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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2'-dithiodi(benzoic acid)
EC Number:
204-352-8
EC Name:
2,2'-dithiodi(benzoic acid)
Cas Number:
119-80-2
Molecular formula:
C14H10O4S2
IUPAC Name:
2-[(2-carboxyphenyl)disulfanyl]benzoic acid
Test material form:
other: Solid
Details on test material:
The test material had a purity of 75.7%

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
other: unacclimatised secondary effluent
Details on inoculum:
-Source: An unacclimatised secondary effluent was used as teh inoculum for the test. This had been derived from a laboratory scale rolling tube plant, which simulates a trickling filter sewage treatment system. This unit had been fed on 100% sewage obtained from Buckland Sweage Treatment Works, Newton Abbot, Devon, UK, which treats sewage of primarily domestic origin. The rolling tube uni from which the seed was derived was hels at a temperature of 18-22 degrees C.
-Preparation: On day 0 the secondary effluent was filtered through a Whatman GFC filter paper and sparged with CO2 free air until the dissolved inorganic carbon (DIC) was below 1mg/l. During this time the pH was monitored and maintained at 6.8-7.2 by the addition of 5m HCl or 5m NaOH.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
32 mg/L
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
Septum sealed glass bottles were used as test vessels. 3 test vessels per 5 sampling points, 3 blank vessels and 3 reference substance vessels were prepared. 95ml test medium was dispensed into the test vessel, followed by the appropriate weight of test substance. Deionised water was added to make the total volume in each bottle equalt to 100ml.
Bottles were places on an orbital shaker in an incubator at 19.5-20.5 degrees C and 150 rpm.
Sampling occured on days 3, 7, 14, 21, 28.
Reference substance
Reference substance:
acetic acid, sodium salt

Results and discussion

Test performance:
The sodium acetate reference substance showed biodegradation of greater than 60% within a 10 day window, confirming the validity of the test by demonstration that the inoculum used contained viable organisms.
% Degradationopen allclose all
Parameter:
% degradation (CO2 evolution)
Value:
1.8
Sampling time:
3 d
Parameter:
% degradation (CO2 evolution)
Value:
2.8
Sampling time:
7 d
Parameter:
% degradation (CO2 evolution)
Value:
62
Sampling time:
14 d
Parameter:
% degradation (CO2 evolution)
Value:
66
Sampling time:
21 d
Parameter:
% degradation (CO2 evolution)
Value:
65
Sampling time:
28 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
DBTA was shown to be readily biodegradable.