Registration Dossier

Administrative data

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
25 - 26 March 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-Guideline Study, but only draft available. Full test report will be completed .

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
GLP compliance:
yes (incl. certificate)
Remarks:
The Department of Health of the Government of the United Kingdom

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): SH-1, Benzene, 1,1'-(1,2-ethanediyl)bis-, brominated, CAS 1092834-40-6
- Substance type: white powder
- Physical state: solid
- Analytical purity: >99%
- Lot/batch No.: 20090213
- Expiration date of the lot/batch: 12 February 2011
- Storage condition of test material: room temperature

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Results of a preliminary formulation trial showed that the test substance formed a dispersion in RO water (reverse osmosis (RO) water). Therefore, at test initiation appropriate weights were established in one-litre test beakers, RO water (284 mL) was added and the mixtures then treated with ultrasound for ca. 15 minutes in order to form dispersions. The pH of the mixtures was then determined and
no adjustment was necessary.

Test organisms

Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Method of cultivation: A sample of activated sludge was obtained the day before the start of the test from Worlingworth Sewage Treatment Works (Suffolk, UK). In the laboratory, the sample was maintained under aerobic conditions until required. Synthetic sewage (50 mL/L) was added to the stock of activated sludge and this was aerated overnight.

- Preparation of inoculum for exposure:
On the day of the test, the MLSS (mixed liquor suspended solids) content of the sludge was determined (in triplicate) and adjusted to 4 g/L by the addition of tap water. The pH and temperature of the sludge were also measured. Aliquots (200 mL) were then added to each mixture to give a final MLSS concentration of 1.6g/L.

Study design

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

Test conditions

Test temperature:
20 ± 2 ° C
pH:
7.3- 7.7
Nominal and measured concentrations:
nominal concentration: control, 10, 30, 100, 300, 1000 (testet in triplicate) mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: one-litre test beakers
- fill volume: 500 mL
- No. of vessels per concentration (replicates): 1 (3)
- No. of vessels per control (replicates): 1

- Biomass loading rate: Aliquots (200 mL) were then added to each mixture to give a final MLSS
concentration of 1.6g/L.


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Synthetic sewage feed for activated sludge was prepared by dissolving the following in one
litre of RO water:
peptone - 16.0 g
meat extract - 11.0 g
urea - 3.0 g
sodium chloride - 0.7 g
calcium chloride dihydrate - 0.4 g
magnesium sulphate heptahydrate - 0.2 g
di-potassium hydrogen phosphate - 2.8 g


OTHER TEST CONDITIONS
- Adjustment of pH: no


EFFECT PARAMETERS MEASURED: The pH and temperature of the samples were measured
at the start and end of the test.

Reference substance (positive control):
yes
Remarks:
3,5-Dichlorophenol (3,5-DCP), 99%.

Results and discussion

Effect concentrations
Duration:
180 min
Dose descriptor:
EC10
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):
- Results with reference substance valid? yes

Three-hour EC50 for 3,5-DCP = 6.8 mg/L

Any other information on results incl. tables

SH-1 was considered to have had no biologically significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test. The EC20, EC50 and EC80 of the test substance could not be calculated but these must be greater than 1000 mg/L, the highest level tested.

The three-hour EC50 for 3,5-DCP (6.8 mg/L) fulfilled the validity criterion relating to sensitivity to inhibition (acceptable EC50 range 5 to 30 mg/L). The validity criterion relating to the respiration rates in the control (variation not greater than 15%) was also satisfied.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
SH-1 was considered to have had no biologically significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test. The EC20, EC50 and EC80 of the test substance could not be calculated but these must be greater than 1000 mg/L, the highest level tested.