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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:
May 2002 - January 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study is GLP compliant and was conducted according to a recognised guideline. All validity criteria were met. Thus, the study is considered to be Klimisch 1.

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)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Linalyl formate
EC Number:
204-120-6
EC Name:
Linalyl formate
Cas Number:
115-99-1
Molecular formula:
C11H18O2
IUPAC Name:
linalyl formate
impurity 1
Chemical structure
Reference substance name:
Linalyl acetate
EC Number:
204-116-4
EC Name:
Linalyl acetate
Cas Number:
115-95-7
Molecular formula:
C12H20O2
IUPAC Name:
1,5-dimethyl-1-vinylhex-4-en-1-yl acetate
impurity 2
Chemical structure
Reference substance name:
Linalool
EC Number:
201-134-4
EC Name:
Linalool
Cas Number:
78-70-6
Molecular formula:
C10H18O
IUPAC Name:
3,7-dimethylocta-1,6-dien-3-ol
Test material form:
liquid
Details on test material:
Commercial name: Linalyl formate
Chemical name: 3,7-dimethyl-1,6-octadien-3-yl formate
Empirical formula: C11H18O2
Molecular weight: 182.2 g/mol
CAS no: 115-99-1

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 was 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):
35 d
Initial test substance concentration
Initial conc.:
100 mg/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. Reference substance samples (sodium benzoate) were added as 1.0 ml of a 25 mg/ml solution in mineral medium.All flasks were filled with 250 ml of mineral medium. Samples of test or reference substance, or both, were added. Then, a volume of suspended sludge corresponding to 7.5 mg dry weight (as determined from 3.6, generally 1 to 3 ml) was added.
About 2 g of soda lime was placed in an attachment of the stopper, the flasks were closed and placed in the water bath of the SAPROMAT. After temperature and pressure equilibration, the oxygen-meters of the instrument were set to zero (time zero of the experiment).
In order to check the toxicity of the test substance to the inoculum a pair of flasks of the volumetric respirometer were filled with mineral medium and the test substance (100 mg/L), plus the reference substance (100 mg/L) and inoculum. Their respiration rate was recorded as for the other flasks.
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 exceeds 40 % after 7 days and 65 % after 14 days: the activity of the inoculum is thus verified.
% Degradationopen allclose all
Key result
Parameter:
% degradation (O2 consumption)
Value:
84
Sampling time:
28 d
Parameter:
% degradation (O2 consumption)
Value:
85
Sampling time:
35 d
Details on results:
Linalyl Formate underwent 84% biodegradation after 28 days (85% after 35 days) in the test conditions. Biodegradation started on day 2 and reached 71 % at the end of the 10-day window (days 2 to 12).
The curves obtained with the reference substance alone and with Linalyl Formate + reference substance show no toxic effect of Linalyl Formate to the microorganisms at the test concentration (100 mg/l).

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

Any other information on results incl. tables

Table 1: Measured concentrations of test substance

Flask no.

Concentration of test substance (mg/L)

Concentration of reference substance (mg/L)

pH initial

pH final

1/1

0

100.1

7.31

7.50

1/2

0

100.1

7.31

7.55

1/3

0

0

7.31

7.29

1/4

0

0

7.31

7.28

2/9

102.2

100.1

7.31

7.56

2/10

106.1

100.1

7.31

7.61

2/11

103.5

0

7.31

7.25

2/12

101.5

0

7.31

7.24

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Conclusions:
Linalyl Formate underwent 84% biodegradation after 28 days (85% after 35 days) in the test conditions. Biodegradation started on day 2 and reached 71 % at the end of the 10-day window (days 2 to 12).
The curves obtained with the reference substance alone and with Linalyl Formate + reference substance show no toxic effect of Linalyl Formate to the microorganisms at the test concentration (100 mg/l).
Thus, Linalyl formate can be regarded as readily biodegradable.
Executive summary:

The ready biodegradability of Linalyl Formate was determined by the manometric respirometry test according to the OECD Guidelines for Testing of Chemicals, Method No. 301 F.

Linalyl Formate underwent 84% biodegradation after 28 days (85% after 35 days) in the test conditions. Biodegradation started on day 2 and reached 71 % at the end of the 10-day window (days 2 to 12). The curves obtained with the reference substance alone and with Linalyl Formate + reference substance show no toxic effect of Linalyl Formate to the microorganisms at the test concentration (100 mg/l). Thus, Linalyl formate can be regarded as readily biodegradable.