Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

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:
Dec 8, 1992 - Dec 9, 1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
yes
Remarks:
(test temperatures ~ 16 C. Dry weight of the mixed liquor suspended solids was 5.1 g/L. BOD water used instead of drinking water)
GLP compliance:
yes
Specific details on test material used for the study:
- Substance type: quaternized ammonium compound
- Storage condition of test material: room temperature in the dark
- Other: Test material was supplied to the laboratory as a 4.74% active aqueous dispersion of E4429.01.
- Physical state: solid (E4429.01)
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Appropriate amounts of the test substance were weighed and added to the exposure beakers (see Test Conditions, below)

Test organisms (species):
activated sludge
Details on inoculum:
- Method of cultivation: activated sludge was collected from the oxidation ditch situated on the premises of TNO Zuidpolder Delft on December 7, 1992.
- Preparation of inoculum for exposure: Activated sludge was washed three times by centrifugation and resuspended in dilution water. The dry weight of the sludge suspension was determined. The suspension was diluted to approximately 4 g/L of mixed liquor suspended solids by addition of dilution water, aerated vigorously, and kept at 20°C in the dark. Fifty mL of synthetic sewage feed per litre of sludge suspension was added daily. The dry weight was checked during incubation and the mixed liquor suspended solids re-adjusted prior to use.
- Initial biomass concentration: 5.1 g/L
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h
Test temperature:
~16°C
Nominal and measured concentrations:
Nominal based on dispersion supplied as test substance: 0, 1000 mg dispersion/L
Nominal based on 4.74% active in dispersion: 0, 47.4 mg active/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open during three hour incubation.
- Material, size, headspace, fill volume: 1L glass beakers, 500 mL test solutions
- Aeration: vigourously, continuous
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The (BOD) dilution water was prepared according to the draft NEN 6634: Water (March, 1989)
- Synthetic sewage feed: prepared according to OECD 209.

MIXTURE PREPARATION
A series of mixtures was made containing 16 mL synthetic sewage feed and 284 mL of dilution water. Appropriate amounts of the test substance were weighed and added to the 300 mL solutions. The test was started by adding 200 mL of sludge suspension. The mixtures were prepared at intervals of 10-15 minutes and the first and last mixtures prepared were controls without test substance

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Determination of oxygen concentrations: After 3 hours of incubation, samples were poured into a BOD bottle and stirred vigorously. Oxygen measurements were recorded every minute during a period of about 10 minutes.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: limit test
- Range finding study
- Test concentrations: 0, 11.4, 106 and 1003 mg dispersion/L or 0, 0.54, 5.02, 47.5 mg active/L
- Results used to determine the conditions for the definitive study: No inhibition at the highest concentration tested.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
> 47.4 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Details on results:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: Exposure concentrations of 5, 12 and 30 mg 3,5-dichlorophenol/L yielded a three hour EC50 of 7.8 mg/L.

In a 3-hour toxicity study, activated sludge fed with synthetic sewage was exposed to MDEA-Esterquat at nominal concentrations of 0 and 47.4 mg a.i./L in accordance with OECD 209 (Activated Sludge Respiration Inhibition). The NOEC based on respiration rate was >47.4 mg a.i./L.

Validity criteria fulfilled:
yes
Remarks:
(control respiration rates were within 15% of each other; the 3 h EC50 of 3,5-dichlorphenol was 7.8 mg/L, within the accepted range of 5 to 30 mg/L)
Conclusions:
The 3-hour toxicity of MDEA-Esterquat C16-18 and C18 unsatd. was investigated in a study conducted according to OECD TG 209. The NOEC based on respiration rate was >47.4 mg a.i./L (nominal).
Executive summary:

In a 3-hour toxicity study, activated sludge fed with synthetic sewage was exposed to MDEA-Esterquat C16-18 and C18 unsatd. at nominal concentrations of 0 and 47.4 mg a.i./L in accordance with OECD 209 (Activated Sludge Respiration Inhibition). The NOEC based on respiration rate was >47.4 mg a.i./L.

This study is classified as reliable with restrictions and satisfies the guideline requirements for a toxicity study with microorganisms.

Description of key information

activated sludge respiration inhibition: 3h NOEC> 47.4 mg a.i./L (nominal)

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
47.4 mg/L

Additional information

In a 3-hour toxicity study, activated sludge fed with synthetic sewage was exposed to MDEA-Esterquat C16-18 and C18 unsatd. at nominal concentrations of 0 and 47.4 mg a.i./L in accordance with OECD 209 (Activated Sludge Respiration Inhibition). The NOEC based on respiration rate was >47.4 mg a.i./L.

Categories Display