Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: study was well performed and documented, according to OECD and GLP guidelines

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Batch/Lotnr: 200911040014
- Production date: 04/11/2009
- Shelf-life: 6 months
- Purity of active: 25.09%
- Details of supplier: Proviron Functional chemicals nv
- Date of receipt: 05/02/2010
- Storage: Ambient room temperature 20 to 30°C

Sampling and analysis

Analytical monitoring:
not specified

Test solutions

Vehicle:
not specified

Test organisms

Test organisms (species):
sewage, industrial
Details on inoculum:
- Source: collected from Sri Venkateswara Sugar Mill, Palayasivaram, Kancheepuram District, Tamil Nadu.
- Dry weight was determined and enriched by adding synthetic waste-water (50 ml per litre of sewage sludge)
- Mixture was aerated overnight at 20 +/- 2°C and used for the study
- Sludge containing 3.9 g/L dry weight solid, filterable components

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h

Test conditions

pH:
7.42-7.82
Nominal and measured concentrations:
2.1; 5.92; 18.56; 60.02; 120.16 g/L + control
Details on test conditions:
SEWAGE FEED
- synthetically prepared by dissolving following ingredient in one liter of water: 16.0 g peptone, 11 g meat extract, 3 g urea
0.7 g sodium chloride, 0.4 g calcium chloride, 0.2 g magnesium sulphate and 2.8 g dipotassium hydrogen phosphate.

TEST PROCEDURE
- Preparation of stock solution
- Aeration
- the following were added into 500 ml flat bottom flask and aerated for 3h: 16 ml synthetic sewage feed; X ml stock solution (5; 10; 20; 10 and 80 ml) of 3,5-dichlorophenol/ x mg of Sodium vinyl sulphonate solution (1.0500; 2.9802; 9.4750; 30.0101; 60.0801g); approximately 300 ml water; 200 ml aerated sewage sludge and made up to 500 ml using water
- After the end of 3h, the aeration was stopped. The decrease in oxygen was determined over a period of 10 minutes by reading off the oxygen concentration at every minute.
- The measurements of the oxygen concentrations were carried out with calibrated dissolved oxygen meter.
Reference substance (positive control):
yes
Remarks:
500 mg of 3,5-dichlorophenol was dissolved in 10 ml of 1N NaOH and diluted to 30 ml with distilled water. Then 8 ml of 1N H2SO4 was added by continuous stirring and finally the volume was made upto 1L with distilled water. The pH stock solution = 7.08

Results and discussion

Effect concentrations
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 120 g/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
3h EC50: 22.49 mg/L (measured) with 3,5-dichlorophenol

Any other information on results incl. tables

the respiration rate was determined from the linear range of the oxygen decrease. From the rates of oxygen decrease, the inhibition of the respiration rate of the sewage sludge was calculated by using the following formula:

%inhibition = 1 - (2Rs/(Rc1 +Rc2)) x 100

where Rs = oxygen consumption rate at tested concentration of test substance

Rc1 = oxygen consumption rate, control 1

Rc2 = oxygen consumption rate, control 2

the decrease in oxygen was determined over a period of 10 minutes by reading off the oxygen concentration at every minute.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
From the results it was observed that the test item is non-inhibitory to the microbial organisms up to 120 g/L. The EC50 for Sodium vinyl sulphonate solution (Provichem 2202) after an exposure time of 3 hours was > 120 g/L.