Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
22 July, 2010
Deviations:
no
Principles of method if other than guideline:
not relevant
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
not specified
Specific details on test material used for the study:
Identity: 4,4’-Oxybis(benzenesulfonyl hydrazide) (OBSH)
CAS No.: 80-51-3
EC No.: 201-286-1
KIT Code No.: K-5450
Lot No.: 201512001
Appearance: White fine powder
Purity: 99.5~100%
Expiry date: December, 2016
Storage conditions: Room temperature / Protect from moisture and light

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
The concentrations at the top, middle and bottom of the stock solution were 45, 45 and 46 mg/L, respectively and CV(%) were 2.2%. This result showed that there was no difference between the point of measurements, and the solution was identified as being very homogeneous
After 30 minutes of aeration, the contents of the first vessel were transferred to a BOD bottle and the respiration rate was measured over a period of up to 10 minutes. Dissolved oxygen readings were recorded every 10 seconds for 10 minutes using a Multi 3430 meter (WTW, Germany).

Test solutions

Vehicle:
yes
Details on test solutions:
to be decided

Test organisms

Test organisms (species):
activated sludge
Details on inoculum:
Activated sludge was collected from the Sewage Treatment Plant, Munsan, Jinju on November 15, 2016. After collection of activated sludge, it was allowed to settle for ca.10 minutes to remove the coarse particles and was sieved using a testing sieve (aperture: 1.00mm). The sludge was centrifuged for 10 minutes at ca.10,000 m/s2 (ca.1,030 g) and the supernatant liquid was discarded. The sludge was re-suspended in deionized water, with shaking, and the wash-water was then removed. The total suspended solids concentration of activated sludge was determined to be 3,150 mg/L by using a moisture analyzer, and the activated sludge was continuously aerated at the test temperature prior to use.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
30 min
Remarks on exposure duration:
If the test substance is rapidly degraded e.g. abiotically via hydrolysis, and the concentration cannot be adequately maintained, a shorter exposure period can be used. Thus the exposure period was reduced to 30 minutes
Post exposure observation period:
no

Test conditions

Hardness:
No data
Test temperature:
20.4 ±0.2 oC
pH:
7.5 -7.6
Dissolved oxygen:
above 60-70%
Salinity:
NA
Conductivity:
NA
Nominal and measured concentrations:
to be decided
Details on test conditions:
Please refer to information stated in the section above
Reference substance (positive control):
yes
Remarks:
3,5-dichlorophenol

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
> 20 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Key result
Duration:
30 min
Dose descriptor:
NOEC
Effect conc.:
5 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Key result
Duration:
30 min
Dose descriptor:
EC10
Effect conc.:
>= 5 - <= 20 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Details on results:
The inhibition of 4,4’-Oxybis(benzenesulfonyl hydrazide) (OBSH) at 1, 5 and 20 mg/L were negative values (percentage). EC50 of 4,4’-Oxybis(benzenesulfonyl hydrazide) (OBSH) is therefore reproted as higher than 20 mg/L.
Results with reference substance (positive control):
The results obtained with the reference item 3,5-dichlorophenol, showed an EC50 of 5.5 mg/L. The EC50was within the 2 to 25 mg/L range, and it was considered acceptable for the test

Any other information on results incl. tables

No data

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
30 min EC50 > 20 mg/L (respiration rate)
30 min NOEC = 5 mg/L (respiration rate)
30 min EC10 =5-20 mg/L (respiration rate)
Executive summary:

The test item was tested according to OECD Guideline no 209: Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation). The study was conducted according to GLP. Resulting NOEC = 5 mg/L EC10 = 5 -20 mg/L and EC50> 20 mg/L based on the endpoint total respiration.