Sodium 2-hydroxy-3-[(2-hydroxyethyl)[2-[(1-oxo-9-octadecenyl)amino]ethyl]amino]propanesulphonate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992-01-10 to 1992-01-16

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

not applicable

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: Direct dispersion in water
- Controls: Blank control, positive control
- Evidence of undissolved material: Not specified

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Severn Trent PLC Sewage Treatment Plant, Belper, Derbyshire
- Method of cultivation: Sample maintained at 21 °C with continous aeration; used on the day of collection
- Preparation of inoculum for exposure: pH buffered to 6.7 with sodium hydroxide; suspended solids level adjusted to 3.9 g/L

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Post exposure observation period:

Not performed

Hardness:

Not specified

Test temperature:

Not specified

pH:

Not specified

Dissolved oxygen:

Not specified

Salinity:

Not applicable

Conductivity:

Not specified

Nominal and measured concentrations:

Nominal: 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Not specified
- No. of vessels per concentration: 3
- No. of vessels per blank control: 2
- No. of vessels per positive control: 1 per concentration


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
TEST CONCENTRATIONS
- Range finding study : Yes
- Test concentrations: 1.0, 10, 100, 1000
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

No inhibition in blank control observed.

Results with reference substance (positive control):

3-h EC50 = 11.5 mg/L

Table 1: Results for the definitve test

Concentration (mg/L)		O2 consumption rates mg O2/L/min 3 hour contact time	% Inhibition
Control	R1	0.40	-
	R2	0.48	-
Test	1000 R1	0.47	<7>
	1000 R2	0.49	<11>
	1000 R3	0.47	<7>
Reference	3.2	0.39	11
	32	0.08	82

<increase>

r1 - R2: Replicates R1 - R2

Variation between controls: +/- 9%

Table 2: Results for the preliminary range finding test

Concentration (mg/L)		O2 consumption rates mg O2/L/min 3 hour contact time	% Inhibition
Control	R1	0.48	-
	R2	0.46	-
Test	1	0.44	6
	10	0.45	4
	100	0.34	28
	1000	0.27	43
Reference	3.2	0.40	15
	32	0.06	87

Variation between controls: +/- 2%

Validity criteria fulfilled:

not specified

Conclusions:

In an Activated Sludge Respiration Inhibition Test similar to OECD Guideline 209, the 3-h EC50 of the test item was determined to be > 10 mg/L.

Executive summary:

To assess the toxicity of the test item to aquatic microorganisms, a static Activated Sludge Respiration Inhibition Test similar to OECD Guideline 209. A mixed population of activated sludge microorganisms, obtained from the aeration stage of a sewage treatment plant, was exposed to the limit test item concentration of 1000 mg/L (based on the results of a preliminary range finding study). Test solutions were prepared by direct dispersion of the test item in water. In paralellel, a negative control (2 replicates) and a positive control with the reference substance 3,5 -dichlorophenol was performed. The pH was buffered to 6.7 with sodium hydroxide and the suspended solids level was adjusted to 3.9 g/L. In result, no inhibition was observed in the negative control. The 3-h EC50 for the referece substance was determined to be 11.5 mg/L, confirming the suitability of the test item. The 3-h EC50 of the test item was found to be > 10 mg/L.

Description of key information

In an Activated Sludge Respiration Inhibition Test similar to OECD Guideline 209, the 3-h EC50 of the test item was determined to be > 10 mg/L.

Additional information

To assess the toxicity of the test item to aquatic microorganisms, a static Activated Sludge Respiration Inhibition Test similar to OECD Guideline 209. A mixed population of activated sludge microorganisms, obtained from the aeration stage of a sewage treatment plant, was exposed to the limit test item concentration of 1000 mg/L (based on the results of a preliminary range finding study). Test solutions were prepared by direct dispersion of the test item in water. In paralellel, a negative control (2 replicates) and a positive control with the reference substance 3,5 -dichlorophenol was performed. The pH was buffered to 6.7 with sodium hydroxide and the suspended solids level was adjusted to 3.9 g/L. In result, no inhibition was observed in the negative control. The 3-h EC50 for the reference substance was determined to be 11.5 mg/L, confirming the suitability of the test item. The 3-h EC50 of the test item was found to be > 10 mg/L.