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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
01.07.98-08.10.98
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
Solution A: KH2PO4 8.5g K2HPO4 21.75g Na2HPO4.2H2O 33.4g NH4Cl 0.5g
Solution B:CaCl2 27.5g
Dissolved in water and made up to 1 litre
Solution C:MgSO4.7H2O 22.5g
Dissolved in water and made up to 1 litre
FeCl3.6H2O 0.25g HCl Conc. One drop
SolutionD:
Dissolved in water and made up to 1 litre

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
Fresh acticated sludge from a biological waste water treatment plant treating predominantly domestic sewage(City of Geneva,Aire) was used.
Duration of test (contact time):
ca. 28 d
Initial test substance concentration
Initial conc.:
ca. 100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Test condition
-Composition of medium: Made in accordance with OECD 301F guideline
-Solubilising agent: none
-Test temperature: 22±1℃
-PH: 7.4±0.2
-PH adjusted: yes
-Suspended solids concentration: 30 mg/l
Test system
-Culturing apparatus: Flasks of the SAPPOMAT D12, made by J.M. VOITH Gmbh, D-7920 Heidenheim
-Measuring equipment: The respirometer used during this study is a SAPPOMAT D12, made by J.M. VOITH Gmbh, D-7920 Heidenheim
Control and blank system
-Inoculum blank: yes( mineral medium+ inoculum)
-Abiotic sterile control: yes (mineral medium + test chemical (100mg/l)+Reference substance (100mg/l)
-Toxicity control: Yes (mineral medium + test chemical (100mg/l)+Reference substance (100mg/l+ inoculum

A measured volume of inoculated mineral medium, containing a known concentration of test substance (100mg/l) as nominal sole source of organic carbon, is stirred in a closed flask at a constant temperature (±1℃) for up to 28 days. The consumption of oxygen is determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant the gas volume in the respirometer flask. Evolved carbon dioxide is absorbed in soda lime pellets. The test chemical (corrected for uptake by blank inoculums, run in parallel) is expressed as a percentage of ThOD (Theoretical Oxygen Demand, calculated from the elemental composition, assuming that carbon is oxidized to carbon dioxide and hydrogen to water).
Reference substance
Reference substance:
benzoic acid, sodium salt
Remarks:
Purity: min 99.0%

Results and discussion

Preliminary study:
Not performed
Test performance:
No unusual observations affecting results performed
% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Value:
ca. 82
Sampling time:
7 d
Parameter:
% degradation (O2 consumption)
Value:
ca. 85
Sampling time:
12 d
Parameter:
% degradation (O2 consumption)
Value:
ca. 87
Sampling time:
14 d
Parameter:
% degradation (O2 consumption)
Value:
ca. 89
Sampling time:
21 d
Parameter:
% degradation (O2 consumption)
Value:
ca. 90
Sampling time:
28 d
Details on results:
See "Any other information on results incl. tables

BOD5 / COD results

Results with reference substance:
Degradation of sodium benzoate exceeds 40% after 7days and 65% after14days: the activity of the inoculum is thus verified and the test is considered as valid.

Any other information on results incl. tables

Test substance: Coumarin Pure Crystals

B=(B1 +B2)/2; D1=100*(C1 -B)/ThOD*[S]; D2=100*(C2 -B)/ThOD*[S]; D=(D1 +D2)/2. [S]:Initial test substance concentration(mg/L).

 

Days:

2

7

12

14

21

28

BOD

Sludge

1rst flask   B1

2nd flask   B2

mean      B

8.0

10.0

14.0

14.0

16.0

16.0

8.0

14.0

20.0

20.0

22.0

22.0

8.0

12.0

17.0

17.0

19.0

19.0

 

BOD

Test

Subst.

1rst flask   C1

2nd flask   C2

1rst fl.corr  C1-B

2nd fl.corr  C2-B

104.0

186.0

198.6

201.4

206.3

210.1

89.2

179.1

190.7

193.5

200.3

203.1

96.0

174.0

181.6

184.4

197.3

191.1

81.2

167.1

173.7

176.5

181.3

184.1

%

degr

1rst flask   D1

2nd flask   D2

mean      D

46

84

87

89

90

92

39

80

84

85

87

89

43

82

85

87

89

90

Test substance: SODIUM BENZOATE

B=(B1 +B2)/2; D1=100*(C1 -B)/ThOD*[S]; D2=100*(C2 -B)/ThOD*[S]; D=(D1 +D2)/2. [S]:Initial test substance concentration(mg/L).

 

Days:

5

7

10

14

21

28

BOD

Sludge

1rst flask   B1

2nd flask   B2

mean      B

10.0

10.0

14.0

14.0

16.0

16.0

12.0

14.0

18.0

20.0

22.0

22.0

11.0

12.0

16.0

17.0

19.0

19.0

 

BOD

Refer

Subst.

1rst flask   A1

2nd flask   A2

1rst fl.corr  A1-B

2nd fl.corr  A2-B

130.0

142.0

156.0

168.0

176.0

180.0

128.0

140.0

154.0

164.0

170.0

172.0

119.0

130.0

140.0

151.0

157.0

161.0

117.0

128.0

138.0

147.0

151.0

153.0

%

degr

1rst flask   D1

2nd flask   D2

mean      D

71

78

84

91

94

97

70

77

83

88

91

92

71

77

83

89

92

94

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Degradation of sodium benzoate exceeds 40% after 7days and 65% after14days: the activity of the inoculum is thus verified and the test is considered as valid.
Interpretation of results:
readily biodegradable
Conclusions:
Coumarin pure crystal undergoes 90% biodegradation after 28 days in the test conditions. Biodegradation starts on day 2 and reaches 85% at the end of the 10-day window (days 2 to 12).
Thus coumarin pure crystal should be regarded as readily biodegradation according to this test.
The curves obtained with the reference substance alone and with coumarin pure crystals + reference substance show no toxic effect of coumarin pure crystal to the micro-organisms at the test concentration.
Executive summary:

The Read Biodegradability of COUMARIN PURE CRYSTALS was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F.

COUMARIN PURE CRYSTALS undergoes 90% biodegradation after 28days in the test conditions. Biodegradation stars on day 2 and reaches 85 % at the end of the 10-day window(days 2-12).

Thus, COUMARIN PURE CRYSTALS should be regarded as readily biodegradable according to this test.

At the concentration used in the test (100mg/l). COUMARIN PURE CRYSTALS is not inhibitory to the micro-organisms.