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Biodegradation in water: screening tests

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Endpoint:
biodegradation in water: ready biodegradability
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
1. SOFTWARE
EPI-SUITE EPA (USA)

2. MODEL (incl. version number)
BIOWIN 4.10

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
SMILES : O=C(OCC(CC)C)c(c(O)ccc1)c1

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
The QMRF is available in "Attached justification".

5. APPLICABILITY DOMAIN
The QPRF is available in “Attached justification”.

6. ADEQUACY OF THE RESULT
The QPRF is available in “Attached justification”.
Guideline:
other: REACH Guidance on QSARs R.6
Principles of method if other than guideline:
Howard, P.H., Boethling, R.S., Stiteler, W.M., Meylan, W.M., Hueber, A.E., Beauman, J.A., Larosche, M.E. 1992. Predictive model for aerobic biodegradability developed from a file of evaluated biodegradation data. Environ. Toxicol. Chem. 11:593-603.
GLP compliance:
no
Specific details on test material used for the study:
SMILES: O=C(OCC(CC)C)c(c(O)ccc1)c1
Key result
Parameter:
probability of ready biodegradability (QSAR/QSPR)
Remarks on result:
readily biodegradable based on QSAR/QSPR prediction

Biowin1 (Linear Model) : 0.9384

Biowin2 (Non-Linear Model) : 0.9936

Expert Survey Biodegradation Results:

Biowin3 (Ultimate Survey Model): 2.9355 (weeks)

Biowin4 (Primary Survey Model): 3.8159 (days)

MITI Biodegradation Probability:

Biowin5 (MITI Linear Model) : 0.5824

Biowin6 (MITI Non-Linear Model): 0.6741

Anaerobic Biodegradation Probability:

Biowin7 (Anaerobic Linear Model): 0.4339

Ready Biodegradability Prediction: YES

Validity criteria fulfilled:
not applicable
Interpretation of results:
readily biodegradable
Conclusions:
The substance is predicted to be readily biodegradable (EPISUITE, BIOWIN v4.10).
Executive summary:

The substance is predicted to be readily biodegradable (EPISUITE, BIOWIN v4.10).

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From July 1st, 1978 to August 4th, 1978
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
yes
Remarks:
14 day test
GLP compliance:
not specified
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Concentration of sludge: 30 mg/L
Duration of test (contact time):
2 wk
Initial conc.:
100 mg/L
Based on:
not specified
Parameter followed for biodegradation estimation:
test mat. analysis
Remarks:
(GC, direct analysis)
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
BOD (Indirect analysis)
Details on study design:
TEST CONDITIONS
- Test temperature: 25ºC
- pH: 7.0
- pH adjusted: yes
- Suspended solids concentration: 30 mg/l

TEST SYSTEM
- Number of culture flasks/concentration: 2
- Measuring equipment: respirometer, TOC analtser (Coulometric detections)
- Test performed in closed vessels due to significant volatility of test substance: no

CONTROL AND BLANK SYSTEM
- Inoculum blank: 30 mg/l sludge in medium
- Abiotic sterile control: medium + 100 mg/l
- Toxicity control: no


Reference substance:
aniline
Remarks:
(100 mg/L)
Key result
Parameter:
% degradation (O2 consumption)
Value:
83.4
Sampling time:
2 wk
Remarks on result:
other: (indirect analysis)
Key result
Parameter:
% degradation (test mat. analysis)
Value:
100
Sampling time:
2 wk
Remarks on result:
other: (GC, direct analysis)
Results with reference substance:
Degree of decomposition of aniline (7 days): 72.4%
Validity criteria fulfilled:
yes
Remarks:
The difference between replicates has to be <20%. Aniline degradation has to be >40% after 70 days, if the O2 uptake us <50 mg/L (the test was for 14 d not 28 but O2 consumption was really low (2.3mg/L) compared to 60 mg/l.
Interpretation of results:
readily biodegradable
Conclusions:
The test item was determined to be readily biodegradable (BOD=83.4%, Degradation=100%) under test conditions.
Executive summary:

The ready biodegradability test was performed by MITI according to OECD Guideline 301 C. Activated sludge (30 mg/L) were exposed to test item (100 mg/L) under aerobic conditions for 2 weeks. The biodegradation was analysed by indirect analysis (BOD) and direct analysis (GC). The percentages of degradation were determined to be 83.4% based on oxygen consumption and 100% based on GC. Based on these results, the test substance was determined to be readily biodegradable.

Description of key information

Based on the individual biodegradabilities of the main constituents, the test item is deemed readily biodegradable.

Key study: Isopentyl salicylate. OECD 301C. Activated sludge (30 mg/L) were exposed to test item (100 mg/L) under aerobic conditions for 2 weeks. The biodegradation was analysed by indirect analysis (BOD) and direct analysis GC, obtaining a biodegradation of 83.4 and 100% respectively. Based on these results the substance was determined to be readily biodegradable.

Key study: 2 -methylbutyl salicylate. Estimation by EPISUITE, BIOWIN v4.10. The substance is predicted to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
freshwater

Additional information

Based on the information provided by the individual biodegradabilities of the two components of the test item. The substance reaction mass of isopentyl salicylate and 2 -methylbutyl salicylate is determined to be readilly biodegradable.

The ready biodegradability test of Isopentyl salicylate was performed by MITI according to OECD Guideline 301 C. Activated sludge (30 mg/L) were exposed to test item (100 mg/L) under aerobic conditions for 2 weeks. The biodegradation was analysed by indirect analysis (BOD) and direct analysis (GC), obtaining a biodegradation of 83.4 and 100% respectively. Based on these results, the test substance was determined to be readily biodegradable.

2 -methylbutyl salicylate was also predicted to be readily biodegradable using EPISUITE, BIOWIN v4.10.