Decanoic acid, mixed diesters with octanoic acid and triethylene glycol

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:

July 12, 1995 to December 14, 1995

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)

Version / remarks:

Adapted 17 July 1992

Deviations:

yes

Remarks:

Temperature (daphnid culture) outside the prescribed range on 1 day of acclimation. This had no affect on the outcome of the test and no other deviations noted. The daphnia culture production of at least 3 young per adult daphnid cannot be verified.

Qualifier:

according to guideline

Guideline:

other: U.S. EPA 40 CFR Part 797

Version / remarks:

1993. Toxic Substances Control Act Test Guidelines; Final Rules

Deviations:

yes

Remarks:

As previously noted

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

The sample of test substance (T.R. Wilbury Laboratories sample number 510) used for the toxicity test was delivered on June 27, 1995. It was contained in a 300 ml glass bottle that was shipped at ambient temperature. The label attached to the container included the following information: "Prod: 414, Batch # 024910, Date: 7-19-95, Time: 8:30 am, Remarks: Drum Sample"..

The test substance (a thin yellow liquid) was supplied by C.P. Hall Company 7300 south central Ave, P.O. Box 608, Bedford Park, Illinois 60499-0608. Prior to use the test substance was stored at room temperature in the dark and unused test substance is returned to the sponsor. The test substance was assumed to be 100% active ingredient and to be stable under test conditions.

Analytical monitoring:

no

Remarks:

Water accomodated fractions (WAF) used

Vehicle:

no

Details on test solutions:

For the definitive test, two 1,000 mg/L WAFs were prepared at the beginning of the test by combining the appropriate amount of test substance and dilution water in a mixing vessel equipped with a magnetic stirrer. The mixture was stirred for 24 hours and the two mixtures were allowed to settle for approximately 1 hour. During mixing the vortex extended from the surface approximately 25% of the way to the bottom of the mixing vessel. Following the settling period the water phase containing the WAF was removed from each mixing vessel with a siphon and the two WAFs were combined.

Test organisms (species):

Daphnia magna

Details on test organisms:

Juvenile daphnids, Daphnia magna, employed as test organisms were from a single source. The culture that produced the daphnids produced young before day 12. The daphnids were produced from an in-house culture and identified using an appropriate taxonomic key. The original parental culture was procured from Aquatic Research Organisms, Hampton, New Hampshire on June 1, 1994. Prior to testing the daphnid culture was maintained in dilution water under static, renewal conditions in a 4 liter glass jar. Daphnids used for the test were less than 24 hours old. Daphnid cultures were supplied with the freshwater alga, Selenastrum capricornutum, and/or a yeast/trout chow mixture daily throughout the acclimation period and no mortality was observed during the 48 hours preceding the start of the toxicity test.

During acclimation daphnids were not treated for disease and they were free of apparent sickness, injuries, and abnormalities at the beginning of the test. During the 14 day period before the start of the test the culture temperature was 20.7 to 21.0°C and the dissolved oxygen concentration was always at least 7.8 mg/L.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

The hardness was 160 mg/L as CaCO3

Test temperature:

The mean temperature was 20.2°c (range = 19.8 to 20.8°C)

pH:

The pH ranged from 7.8 to 8.3

Dissolved oxygen:

The mean dissolved oxygen concentration during the definitive test was 8.4 mg/L (range = 7.4 to 9.0 mg/L).

Salinity:

N/A

Conductivity:

The mean conductivity was 600 umhos/cm (range = 560 to 610 umhos/cm)

Nominal and measured concentrations:

N/A

Details on test conditions:

The test was conducted under static conditions at a target temperature of 20 ± 1°C. Ten daphnids were indiscriminately distributed to each of 2 replicates of the control, 130, 220, 360, 600, and the 1,000 mg/L wAF. The test was performed in 300 ml glass vessels that contained 250 ml of test solution (water depth was approximately 9 cm). The loading rate was 0.31 g/L.

Test vessels were randomly arranged in an incubator during the test (a random numbers table was used to select the location of each vessel). A 16 hour light and 8 hour dark photoperiod was automatically maintained with cool-white fluorescent lights that provided a light intensity of =6 uEin/m2sec with a 15 minute transition period between dark and light. Aeration was not required to maintain dissolved oxygen concentrations above acceptable levels. Daphnids were not fed during the test.

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

550 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other:

Remarks:

The 95% confidence interval = 360 to 1000 mg/L

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

440 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other:

Remarks:

The 95% confidence interval = 360 to 600 mg/L

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

360 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

One hundred percent survival occurred in all control vessels and no sublethal effects were noted in the control during the test. Mortality results are summarized in the table.

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

Standard statistical techniques (Stephan, 1983) were used to calculate EC50 values. The binomial/nonlinear interpolation method was used with 24 hour data and the moving average method was used with 48 hour data. The NOEC is the highest concentration that did not cause toxicant related effects (survival was at least 90% and no sublethal effects were noted).

Stephan, C.E. 1983. Computer methods for the calculation of LC50 values. Personal communication.

Survival and sublethal effects of the test material on Daphnia magna

Nominal Conc. of the WAF	Rep	Number Survivors			Number Affected
(mg/L)		0 hr	24 hr	48 hr		0 hr	24 hr	48 hr
0 (control)	1	10	10	10		0	0	0
	2	10	10	10		0	0	0
130	1	10	10	10		0	0	0
	2	10	10	10		0	0	0
220	1	10	10	10		0	0	0
	2	10	9	9		0	0	0
360	1	10	10	9		0	0	0
	2	10	10	9		0	0	0
600	1	10	10	0		0	7	0
	2	10	10	0		0	6	0
1000	1	10	10	0		0	7	0
	2	10	10	0		0	7	0
Note: Affected daphnids were lethargic. One daphnid exposed to the 600 mg/L WAF was floating at 24 hours. Floating is not considered a sublethal effect.

 

Validity criteria fulfilled:

not specified

Conclusions:

The 24 hour median effective concentration (EC50) of the test substance to daphnids is 550 mg/L (expressed as the nominal amount of test substance used to prepare the WAF) and the 48 hour EC50 is 440 mg/L (95% confidence interval of 360 to 600) The 48 hour no observed effect concentration is (NOEC) is 360 mg/L.

Executive summary:

The acute toxicity of the water accommodated fraction (WAF) of a 1,000 mg/L mixture of the test substance and water to the daphnid, Daphnia magna, was investigated during a study conducted at T.R. Wilbury Laboratories, Inc. The test, which was designed to determine the toxicity of the WAF of the test substance, was performed from August 2 to 4, 1995.

The test was performed at 20 ± 1°C under static conditions. The dilution water was carbon filtered deionized water collected at Marblehead, Massachusetts and adjusted to a hardness of 160 mg/L as CaCO3. Juvenile daphnids, <24 hours old, used for the test were from a laboratory culture that was acclimated to test conditions for at least 14 days prior to use in the test.

The 24 hour median effective concentration (EC50) of the test substance to daphnids is 550 mg/L (expressed as the nominal amount of test substance used to prepare the WAF) and the 48 hour EC50 is 440 mg/L (95% confidence interval of 360 to 600) The 48 hour no observed effect concentration is (NOEC) is 360 mg/L.

Description of key information

In a key study with the test substance, the 24 hour median effective concentration (EC50) of the test substance to daphnids was 550 mg/L (expressed as the nominal amount of test substance used to prepare water accomodated fractions) and the 48 hour EC 50 is 440 mg/L (95% confidence interval of 360 to 600) The 48 hour no observed effect concentration is (NOEC) is 360 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

440 mg/L

Additional information

The test substance is a member of a category of aliphatic esters submitted by The American Chemistry Council's (ACC) Aliphatic Esters Panel (Panel) under the High Production Volume (HPV) Chemical Challenge Program (ACC, 2003). Information from a Screening Information Data Set (SIDS) developed in that program serves as supplementary or weight-of-evidence in the current dossier. Category ester compounds with similar structures and functionalities were generally of minimal or low acute toxicity to Dapnia magna at or above the effective water solubility limits of the substances. The structurally similar material, 3,6,9-Trioxaundecamethylene bis(2-ethylhexanoate) (CAS 18268 -70 -7), had an estimated 48-hour EC50 for the water soluble fraction (WSF) of 140 mg/L. The test material 2,2'-ethylenedioxydiethyl bis(2 -ethylhexanoate) (CAS 94 -28 -0) caused no immobilization of daphnids in 96 h at the nomial test concentration of 97 mg/L. Ethane-1,2 -diylbis(oxyethane-2,1 -diyl) bisheptanoate (CAS 7434 -40 -4) had a stated 48-h EC50 value in excess of 9.1 mg/L, displaying some minimal toxicity. Heptanoic acid, oxybis(2,1 -ethanediyloxy-2,1 -ethanediyl)ester (CAS 70729 -68 -9) had an estimated 24-h EC50 of 3800 mg/L, well above the solubility limit of the substance. Heptanoic acid, ester with 2,2,4 -trimethyl-1,3 -pentanediol (CAS 71839 -38 -8) had a 48 -h EC50 in excess of 2000 mg/L, well above the water solubility limit of the test substance.