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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 (reliable without restriction)

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Version / remarks:
July 1992
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Test material form:
solid: particulate/powder

Study design

Oxygen conditions:
not specified
Inoculum or test system:
activated sludge, domestic, adapted
Details on inoculum:
Activated sludge from the municipal wastewater treatment plant Breisgauer Bucht was used as
inoculum with a concentration corresponding to 30 mg dry solids per litre. The treatment plant
clarifies predominantly domestic wastewater and has a capacity of 600,000 inhabitant
equivalents. Sampling date of activated sludge was 7 August 2018. The dry solids (d.s.) content
of the activated sludge was 3.9 g/L. It was determined by weight measurements after drying at
105°C for 5 hours (mean of triplicate measurements). The activated sludge was washed twice
with tap water by settling the sludge, decanting the supernatant and re-suspending the sludge.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
100 mg/L
Based on:
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
In total three reactors containing the test item, three reactors containing only inoculum (blank)
and three reactors containing the reference compound (reference) were set up.
164 mL of the pre-aerated mineral medium with a pH of 7.6 were filled into the blank flasks. The
test, reference and toxicity control vessels were filled as described in paragraphs 5.4 and 5.5.
After tempering the flasks to the incubation temperature for about one and a half hour, 1.4 mL of
the inoculum were added into each flask, one sodium hydroxide pellet was added to each
rubber quiver inserted in the flasks and the flasks were sealed tightly with the measuring heads
and the test was started. After 28 days the data were read out and the pH in the flasks was
measured on the next day.
Reference substance
Reference substance:
acetic acid, sodium salt

Results and discussion

% Degradation
Key result
Remarks on result:
other: There was no biodegradation of the test item within 28 days, the degradation extent at the end of the test was -1.8%.
Details on results:
There was no biodegradation of the test item within 28 days, the degradation extent at the end of the test was -1.8%

BOD5 / COD results

Results with reference substance:
The reference compound sodium acetate reached the pass level for ready biodegradability
(60% ThOD within a 10-day window) within 8 days.

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
not readily biodegradable
There was no biodegradation of the test item within 28 days, the degradation extent at the end of the test was -1.8%.
Therefore the test item did not reach the pass level for ready biodegradability (60% COD within 28 days and 10 d-window).