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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
Study period:
June - August 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to a recognised guideline and is GLP compliant.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)
Deviations:
yes
Remarks:
Test extended to 36 days
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Linalyl propionate
EC Number:
205-627-5
EC Name:
Linalyl propionate
Cas Number:
144-39-8
Molecular formula:
C13H22O2
IUPAC Name:
linalyl propionate
impurity 1
Reference substance name:
Unknown impurities
Molecular formula:
not applicable
IUPAC Name:
Unknown impurities
Test material form:
gas under pressure: refrigerated liquefied gas
Details on test material:
Commercial name: Linalyl Propionate
Chemical nature: 3,7-dimethyl-1,6-octadien-3-yl propionate
CAS no: 144-39-8
Lot no: 9000495701
Purity: 97.1%

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Peney-Dessous) was used.
The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.
Duration of test (contact time):
36 d
Initial test substance concentration
Initial conc.:
100 g/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
Test substance samples (25 mg, corresponding to 100 mg/I in a 250-ml flask) were weighed in small aluminium boats and added directly to the test flasks of the SAPROMAT, whereas reference substance samples (sodium benzoate) were added as 1.0 ml of a 25 mg/ml solution in mineral medium.
All flasks are filled with 250 ml of mineral medium. Samples of test or reference substance, or both, are added. Then, a volume of suspended sludge corresponding to 7.5 mg dry weight (as determined from 3.6, generally 1 to 3 ml) is added.
About 2 g of soda lime is placed in an attachment of the stopper, the flasks are closed and placed in the water bath of the SAPROMAT. After temperature and pressure equilibration, the oxygen-meters of the instrument are set to zero (time zero of the experiment).
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Preliminary study:
Not applicable
Test performance:
Oxygen uptakes, as read on the SAPROMAT meters, were corrected to account for the small differences between actual and nominal concentrations of test and reference substances.
Degradation of sodium benzoate exceeded 40 % after 7 days and 65 % after 14 days: the activity of the inoculum is thus verified (validity criterion).
The repeatability validity criterion (not more than 20% difference between replicates) was fulfilled. Therefore, the test is considered valid.
% Degradationopen allclose all
Key result
Parameter:
% degradation (O2 consumption)
Value:
79
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
81
Sampling time:
36 d
Details on results:
Linalyl Propionate underwent 79% biodegradation after 28 days (81 % after 36 days) in the test conditions. Biodegradation started on day 2 and reached 66% at the end of the 10-day window (days 2 to 12).
The curves obtained with the reference substance alone and with Linalyl Propionate + reference substance showed no toxic effect of Linalyl Propionate
to the micro-organisms at the test concentration (100 mg/l).
Thus, Linalyl Propionate should be regarded as readily biodegradable according to this test.

BOD5 / COD results

Results with reference substance:
Degradation of sodium benzoate exceeded 40 % after 7 days and 65 % after 14 days: the activity of the inoculum is thus verified (validity criterion).
The repeatability validity criterion (not more than 20% difference between replicates) was fulfilled. Therefore, the test is considered valid.

Any other information on results incl. tables

Table 1: Measured concentrations and pH values for test and reference substances

Flask no.

Concentration of test substance (mg/L)

Concentration of reference substance (mg/L)

pH Initial

pH Final

1/5

0

0

7.48

7.46

1/6

0

0

7.48

7.42

1/7

0

100.05

7.48

7.91

1/8

0

100.05

7.48

7.73

1/1

103.6

0

7.48

7.46

1/2

105.2

0

7.48

7.39

1/3

107.6

100.05

7.48

7.84

1/4

100.4

100.05

7.48

7.79

Table 2: Results for biological oxygen demand (BOD) and degradation

 

Days:

2

7

12

14

28

36

BOD Sludge

1stflask

6.0

18.0

24.0

24.0

34.0

37.0

2ndflask

8.0

20.0

23.0

23.0

30.0

34.0

Mean

7.0

19.0

23.5

23.5

32.0

35.5

BOD test substance

1stflask

44.6

135.8

192.9

202.6

233.7

239.7

2ndflask

46.0

136.9

204.6

216.0

250.6

261.3

1stfl. corr.

37.6

116.8

169.4

179.1

201.7

204.2

2ndfl. corr.

39.0

117.9

181.1

192.5

218.6

225.8

% degradation

1stflask

14

44

64

67

76

77

2ndflask

15

44

68

72

82

85

mean

14

44

66

70

79

81

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Linalyl Propionate underwent 79% biodegradation after 28 days (81 % after 36 days) in the test conditions. Biodegradation started on day 2 and reached 66% at the end of the 10-day window (days 2 to 12).
Thus, Linalyl Propionate should be regarded as readily biodegradable according to this test.
Executive summary:

The ready biodegradability of Linalyl Propionate was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F.

Linalyl Propionate underwent 79% biodegradation after 28 days (81 % after 36 days) in the test conditions. Biodegradation started on day 2 and reached 66% at the end of the 10-day window (days 2 to 12). The curves obtained with the reference substance alone and with Linalyl Propionate + reference substance show no toxic effect of Linalyl Propionate to the micro-organisms at the test concentration (100 mg/l). Thus, Linalyl Propionate should be regarded as readily biodegradable according to this test.