start the exposure solutions were prepared, the physical parameters of the solutions were measured
and ten test organisms were introduced into eaeh replicate test vessel. Observations for mobility, stress, and solution appearance were perfonned at test start, after 4 hours and at the end of each 24 hour period. The physical parameters of each exposure solution were measured after each 24 hour interval.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0.17 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 0.17 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

The test organisms were observed for behavioral abnonnalities at test start, after 4 hours of exposure, and at the end of each 24-hour period. No mortality or behavioral effects were observed in the control or test substance exposures during the study.

Reported statistics and error estimates:

Statistical analyses of the data were not perfonned due to the lack of observed effects.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 96-hour LC50 value was estimated to be >0.17 mg/L (the highest tested concentration). The NOEC was determined to be > or = 0.17 mg/L. The results of this study indicate that the 96-hour LC50 and NOEC values for the test substance are greater than the measured aqueous solubility.

Executive summary:

Juvenile fathead minnows, Pimephales promelas, were exposed to one concentration of the test substance in a 96-hour, static, aquatic effects limit test. The solubility of the substance in the test medium was investigated and determined to be 0.13 mg/L. Exposure solutions containing the substance at nominal concentrations of 1 mg/L were tested. The concentration of test substance in the exposure solutions were analytically verified during the study. The average concentration of the prepared solutions over the course of the study was calculated to be 0.17 mg/L. The test organisms were observed for behavioral abnormalities at test start, after 4 hours of exposure, and at the end of each 24-hour period. No mortality or behavioral effects were observed in the control or test substance exposures during the study. The 96-hour LC50 value was estimated to be >0.17 mg/L (the highest tested concentration). The NOEC was determined to be > or = 0.17 mg/L. The results of this study indicate that the 96-hour LC50 and NOEC values for the test substance are greater than the measured aqueous solubility.