(E)-3-methyl-5-cyclopentadecen-1-one

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:

From 1995-04-28 to 1995-06-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Experiment conducted under GLP, following OECD guideline. No deviations were observed. Solvent was used but no effects were observed during this study therefore no potential impact of solvent can occur.

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

Inspected on 31 January 1994. Signed on 16 March 1994

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 30 mg/L
- Sampling method: Following preliminary range-finding studies, algae was exposed to an aqueous dispersion of the test material at a concentration of 30 mg/L (6 replicates flasks) for 72h.
- Sample storage conditions before analysis: no data

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: An amount of test material (3.0 g) was dissolved in auxiliary solvent and the volume adjusted to 10 mL to give a 3.0/10 mL solvent stock solution. An aliquot (100 µL) of this solvent stock solution was dispersed in 1L of algal suspensions to give the required test concentration of 30 mg/L.
- Eluate: water
- Differential loading: no
- Controls: control was maintained under identical conditions but not exposed to the test material.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Tween-80-dimethylformamide
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 100µL/L of solvent
- Evidence of undissolved material (e.g. precipitate, surface film, etc): none

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: green algae
- Strain: CCAP 276/20
- Source (laboratory, culture collection): CCAP (Ambleside, Cumbria)
- Age of inoculum (at test initiation): no data
- Method of cultivation: no data

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Remarks on exposure duration:

none

Post exposure observation period:

no data

Hardness:

no data

Test temperature:

24 +/- 1°C

pH:

8.0-10.2

Dissolved oxygen:

no data

Salinity:

not applicable

Nominal and measured concentrations:

- nominal conc.: 30 mg/L
- measured conc.: 29.7 mg/L. See table 6.1.5/3 in "Any other information on results incl. tables".

Details on test conditions:

TEST SYSTEM
- Test vessel: flask
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 100 mL
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- Initial cells density: 3.08 x10^4 cells/mL
- Control end cells density: 8.89 x 10^5 cells/mL
- No. of organisms per vessel: 3.08 x10^6
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no data
- Photoperiod: continuous
- Light intensity and quality: 7000 lux

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 10 and 30 mg/L
- Results used to determine the conditions for the definitive study: No effect observed at these concentrations.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate and biomass

Remarks on result:

other: >= solubility limit (0.69 mg/L in aquatic medium)

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 30 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: growth rate and biomass

Remarks on result:

other: > solubility limit (0.69 mg/L in aquatic medium)

Details on results:

See tables 6.1.5/1 and 6.1.5/2 in "Any other information on results incl. tables".

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

no data

Table 6.1.5/1: Mean cell densities and pH values in the definitive study.

Nominal concentration (mg/L)		pH	Mean cell densities (cells/mL)				pH
		0h	0h	24h	48h	72h	72h
Control	R1	8.1	3.08 x 10^4	1.08 x 10^5	3.13 x 10^5	8.89 x 10^5	10.1
	R2	8.0					10.2
	R3	8.0					10.2
Solvent control	R1	8.0	3.08 x 10^4	1.20 x 10^5	2.85 x 10^5	8.89 x 10^5	10.0
	R2	8.0					10.1
	R3	8.1					10.1
30	R1	8.0	2.93 x 10^4	1.13 x 10^5	2.99 x 10^5	9.07 x 10^5	10.0
	R2	8.0					10.0
	R3	8.0					10.1
	R4	8.0					10.0
	R5	8.0					10.1
	R6	8.0					10.1

Table 6.1.5/2: Inhibition of growth

Nominal concentration (mg/L)	Area under curve at 72h	% inhibition	Growth rate (0-24h)	% inhibition
Control	1.89x10^7	-	0.052	-
Solvent control	1.85x10^7	-	0.057	-
30	1.90x10^7	[2]	0.056	2

[increase in growth as compared to solvent control]

Table 6.1.5/3: Measured concentrations

Samples	Nominal concentration (mg/L)	Concentration found (mg/L)	Expressed as a % of the nominal concentration
0h	solvent control 30 R1-R3 30 R4-R6	<LOQ 30.6 31.2	- 102 104
72h	solvent control 30 R1-R3 30 R4-R6	<LOQ 33.2 47.0	- 111 160

Validity criteria fulfilled:

yes

Conclusions:

Exposure of algae to the test material gave EC50 values greater than the solubility limit (0.69 mg/L in aquatic medium) and NOEC was greater or equal to this value.

Executive summary:

A study was performed to assess the effect of the test material on the growth of the green alga Scenedesmus subspicatus. The method followed that described in the OECD guidelines 201.

Following preliminary range-finding studies, algae were exposed to an aqueous dispersion of the test material (dissolved in Tween-80-dimethylformamide) at a concentration of 30 mg/L for 72h, under constant illumination and shaking at a temperature of 24°C.

Samples of the algal populations were removed daily and cell concentration values determined for each control ant treatment group.

The test concentration of 30 mg/L was the highest attainable test concentration that could be prepared due to the limited solubility of the test material in water and auxiliary solvent and having due regard to the amount of auxiliary solvent permitted in the test under the OECD guidelines.

Analysis of the test solutions at 0 and 72 h showed the measured test concentrations to be near nominal and so the results are based on nominal test concentrations alone.

Exposure of algae to the test material gave EC50 values greater than the solubility limit (0.69 mg/L in aquatic medium) and NOEC was greater or equal to this value.

Description of key information

OECD Guideline 201, GLP, key study, validity 1:

72h-EC50 (Scenedesmus subspicatus) > solubility limit (0.69 mg/L in aquatic medium);

72h-NOEC (Scenedesmus subspicatus) >= solubility limit (0.69 mg/L in aquatic medium).

Additional information

One key study is available to assess the effect of the test material on the growth of the green alga Scenedesmus subspicatus. The method followed that described in the OECD guidelines 201.

Following preliminary range-finding studies, algae were exposed to an aqueous dispersion of the test material (dissolved in Tween-80-dimethylformamide) at a concentration of 30 mg/L for 72h, under constant illumination and shaking at a temperature of 24°C.

Samples of the algal populations were removed daily and cell concentration values determined for each control ant treatment group.

The test concentration of 30 mg/L was the highest attainable test concentration that could be prepared due to the limited solubility of the test material in water and auxiliary solvent and having due regard to the amount of auxiliary solvent permitted in the test under the OECD guidelines.

Analysis of the test solutions at 0 and 72 h showed the measured test concentrations to be near nominal and so the results are based on nominal test concentrations alone.

Exposure of algae to the test material gave EC50 values greater than the solubility limit (0.69 mg/L in aquatic medium) and NOEC was greater or equal to this value.