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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:
April-November 2000
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Study conducted in compliance with agreed protocols, with no deviations from standard test guidelines and no methodological deficiences, which do not affect the quality of teh relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions

Data source

Reference Type:
study report

Materials and methods

Test guidelineopen allclose all
according to
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
according to
EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)
GLP compliance:

Test material

Details on test material:
Lot number: 6502/99
Appearence: clear colorless to slightly yellow liquid
Assay: 98.8%w
Water solubility: 0.196 mg/L

Study design

Oxygen conditions:
Inoculum or test system:
sewage, predominantly domestic (adaptation not specified)
Details on inoculum:
Sample taken from secondary effluent of Versailles sewage plant
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
13.99 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
A measured volume (250 ml) of inoculated mineral medium, containing 13.99 mg/L of 1-bromodecane with a theoritical oxygen demand (ThOD) of 2.1702 mgO2/mg as the sole source of organic carbon, is stirred in a closed flask at a constant temperature of 22.5 ±1°C for up to 28 days.
Reference substance
Reference substance:
benzoic acid, sodium salt
at 100 mg/L

Results and discussion

% Degradation
% degradation (O2 consumption)
Details on results:
On the test conditions, the percentage of biodegradation of 1-bromodecane reached 69% within 20 days (plateau) and 73% at the end of the test (28 days).
The 10-d window ended on day 14.

BOD5 / COD results

1.59 mg O2/g test mat.
Results with reference substance:
The percentage of degradation of the reference item has reached a level of 95 % by 14 days which is above the level of 60 % for ready biodegradability.

Any other information on results incl. tables

The method was applied with respect to its quality criteria:

- the difference of extremes of replicate values of the removal of test chemical at the plateau, at the end of the test, or at the end of the 10-d window, was less than 20% ;

- the percentage of degradation of the reference item has reached a level of 95% by 14 days which is above the level of 60% for ready biodegradability ;

- the oxygen uptake of the inoculum blank was far below the normal ;

- pH value in the test suspension was 7.43 at day 28 which is in the range of 6-8.5 ;

- in the toxicity control flasks, containing both the reference item and 1-bromodecane, the percentage biodegradation reached 56% after 14 days.

Since this value is higher than 25%, the test item is not inhibitory for inoculum.

Applicant's summary and conclusion

Validity criteria fulfilled:
Interpretation of results:
readily biodegradable
According to OECD guideline 301, the test item can be considerd as ready biodegradable.
Executive summary:

The biodegradability study of 1 -bromodecane conducted following Method C4 of Regulation 92/69/CEE gives a maximum biodegradation level of 73 % in 28 days.

After the 10-day window, the percentage of biodegradation is 64 %.

The test item did not inhibit the micro-organisms.
The validity criteria of the method were respected.

According to these criteria the test item can be considerd as ready biodegradable.