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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:
04 February - 04 March, 2011
1 (reliable without restriction)

Data source

Reference Type:
study report

Materials and methods

Test guidelineopen allclose all
according to guideline
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
according to guideline
EPA OPPTS 835.3110 (Ready Biodegradability)
according to guideline
EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Details on test material:
Name: 1,2-dichloropropane
Purity: 99.69 % w/w
Description: clear liquid
Storage: room temperature

Study design

Oxygen conditions:
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
The activated sludge used for this study was washed by centrifugation (for 10 min.) and the supernatant liquid phase was decanted. The solid material was re-suspended in isotonic saline solution and again centrifuged (for 10 min.). This procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 4 g dry material per litre were mixed with test water and then aerated until use. Before use the sludge was filtered through cotton wool.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
5.3 mg/L
Based on:
test mat.
Reference substance
Reference substance:
other: Sodium benzoate

Results and discussion

% Degradation
other: ThODNH4
Sampling time:
28 d
Remarks on result:
other: St. dev no data
Details on results:
Treatment Concentration Flask Percent of biodegradation after n days of exposure
[mg/L] No. 7 14 21 28
Test item 1a 2.5 5.8 9.2 11.7
5.3 1b 2.5 2.5 7.5 11.7
mean 2.5 4.2 8.3 11.7
Reference item 2a 79.2 82.5 87.5 90.0
3.6 2b 75.8 84.2 85.8 90.0
mean 77.5 83.3 86.7 90.0
Toxicity control Test item: 5.3
Reference item: 3.6 4a 39.7 40.5 41.3 43.3
4b 38.9 39.7 42.9 44.1
mean 39.3 40.1 42.1 43.7

Any other information on results incl. tables

Under the test conditions the percentage biodegradation of1,2 - Dichloropropanereached a mean of 11.7 % after 28 days based on its ThODNH4.

The test item can therefore be considered to be not ready biodegradable.According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThOD.


The reference item Sodium benzoate was sufficiently degraded to a mean of 83.3 % after 14 days, and to a mean of 90.0 % after 28 days of incubation, based on ThODNH4, thus confirming the suitability of the used activated sludge inoculum.


In the toxicity control containing both, the test item and the reference item Sodium benzoate, a mean of 40.1 % biodegradation was noted within 14 days and 43.7 % biodegradation after 28 days of incubation.

Applicant's summary and conclusion

Interpretation of results:
other: not ready biodegradable
The test item can therefore be considered to be not ready biodegradable. According to the test guidelines the pass level for ready biodegradability is removal of 60 % ThOD.
According to the test guidelines the test item can be assumed to be not inhibitory at the applied concentration level of 5.3 mg/L on the activated sludge microorganisms because degradation was >25 % within 14 days.