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:
08 January 2010 - 09 February 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source (i.e. manufacturer or supplier) and lot/batch number of test material: Perstorp Holding AB, batch no. 3977901
- Purity, including information on contaminants, isomers, etc.: N/A

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: ambient, dark
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions (e.g. in the exposure medium) and during storage: N/A
- Stability in the medium, i.e. sensitivity of the test material to hydrolysis and/or photolysis: N/A
- Solubility and stability of the test material in the solvent/vehicle and the exposure medium: N/A
- Reactivity of the test material with the incubation material used (e.g. plastic ware): N/A

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing (e.g. warming, grinding): N/A
- Final concentration of a dissolved solid, stock liquid or gel: N/A
- Final preparation of a solid: the test material was liquid
Analytical monitoring:
no
Details on sampling:
Not applicable
Vehicle:
no
Details on test solutions:
A 5 g Polyol TD/L stock solution was prepared by adding Polyol TD (5.0013 g) to a 1000 mL volumetric flask and bringing to volume with deionised water. The solution was ultrasonicated for ca 5 min to aid dissolution.
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
A sample of activated sewage sludge was obtained from Haddington Municipal Sewage Works (a local sewage processing plant, which handles predominantly domestic sewage) on 08 February 2010. On arrival at the laboratory, the volume of sludge was adjusted to 9 L, fed with synthetic sewage feed at a rate of 50 mL/L sludge and held under constant aeration. The solid content of the sludge was determined by shaking the bottle of sludge by handto homogenise thoroughly. Duplicate sub-samples (5mL) of the homogenised sludge were dried in an oven at approximately 105°C and the suspended solids content determined as 2 g/L. To concentrate the solid sewage flocculent to the required level, the sludge was allowed to settle before 4.95 L of the overlying supernatant was siphoned off. The solid content of the sludge was then re-determined and found to be 4.2 g/L, which was acceptable for use. The pH of the sludge was measured as 7.89 upon receipt.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Post exposure observation period:
Not applicable
Hardness:
Not applicable
Test temperature:
18.9 to 19.5°C
pH:
The pH of the sludge was measured as 7.89 upon receipt.
Dissolved oxygen:
Measured during the study.
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal exposure concentrations were 10, 31.6, 100, 316 and 1000 mg/L.
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol
Key result
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
1 000 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):
The 3 h EC50 for 3,5-DCP to activated sludge was estimated to be 11.80 mg/L with 95 % confidence limits of 10.18 and 13.68 mg/L, under the conditions of this test.
Reported statistics and error estimates:
The respiration rate for each vessel was calculated from the recorded oxygen concentrations and expressed as mg O2/L/h for the period between approximately 6.5 and 2.5 mg O2/L. Where respiration was low the calculation was conducted over the full linear range.

The EC50 and associated 95% confidence interval was estimated using the non-parametric Trimmed Spearman-Karber Method (Hamilton et al, 1977), where appropriate.

Respiration rates and percentage inhibition

Treatment

Nominal concentration (mg/L)

Respiration rate
(mg O2/L/h)

% inhibition

Control 1

0

38.80

-

Control 2

0

42.00

-

Mean of controls

-

40.40

-

% difference in controls

-

8.2

-


3,5,-DCP

5

40.91

0

15

12.95

67.95

30

7.83

80.61



Polyol TD

10

43.80

0

31.6

42.11

0

100

43.32

0

316

46.35

0

1000

46.80

0

 

Validity criteria fulfilled:
yes
Conclusions:
As there was no inhibition of respiration at any Polyol TD concentration, the 3 h EC50 for Polyol TD to activated sludge was estimated as >1000 mg/L, under the conditions of this test.
Executive summary:

The toxicity of Polyol TD to activated sewage sludge was investigated in a respiration inhibition test according to OECD test guideline 209. Following three hours exposure to Polyol TD the EC50 was observed to be > 1000 mg/L (based on nominal exposure concentrations), the corresponding NOEC was observed to be 1000 mg/L.

Description of key information

One study was conducted to the effects of Polyol TD on sewage micro-organisms. The toxicity of Polyol TD to activated sewage sludge was investigated in a respiration inhibition test according to OECD test guideline 209. Following three hours exposure to Polyol TD the EC50 was observed to be > 1000 mg/L (based on nominal exposure concentrations), the corresponding NOEC was observed to be 1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

Categories Display