N,N-dimethyl-3-(octadecyloxy)propylamine

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From January 11, 2010 to March 2, 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N-dimethyl-3-(octadecyloxy)propylamine

EC Number:

241-516-8

EC Name:

N,N-dimethyl-3-(octadecyloxy)propylamine

Cas Number:

17517-01-0

Molecular formula:

C23H49NO

IUPAC Name:

dimethyl[3-(octadecyloxy)propyl]amine

impurity 1

Reference substance name:

Unknown impurities

IUPAC Name:

Unknown impurities

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

For the determination of the actual test item concentrations, duplicates samples were taken at the start and end of each test medium renewal period. For the 48-hour stability samples, the contents of the respective replicates were combined prior to sampling.

Immediately after sampling, methanol (1 mL methanol per 1-mL sample volume) was added to each sample to stabilize the latter during the storage period. Thereafter, all samples were deep-frozen (at about -20° C).

Test solutions

Vehicle:

no

Details on test solutions:

Reconstituted test water according to ISO 6341was used in the study. It consisted of analytical grade salts dissolved in purified water.

The ratio of Ca:Mg and Na:K was 4:1 and 10:1, respectively, based on molarity.

The test water was aerated prior to the start of the study until oxygen saturation was reached. During the test period, the test water was not aerated.

The following concentrations were tested: dilutions 1:10000, 1:3200, 1:1000, 1:320, 1:100 and 1:32 of a supersaturated stock dispersion with a loading rate of 100 mg/L. Additionally, a control (test Water without test item) was tested in parallel.

Due to the low water solubility of the test item, a dispersion with the loading rate of 100 mg/L was prepared by dispersing 100 mg of the test item (effective weights:100.5 and 100.4 mg for the first and second test medium renewal periods, respectively) in 1000 mL of test water. The dispersion was supported by ultrasonic treatment for 15 minutes and intense stirring by a magnetic stirrer over 96 hours at room temperature in the dark.

The long stirring period of 96 hours was selected according to the results of a pre-experiment (non-GLP) which showed that the maximum concentration of test item was reached after the stirring period of 96 hours.

After the 96-hour stirring period, the supersaturated dispersion of the test item was filtered at first through a Whatman GF/C filter (pore size 1.2 μm), and then through a Whatman GF/F filter (pore size 0.7 μm).Thus, a two-step filtration method was used to separate dissolved and dissolved test item. The negative pressure of the filtration unit was reduced as far as possible. The undiluted filtrate was serially diluted with test water to preparer the test media of all test concentrations. The test media were prepared just before introduction of the daphnids (i.e., start of the test and before the medium renewal) and were filled into equilibrated test vessels.

An equilibration of the test vessels was performed to secure a correct dosage, since in the range-finding tests and pre-experiment to the dosage of the test item, a considerable reduction of the actual test item concentrations in the test media was observed (due to a high adsorption of the test item to the test beakers). Thus, all the beakers prepared were filled with the test medium of the highest test concentration (dilution 1:32) for about 3 hours. After the 3-hour equilibration (immediately before addition of daphnids), the equilibrating medium in each test beaker was replaced with an appropriate freshly prepared test medium.

The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixtures, 2000.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The study was performed with young daphnids of the species Daphnia Magna Straus. A clone of this species (defined by the supplier as clone 5) was originally supplied by the University of Sheffield/ UK in 1992. Since that time, the clone has been bred at Harlan Laboratories in reconstituted water of the quality identical to the water quality used in the tests (in respect to pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests.

During breeding, daphnids are generally fed three times a week with an algal suspension of the green algae Scenedesmus subspicatus CHODAT, Strain No. 86.81 SAG, supplied by the Collection of Algal Cultures and cultivated at Harlan Laboratories under standardized conditions or a mixture of this algal suspension and a commercial fish diet.

At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L as CaCO3

Test temperature:

20ºC

pH:

7.8-8.0

Dissolved oxygen:

8.4 mg/L

Nominal and measured concentrations:

Dilution: 1:10000, 1:3200, 1:1000. 1:320, 1:100, 1:32.
Mean measured concentration (µg/L): (n.a.), 2.2, 7.0, 25, 95, 509.

Details on test conditions:

For each treatment, 20 daphnids were used divided into four replicates of five daphnids each. The volume of test solution provided for each daphnia was 10 mL. Thus, the requirement of the test guidelines for the minimum volume of 2 mL test medium per daphnia was fulfilled. The daphnids were randomly distributed to the test vessels at initiation of the test.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

9.8 µg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

After 48 hours of exposure, no immobilized test organisms were determined in the control and up to and including the mean measured concentration of 2.2 µg/L. At the next two higher mean measured concentrations of 7.0 and 25 µg/L, the immobilization rate increased to 45 and 95% respectively.

No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration.

The test is considered to be valid, as in the control, not more than 10% of the daphnids should show immobilization or other signs of disease or stress (e.g., discoloration or unusual behavior such as trapping at the surface water). Furthermore, the dissolved concentration at the end of the test was equal to or greater than 3 mg/L in the control and test vessels.

Results with reference substance (positive control):

For evaluation of the quality of the daphnia clone and the experimental conditions, potassium dichromate is tested as a positive control twice a year. The result of the latest positive control test in September 2009 (48-hour EC50: 1.1 mg/L, study C63680) indicated that the sensitivity of the test organisms was within the internal historical range (48-hour EC50 from 1996 to 2009: 0.53-1.1 mg/L).

Any other information on results incl. tables

Effect of the test substance on the Mobility of Daphnia magna

Dilution (loading rate: 100 mg/L)	Mean measured concentration (µg/L)	No. of Daphnids tested	Immobilized daphnids after 24 hours No.	Immobilized daphnids after 24 hours %	Immobilized daphnids after 48 hours No.	Immobilized daphnids after 48 hours %
Control	-	20	0	0	0	0
1: 10000	n.a	20	0	0	0	0
1:3200	2.2	20	0	0	0	0
1:1000	7.0	20	8	40	9	45
1:320	25	20	9	45	19	95
1:100	95	20	20	100	20	100
1:32	509	20	20	100	20	100

 

pH Values in the Treatments

Dilution (loading rate: 100 mg/L)	Exposure time 0h NEW	Exposure time 24 h OLD	Exposure time 24 h  NEW	Exposure time 48 h   OLD
Control	7.8	7.9	7.9	7.9
1:10000	7.8	7.9	7.9	7.9
1:3200	7.8	7.9	7.9	7.9
1:1000	7.8	7.9	7.9	8.0
1:320	7.8	8.0	7.9	8.0
1:100	7.9	8.0	7.9	8.0
1:32	7.9	8.0	7.9	8.0

Dissolved Oxygen Concentrations (mg/L) in the Treatments

Dilution loading rate: 100 mg/L	Exposure time 0h NEW	Exposure time 24h OLD	Exposure time 24h NEW	Exposure time 48h OLD
Control	8.5	8.6	8.4	8.4
1:10000	8.6	8.5	8.4	8.4
1:3200	8.7	8.4	8.6	8.6
1:1000	8.7	8.5	8.6	8.6
1:320	8.5	8.6	8.5	8.7
1:100	8.6	8.6	8.4	8.5
1:32	8.6	8.7	8.4	8.5

Temperature (ºC) in the Treatments

Dilution loading rate: 100 mg/L	Exposure time 0h NEW	Exposure time 24h OLD	Exposure time 24h NEW	Exposure time 48h OLD
Control	20	20	20	20
1:10000	20	20	20	20
1:3200	20	20	20	20
1:1000	20	20	20	20
1:320	20	20	20	20
1:100	20	20	20	20
1:32	20	20	20	20

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC50 of test item was calculated to be 9.8 μg/L (0.0098 mg/L) with 95% confidence limit of 6.1 and 16 μg/L (0.0061 and 0.016 mg/L).

Executive summary:

The acute toxicity of the test item N,N-Dimethyl-3-octadccyloxypropylamine to Daphnia magna was determined in a 48-hour semi-static test according to the EU Commission Directive 92/69/EEC, Part C.2, the Commission Regulation (EC) No 440/2008, Part C.2 and the OECD Guideline for Testing of Chemicals,No.202 (2004).

 

Due to the low water solubility of the test item, a dispersion of the test item with the loading rate of 100 mg/L was continuously stirred at room temperature in the dark over 96 hours before each test media preparation. Then, the dispersion was filtered using a two step filtration. The dilutions l:10000, 1:3200, 1:1000, 1:320, 1:100 and l:32 of the supersaturated dispersion were used as test media (after a preceding 3-hour equilibration of all test beakers with the test medium of the highest test concentration (dilution l:32) for correct dosage). A control was tested in parallel.

 

The preparation of the test media was based on the OECD Guidance Document on Aquatic Toxicity Testing of Difficult Substances and Mixture, 2000.

 

At the start of the renewal periods (day 0/day l), the measured concentrations of the test item in the analyzed test media (dilutions l:3200, 1:1000, 1:320, 1:100 and l:32) amounted to 5.0/2.0, 17/7.0 48/22, 156/65 and 633/393 μg/L. At the end of the renewal periods (day 1/day 2), the measured concentrations were l.4/1.5, 4.3/4.5, 22/14, 104/59 and 603/409 μg/L, respectively.

 

The biological results were based on the mean measured concentrations of the test item in the test media calculated as geometric means of the concentrations measured at the start and end of the renewal periods.

 

The 48-hour EC50 of test item was calculated to be 9.8 μg/L (0.0098 mg/L) with 95% confidence limit of 6.1 and 16 μg/L (0.0061 and 0.016 mg/L).