Bis(2-butoxyethyl) ether

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:

2012-05-02 to 2012-05-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP and no defiencies

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Bis(2-butoxyethyl) ether

EC Number:

204-001-9

EC Name:

Bis(2-butoxyethyl) ether

Cas Number:

112-73-2

Molecular formula:

C12H26O3

IUPAC Name:

1-[2-(2-butoxyethoxy)ethoxy]butane

Details on test material:

- Name of test material (as cited in study report): Diethyleneglycoldibutylether
- Molecular formula: C12H26O3
- Molecular weight: 218.34 g/mol
- Physical state: Liquid, colourless
- Stability under test conditions: Stable
- Storage condition of test material: Room temperature, protected from light, in original container
- Water solubility: 2.8 g/L (20 °C, DIN 51757)
- Density: 0.883 g/cm3 (1013 hPa)
- Log Pow: 1.92

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 6.25 – 12.5 – 25.0 – 50.0 – 100 mg/L.
- Sampling method: The test item Diethyleneglycoldibutylether was analytically verified by GC-MS in the fresh media (0 h) and old media (48 h) of all concentration levels and the control.
Sampling from the freshly prepared media was carried out immediately after homogenisation. Samples of the old media were taken from the approximate centre of the glass flasks. Recoveries of the test item should be within ± 20% of the nominal concentrations.
- Sample storage conditions before analysis:All original samples were stored at 6 ± 2 °C until sample preparation. Prepared samples were stored at room temperature until analysis.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution of 100 mg/L was freshly prepared with dilution water. Dispersion treatment was agitation.
- Eluate: Dilution water
- Differential loading: 6.25 – 12.5 – 25.0 – 50.0 – 100 mg/L
- Controls: Dilution water without test item under the same conditions as the groups.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (STRAUS)
- Strain: Clone 5
- Source: Institut für Wasser-, Boden- Lufthygiene (WaBoLu), further own breeding
- Age at study initiation (mean and range, SD): 2 to 24 h
- Method of breeding: In 2-3 L glass vessels with appr. 1.8 L culture medium, at 20 +/- 2 °C, in an incubator, 16 h illumination, illumination strength max. 20 µExm-2 x s-1
- Feeding during test: No feeding

ACCLIMATION
- Acclimation period: 2 h
- Acclimation conditions (same as test or not): Same as test
- Type and amount of food: No feeding
- Health during acclimation (any mortality observed): Healthy, no mortality observed

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No

Test conditions

Hardness:

Dilution water at test start: 249 (mg CaCO3/L)

Test temperature:

21.8 °C

pH:

Water Quality Parameters at 0 h (Fresh Media)
(measured in one additional replicate per concentration level and control)
Diethyleneglycoldibutylether
Nominal
Test Item Concentration
[mg/L] pH-Value


100 7.88
50.0 7.87
25.0 7.88
12.5 7.88
6.25 7.88
Control 7.91


Water Quality Parameters after 48 h (Old Media)
(measured in all replicates)
Diethyleneglycoldibutylether
Nominal
Test Item Concentration
[mg/L] pH-Values
Replicates
1 2 3 4
100 7.55 7.59 7.59 7.54
50.0 7.64 7.62 7.62 7.62
25.0 7.69 7.64 7.64 7.66
12.5 7.70 7.69 7.69 7.68
6.25 7.56 7.57 7.71 7.70
Control 7.55 7.55 7.45 7.57

Dissolved oxygen:

Water Quality Parameters at 0 h (Fresh Media)
(measured in one additional replicate per concentration level and control)
Diethyleneglycoldibutylether
Nominal
Test Item Concentration
[mg/L] Dissolved O2-Concentration

[mg/L]
100 9.59
50.0 9.45
25.0 9.57
12.5 9.31
6.25 9.57
Control 8.34

Water Quality Parameters after 48 h (Old Media)
(measured in all replicates)
Diethyleneglycoldibutylether
Nominal
Test Item Concentration
[mg/L] Dissolved O2 -Concentration [mg/L]
Replicates
1 2 3 4
100 8.29 7.98 7.77 7.06
50.0 8.09 7.89 7.56 7.54
25.0 8.14 7.77 7.76 7.63
12.5 8.37 8.16 8.54 8.44
6.25 8.27 8.28 8.40 8.36
Control 7.70 7.78 7.63 6.79

Salinity:

Not measured, freshwater

Nominal and measured concentrations:

Please refer to "Any other information on materials and methods"

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers, 50 mL
- Type (delete if not applicable): closed with parafilm
- Material, size, headspace, fill volume: Glass beakers (4 cm ID x 7 cm H), 50 mL
- Aeration: No
- Renewal rate of test solution (frequency/flow rate): One application at test start, static test
- 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): None


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Acc. to Directive 92/69/EEC Method C.2, Annex 1
- Conductivity: Dilution water at test start: 645 µS/cm
- Culture medium different from test medium: Elendt M4 acc. to ELENDT (1990), modified to a total hardness of 160 to 180 mg CaCO3/L
- Intervals of water quality measurement: At test start and test end


OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16:8 light:dark cycle
- Light intensity: Diffuse light, illumination strength max. 20 µE x m-2 x s-1


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility was determined in all groups after 24 h and 48 h. An animal was considered to be immobile, if it was not able to swim within 15 sec after gentle agitation of the test vessel.

TEST CONCENTRATIONS
- Range finding study:
Immobilization Rates in the non GLP Preliminary Range Finding Test
(n = 20, divided into 2 replicates with 10 daphnids each)
Nominal
Test Item Concentration
[mg/L] IMMOBILIZATION [%]
24 h 48 h
Replicates Replicates
1 2 MV 1 2 MV
100 70 60 65 90 100 95
10 0 0 0 0 0 0
1 0 0 0 0 0 0
Control 0 0 0 0 0 0

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

42.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI 34.5-47.0 mg/L

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

28.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI 22.0-37.9 mg/L

Details on results:

- Mortality of control: 0 %
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50/LC50: 1.76 (CI 1.50 - 2.01) mg/L

Reported statistics and error estimates:

EC100-values after 24 and 48 h, the NOEC and LOEC after 48 h were deduced directly from the observation data, without mathematical calculation.

EC10- and the EC50-values were calculated by sigmoidal dose-response regression. The confidence intervals were calculated from the best-fit values, the standard error and the t-distribution with the software GraphPad Prism5, wherever possible. The concentration effect relationships are shown graphically.

Any other information on results incl. tables

Immobilization Rates in the Definitive Test after 24 and 48 h of Exposure

                 (n = 20, divided into 4 replicates with 5 daphnids each)

Diethyleneglycoldibutylether	IMMOBILIZATION [%]
Nominal Test Item Concentration [mg/L]	24 h					48 h
	Replicates					Replicates
	1.	2.	3.	4.	MV	1.	2.	3.	4.	MV
100	40	80	40	60	55	100	100	100	80	95
50.0	60	40	20	40	40	80	80	80	40	70
25.0	0	0	0	0	0	0	0	0	20	5
12.5	0	0	0	0	0	0	0	0	0	0
6.25	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the nominal concentrations of the test item Diethyleneglycoldibutylether the 48-h EC50 for Daphnia magna was estimated to be 42.5 mg/L (95 % confidence limits: 34.5 – 47.0 mg/L). The NOEC after 48 h was 25.0 mg/L. The LOEC after 48 h was 50.0 mg/L.

Executive summary:

In the acute immobilization test with Daphnia magna (STRAUS), the effects of the test item Diethyleneglycoldibutylether(batch number: DEG4136740) were determined according to OECD 202 (2004) from 2012-05-02 to 2012-05-05, with the definitive exposure phase from 2012-05-02 to 2012-05-04, at Dr.U.Noack-Laboratorien, Käthe-Paulus-Str.1, 31157 Sarstedt, Germany.

The study was conducted in sealed glass flasks under static conditions over a period of 48 h with 5concentration levels of the test item Diethyleneglycoldibutylether in the range of 6.25 to 100 mg/L prepared with dilution water in a geometric series with a dilution factor of 2. Twenty daphnids were exposed to each concentration level and the control.

The concentrations of the test item Diethyleneglycoldibutyletherwere analytically verified by   GC-MS in the fresh media (0 h) and in the old media (48 h) of all concentration levels and the control.

The measured concentrations of the test item Diethyleneglycoldibutyletherin the fresh media (0 h) were in the range of 95 to 111 % of the nominal values. The measured concentrations of the test item in the old media (48 h) were in the range of 93 to 120 % of the nominal values, indicating that the concentrations of the test item Diethyleneglycoldibutylether were successfully maintained for the duration of the test.

The endpoints were assessed based on the nominal concentrations of the test item Diethyleneglycoldibutylether(Table 1).

The water quality parameters (pH-value and dissolved oxygen concentration), measured at 0 and 48 h, were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled.

EC₁₀-, EC₅₀- (with Confidence Interval), EC₁₀₀ - Values, NOEC and LOEC

                   (based on the nominal concentrations of the test item Diethyleneglycoldibutylether)

Endpoints (with 95 % confidence limits)	Test Duration [h]	Diethyleneglycoldibutylether
		Nominal Concentration of the Test Item [mg/L]
EC10	24	33.6 (CI: 28.0 – 41.2)
	48	28.5 (CI: 22.0 – 37.9)
EC50	24	61.9 (CI: 49.0 – > 100)
	48	42.5 (CI: 34.5 – 47.0)
EC100	24	> 100
	48	> 100
NOEC	48	25.0
LOEC	48	50.0