Sodium 3-(allyloxy)-2-hydroxypropanesulphonate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: samples taken from all concentrations and control at t=0, t=24 and t=48
- Sampling method: at end of exposure period replicates were pooled before sampling of 3 ml solution
- Sample storage conditions before analysis: in the freezer (stability under conditions was determined in previous project)

Vehicle:

no

Details on test solutions:

Preparation of test solution started with the highest test concentration of nominal 400 mg/L. This concentration corresponded to 100 mg a.i./L. No special treatment other than a short period of magnetic stirring (15 minutes) was applied to ensure complete dissolution in the test medium. The pH of this solution was above 9.2 and as a consequence adjusted to 8.3 using 1M HCl (Merck, Darmstadt, Germany). The lower test concentrations were prepared by subsequent dilutions in test medium. The final test solutions were all clear and colourless.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain: NIFA CHL 1
- Source (laboratory, culture collection): in-house laboratory
- Age of inoculum (at test initiation):
- Method of cultivation:

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): standard medium M1 (according NPR 6505)
- Any deformed or abnormal cells observed:

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Test temperature:

22.4-23.2 °C

pH:

8.0-8.1

Nominal and measured concentrations:

0.1, 1.0, 10 and 100 mg a.i./L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL
- Material, size, headspace, fill volume: all-glass, 50 mL test solution
- Aeration:
- Initial cells density: 10^4 cells/mL
- Control end cells density: 50.9 x 10^4 cells/mL (mean cell density)
- No. of vessels per concentration (replicates): 6 (limit test), 3 (range-finding)
- No. of vessels per control (replicates): 6, 2 (highest concentration without algae), 1 (lower concentration without algae), 1 extra replicate of each test group with algae for sampling purposes


GROWTH MEDIUM
- Standard medium used: yes (standard medium M2 according to OECD 201)


OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: no adjustment during exposure period
- Photoperiod: continuosly
- Light intensity and quality: 84 to 97 µE x m-2 x s-1


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Varian Cary 50 counter
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Results with reference substance (positive control):

- Results with reference substance valid? yes, observations within historical range of laboratory
- ErC50 (72h): 2.1 mg/L (95% c.i.: 1.5-3.0 mg/L)

Number of inoculated cells at t=0: 1 x 10^4cells /mL
Concentration HAPS (mg a.i./L)	Vessel number	Exposure time (hours)
		0	24	48
Control	1	1.00	9.50	55.28
	2	1.00	8.14	48.81
	3	1.00	9.21	48.66
	4	1.00	8.14	52.63
	5	1.00	8.40	49.52
	6	1.00	8.37	50.48
0.1	1	1.00	8.02	51.26
	2	1.00	6.92	46.21
	3	1.00	8.00	53.67
1.0	1	1.00	6.59	48.55
	2	1.00	6.40	49.68
	3	1.00	6.59	47.00
10	1	1.00	7.17	49.65
	2	1.00	9.09	50.94
	3	1.00	8.77	44.69
100	1	1.00	6.73	38.12
	2	1.00	7.27	48.19
	3	1.00	8.06	43.86
	4	1.00	7.04	41.49
	5	1.00	7.27	45.39
	6	1.00	7.17	43.63

Validity criteria fulfilled:

yes

Conclusions:

No adverse effect to the growth rate of Pseudokirchneriella subcapitata in this test up to the highest concentration could be observed.

Executive summary:

The study procedures described in this report were based on the OECD guideline No. 201, 2006. In addition, the procedures were designed to meet the test methods of the EEC Directive 92/69, Part C.3, 1992 and the ISO International Standard 8692, 2004. The batch of HAPS tested was a light yellow liquid consisting of 25.0% HAPS (active ingredient: a.i.), 72.75% water and 2.25% sodium hydroxide. HAPS was completely soluble in test medium at the concentrations tested. All concentrations reported were corrected for the purity of the test substance (25%).

A combined limit/range-finding test was performed. Exponentially growing algal cultures were exposed to a control and a nominal HAPS concentration of 100 mg a.i./L in the limit test. In the combined range-finding test algae were exposed to nominal HAPS concentrations of 0.1, 1.0 and 10 mg a.i./L. The total test period was 48 hours and the initial algal cell density was 10^4 cells/mL. Samples for analytical confirmation of actual exposure concentrations were taken at the start, after 24 and 48 hours of exposure. Analysis of the samples taken during the test showed that the measured concentrations were in agreement with nominal (94 -98%). The study met the acceptability criteria predescribed by the protocol and was considered valid. No significant reduction of growth rate was recorded up to and including a HAPS concentration of 100 mg a.i./L. Both the EC50 for growth rate reduction and the EC50 for yield inhibition exceeded 100 mg a.i./L (corrected for purity and based on analytically confirmed nominal concentrations.)

Description of key information

In absence of visible effects in the study with Pseudokirchneriella subcapitata key value for further assessment is set to 100 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L