2-(oxolan-2-ylmethoxy)ethanol

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 - 21 Jul 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Version / remarks:

corrected July 28, 2011

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Version / remarks:

2009

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Test material

Test material information

Constituent 1

Reference substance name:

2-[(tetrahydrofurfuryl)oxy]ethanol

EC Number:

227-407-8

EC Name:

2-[(tetrahydrofurfuryl)oxy]ethanol

Cas Number:

5831-59-4

Molecular formula:

C7H14O3

IUPAC Name:

2-(tetrahydrofuran-2-ylmethoxy)ethanol

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all test item concentrations and the control
- Sampling method: Samples were taken at test start and test end, duplicate samples were taken at test start and test end.
- Sample storage conditions before analysis: All samples were stored in a refrigerator (4 ± 4 °C), protected from light until analysis was performed.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution of 100 mg test item/L was prepared by dissolving 100.3 mg test item into 1003 mL test water by intense stirring for 30 min. Adequate volumes of this stock solution were diluted with test water to achieve the required test item concentrations.
- Eluate: no
- Differential loading: no
- Appearance of test solutions: Test solutions were clear after preparation.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: No. 61.81 SAG
- Source (laboratory, culture collection): cultivated in the laboratories of the test facility (originally from Sammlung von Algenkulturen, Universität Göttingen, Göttingen, Germany)
- Age of inoculum (at test initiation): 3 d
- Method of cultivation: Cultivation under standardised conditions according to the test guidelines.

ACCLIMATION
- Acclimation period: 3 d
- Culturing media and conditions: same

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

0.24 mmol/L (= 24 mg/L) as CaCO3

Test temperature:

22.4 - 22.7 °C

pH:

8.0 - 9.9 (Control)
8.0 - 10.0 (Test item concentrations)

Nominal and measured concentrations:

Control, 1, 3.2, 10, 32 and 100 mg test item/L (nominal)

Details on test conditions:

TEST SYSTEM
Test vessel:
- Type: open (covered with glass dishes)
- Material, size, headspace, fill volume: glass, size 50 mL, headspace: 0 mL, fill volume: approx. 50 mL
- Initial cells density: 5000 cells/mL
- Control end cells density: 121.773 x 10E+04 cells/mL (mean of six replicates)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- Other: Constantly shaken

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: OECD Medium according to the OECD guideline 201
- Culture medium different from test medium: no
- Intervals of water quality measurement: at test start and test end
- Adjustment of pH: The pH was adjusted with 2 M NaOH to pH 8.1.

OTHER TEST CONDITIONS
- Photoperiod: Continuous illumination
- Light intensity and quality: 4958 lux (range: 4580 to 5320 lux)

EFFECT PARAMETERS MEASURED:
- Determination of cell concentrations: Cell density on each observation time was determined by spectrophotometric measurement and microscopically observation.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study: non-GLP range-finding test

Reference substance (positive control):

yes

Remarks:

potassium dichromate is tested at least twice a year

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: yield

Details on results:

- Exponential growth in the control (for algal test): Yes
- Unusual cell shape: The shape of the algal cells was not obviously affected up to this test concentration. At the highest test item concentration of 100 mg/L the cells showed deformations compared to the control.

Results with reference substance (positive control):

Results of the most recent test with Pseudokirchneriella subcapitata performed with Potassium Dichromate in November / December 2016: EC50 (growth rate, after 72 h): 1.12 mg/L (nominal) (95% CI: 1.06 - 1.17 mg/L).

Reported statistics and error estimates:

Based on the calculated cell densities, the 72 hours ErC50 and the 72 hours EyC50 could not be calculated with a 3-parametric normal concentration distribution function due to the lack of effects and were therefore determined directly from the raw data. The 72 hours LOEC and the 72 hours NOEC values for yield and growth rate were directly determined from the raw data.

Any other information on results incl. tables

Analytical Results TOC-measurements:

Table 1: Results for the Determination of the Test Item in the Test Samples

Sample Description        [mg test item/L]	age           [d]	Total Carbon found     [mg C/L] 1)	Inorganic Carbon found     [mg C/L] 1)	TOC           [mg C/L]	Total Organic Carbon corrected TOC 2)   [mg C/L]	Nominal 3)           [mg/L]	% of nominal
Control	0	8.699	5.030	3.669	n.a.	0.000	n.a.
Control	0	8.645	5.063	3.582	n.a.	0.000	n.a.
Control	3	6.329	3.937	2.392	n.a.	0.000	n.a.
Control	3	5.644	3.556	2.089	n.a.	0.000	n.a.
1	0	n.d.	n.d.	n.d.	n.a.	0.635	n.a.
1	0	n.d.	n.d.	n.d.	n.a.	0.635	n.a.
1	3	n.d.	n.d.	n.d.	n.a.	0.635	n.a.
1	3	n.d.	n.d.	n.d.	n.a.	0.635	n.a.
						mean value (n=4):	n.a.
						RSD (n=4):	n.a
3.2	0	n.d.	n.d.	n.d.	n.a.	2.032	n.a.
3.2	0	n.d.	n.d.	n.d.	n.a.	2.032	n.a.
3.2	3	n.d.	n.d.	n.d.	n.a.	2.032	n.a.
3.2	3	n.d.	n.d.	n.d.	n.a.	2.032	n.a.
						mean value(n=4):	n.a.
						RSD(n=4):	n.a.
10	0	14.865	5.017	9.847	6.222	6.348	98
10	0	14.660	5.021	9.639	6.013	6.348	95
10	3	12.357	4.063	8.294	6.054	6.348	95
10	3	12.063	4.015	8.048	5.807	6.348	91
						mean value (n=4):	95
						RSD (n=4):	3
32	0	29.372	5.095	24.277	20.651	20.315	102
32	0	28.995	4.998	23.997	20.372	20.315	100
32	3	27.256	3.870	23.386	21.145	20.315	104
32	3	26.372	3.916	22.456	20.215	20.315	100
						mean value (n=4):	101
						RSD (n=4):	2
100	0	72.469	5.025	67.444	63.819	63.485	101
100	0	72.398	5.028	67.370	63.744	63.485	100
100	3	70.691	3.675	67.016	64.775	63.485	102
100	3	70.421	3.901	66.519	64.279	63.485	101
						mean value (n=4):	101
						RSD (n=4):	1
						mean value (n=12):	99
						RSD (n=12):	4

1 The tabulated results represent rounded results calculated on the exact raw data

2 The results were corrected by the mean value of the control (carbon content of test media)

3 Calculated using nominal carbon content of the test item (63.485 mg C/L in 100 mg test item/L determined by measuring TOC in pure water) and weighing factor 

RSD: Relative Standard Deviation; DF: Dilution Factor; n.d.: not determined; n.a.: not applicable ;

Test concentrations of nominal 3.2 and 1 mg test item/L were not determined since these concentrations are clearly below the 72-hours NOEC values

Biological Results:

Table 2: Algal Cell Densities during the Test Period of 72 Hours

Nominal concentration [mg test item/L]	Flask No.	Density of algal cells [10000/mL] after
		24 hours	48 hours	72 hours
Control	1	3.674	25.964	132.881
	2	3.250	23.650	114.830
	3	3.462	28.047	122.467
	4	3.462	22.261	109.276
	5	3.674	24.113	118.070
	6	3.674	22.261	133.112
	m	3.533	24.383	121.773
	s	0.173	2.260	9.701
1	1	3.462	25.039	123.393
	2	3.038	25.270	122.236
	3	2.826	22.956	112.979
	M	3.109	24.421	119.536
	S	0.324	1.275	5.708
3.2	1	3.462	21.104	105.573
	2	3.462	25.039	132.187
	3	3.674	23.650	123.624
	M	3.533	23.264	120.461
	s	0.122	1.995	13.586
10	1	3.674	26.890	127.327
	2	3.462	22.724	112.747
	3	3.887	24.113	116.450
	M	3.6742	4.576	118.841
	S	0.212	2.121	7.578
32	1	3.462	23.419	121.310
	2	3.250	24.113	117.376
	3	3.887	23.881	109.276
	M	3.533	23.804	115.987
	S	0.324	0.354	6.136
100	1	3.887	23.650	120.384
	2	3.462	25.501	130.567
	3	3.462	22.261	113.210
	M	3.604	23.804	121.387
	S	0.245	1.625	8.722

m: mean value; s: standard deviation At test start approx. 5000 algal cells/mL were incubated 

Table 3: Growth Rates μ and Percentage Inhibition of μ during the Test Period

Nominal concentration	Growth rates μ [1/day] and % inhibition of μ
	0 - 24 hours		0 - 48 hours		0 - 72 hours
[mg test item/L]	μ	%	μ	%	μ	%
Control	1.954	-	1.942	-	1.831	-
1	1.824	6.7	1.944	-0.1	1.825	0.3
3.2	1.955	0.0	1.919	1.2	1.827	0.2
10	1.993	-2.0	1.946	-0.2	1.823	0.4
32	1.953	0.1	1.931	0.5	1.815	0.9
100	1.974	-1.0	1.931	0.6	1.830	0.0

 

Table 4: Validity criteria for OECD 201

Criterion from the guideline	Outcome	Validity criterion fulfilled
The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72-hour test period.	243.5	Yes
The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1-2 and 2-3, for 72-hour tests) in the control cultures must not exceed 35%	11.2%	Yes
The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 7% in tests with Pseudokirchneriella subcapitata and Desmodesmus subspicatus. For other less frequently tested species, the value should not exceed 10%.	1.4 %	Yes

Applicant's summary and conclusion

Validity criteria fulfilled:

yes