Butane-1,3-diol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 September to 12 November 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

also fulfilled: new validity criteria from updated guideline, 2011

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Control (0 mg/L) and 1000 mg/L after 0 h and 72 h
- Sampling method:
a) 0 h: 4 samples (20 mL) from additional flasks containing freshly-prepared control (0 mg/L) and test medium (1000 mg/L)
b) 72 h: contents of replicate flasks (n = 6) were pooled and further samples taken; additional samples were taken from uninoculated flasks with 1000 mg/L
- Sample storage conditions before analysis: two samples were analysed immediately without storage; the other samples were stored in a refrigerator in case further analysis was required

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
A concentrated, aqueous stock was prepared at a nominal concentration of 10 g/L by adding the test substance (1 g) to a volumetric flask (100 ml) and making up to volume with sterile culture medium. An aliquot (10 ml) of this stock was added to each vessel containing inoculated culture medium (90 ml).

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain: CCAP 278/4
- Source (laboratory, culture collection): Culture collection of Algae and Protozoa, Institute of Freshwater Ecology, Cumbria, UK
- Age of inoculum (at test initiation): two days
- Method of cultivation: sterile algal nutrient medium was incoulated with cells aseptically removed from agarslope cultures which had been stored in an illuminated refrigerator; incubation was performed on an orbital incuabtor with continuous illumination at 21-25 °C; after two days appropriate volumes of these primary cultures were transferred to fresh sterile algal nutrient medium; these secondary cultures were incubated as stated before to provide an inoculum in the log phase of growth (normally three days; here: two days)


ACCLIMATION
- Acclimation period: orbital incuabtor with continuous illumination at 21-25 °C
- Culturing media and conditions (same as test or not): same
- Any deformed or abnormal cells observed: none reported

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

0 h: 21.4 °C (control) / 21.5 °C (1000 mg/L)
72 h: 22.8-23.1 °C (control / 1000 mg/L)

pH:

0 h: 7.0 (control) / 7.1 (1000 mg/L)
72 h: 7.5-7.9 (control) / 8.3-8.7 (1000 mg/L)

Nominal and measured concentrations:

a) nominal: 0 mg/L / measured: none detected (< 0.243 mg/L)
b) nominal: 1000 mg/L / mean measured: 1070 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 250 ml conical flasks, fill volume 100 mL
- Aeration: orbital shaker, 150 cycles/min
- Initial cells density: 1.0E04 cells/mL
- Control end cells density: 3.26E06 cells/mL
- No. of vessels per concentration (replicates): 6 + 1 for water quality measurements
- No. of vessels per control (replicates): 6 + 1 for water quality measurements


GROWTH MEDIUM
- Standard medium used: yes


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: filtered, dechlorinated tap water, softened and treated by reverse osmosis, microfiltration and purification (resistivity of 18 Megohm/cm)
- Culture medium different from test medium: no, OECD algal nutrient medium
- Intervals of water quality measurement: no data


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: contnuous illumination
- Light intensity and quality: ca. 9140 lux, "cool white" fluorescent tubes


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Improved Neubauer haemacytometer [counting chamber]


TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable
- Justification for using less concentrations than requested by guideline: limit test
- Range finding study
- Test concentrations: 1000 mg/L
- Results used to determine the conditions for the definitive study: no data

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 1 070 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 1 070 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1 070 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1 070 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

biomass

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none reported
- Any stimulation of growth found in any treatment: yes, at 1000 mg/L (no info whether stimulation is significant)

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EbC50: 0.70 mg/L
- Other: result within the typical range

Reported statistics and error estimates:

Calculations (for the 1000 mg/L concentration):
- average specific growth rate and percentage inhibition
- area under the growth curve and percentage inhibition
- NOEC was determined using Dunnett's test to compare the percentage inhibition in the test concentration with that of the control cultures

Table 1: Results of analytical verification

Nominal concentration (mg/L)		Measured concentration (mg/L)
		0 h	72 h
0 (control)	A	n.d.	n.d.
	B
	Mean
1000	A	1050	1090
	B	1070	1070
	Mean	1060	1080
	Overall mean	1070
	No algae		1060

n.d. = none detected ( 0.243 mg/L)

Table 2: Results of the biological parameters

Mean measured concentration (mg/L)	Mean cell density (72 h)		Mean growth rate (0-72 h)		Mean biomass (72 h)
	(x 10^4cells/mL)	% inhibition	(x 10^-2)	% inhibition	area und. gr. curve (x 10^4)	% inhibition
0 (control)	326	-	8.024	-	6141	-
1070	361	0	8.170	0	6837	0

Table 3: Cell densities - control and test cultures

Measured 1,3- Butylene glycol conc. (g/I)	Replicate	Cell densities (x 10^4cells/mL)
		hours
		24	48	72
nd	R1	10.8	86.9	245
	R2	14.6	75	339
	R3	13.9	86.6	351
	R,	11.1	78.8	393
	R5	10.5	84.3	323
	R6	14	85.3	306
	Mean	12.5	82.8	326
1.07	R1	12.1	86.5	312
	R2	11.6	99.1	408
	R3	12.1	95.5	416
	R4	10.4	104	344
	R5	10.5	87	340
	R6	12.5	101	344
	Mean	11.5	95.5	361

nd : none detected (< 0.243 mg/L).

Validity criteria fulfilled:

yes

Remarks:

including the validity criteria from updated guideline, 2011

Conclusions:

Based on mean measured concentrations, the 72-h ErC50 is > 1070 mg/L and the 72-h NOErC is >= 1070 mg/L.

Executive summary:

The algae growth inhibitory effects of 1,3 -butanediol were studied on Desmodesmus subspicatus following OECD TG 201. A 72 -h limit test with a control (0 mg/L) and the nominal test concentration of 1000 mg/L was set up. Analytical verification of the test concentrations by GLC-FID demonstrated good recovery and revealed a mean measured concentration of 1070 mg/L. The physical-chemical parameters were within acceptable limits. Based on mean measured concentrations, the 72-h ErC50 is > 1070 mg/L and the 72-h NOErC is >= 1070 mg/L.

Description of key information

72 -h ErC50 (Desmodesmus subspicatus, growth rate) > 1070 mg/L, 72-h NOErC (Desmodesmus subspicatus, growth rate) > 1070 mg/L (OECD TG 201, Daly, 2000)

Additional information

In the available key study, algae growth inhibitory effects of 1,3 -butanediol were studied on Desmodesmus subspicatus following OECD 201 (adopted 1984, RL1). A 72 -h limit test with a control (0 mg/L) and the nominal test concentration of 1000 mg/L was set up. Analytical verification of the test concentrations by GLC-FID demonstrated good recovery and revealed a mean measured concentration of 1070 mg/L. The physical-chemical parameters were within acceptable limits. Based on mean measured concentrations, the 72-h ErC50 is > 1070 mg/L and the 72-h NOErC is > 1070 mg/L.