bis(hydrogenated tallow C16-18-alkyl)hydroxylamine

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:

1996-02-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

adopted April 4, 1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was hardly soluble in water and the use of Tween-80 as additive did not result in a homogeneous suspension. Thus the test substance was added quantitatively to the test vessels. Ca. 50 mg of the test item was added quantitatively to a test vessel (final volume 500 mL, final concentration ca. 100 mg/L).

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: Activated sludge was collected from a municipal sewage treatment plant ("Waterschap de Maaskant", 's-Hertogenbosch)
- Preparation of inoculum for exposure: The sludge was coarsely sieved and washed with tap-water. A small amount of the sludge was weighed and dried at ca. 105°C. From this result the amount of suspended solids was calculated: the level was 3.9 g/L of sludge. The batch of sludge was used on subsequent days (maximum four days), therefore 50 mL of synthetic sewage feed was added to each litre of activated sludge at the end of each working day. The sludge was kept aerated until use. Before use the pH was checked (measured value: 7.7).

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

30 min

Test temperature:

21.7°C

Nominal and measured concentrations:

Nominal: 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: All glass, 500 ml beakers and 300 ml oxygen bottles
- Aeration: 30 min with clean, oil-free air
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap-water purified by reverse osmosis and subsequently passed over activated carbon and ion-exchange cartridges
- Nutrient solution: in accordance to the guideline

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

30 min

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid: Yes
- Relevant effect levels: EC50(30 min) = 9.15 mg/L

Description of key information

The NOEC value of the test substance on activated sludge was determined to be greater than or equal to 100 mg/L (nominal concentration) in a GLP guideline study according to OECD 209 (NOTOX 166848, 1996).

Additional information

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriate low concentrations.