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Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: screening tests
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
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 limited documentation / justification
Justification for type of information:
The supporting QMRF report has been attached
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Principles of method if other than guideline:
The data is predicted using the OECD QSAR toolbox version 3.3 with logKow as the primary descriptor.
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (IUPAC name): 5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride
- Common name: 5-methyl-3-phenylisoxazole-4-carbonyl chloride
- Molecular formula : C11H8ClNO2
- Molecular weight : 221.642 g/mol
- Smiles notation : c1(ccccc1)c1c(C(=O)Cl)c(on1)C
- InChl : 1S/C11H8ClNO2/c1-7-9(11(12)14)10(13-15-7)8-5-3-2-4-6-8/h2-6H,1H3
- Substance type: Organic
- Physical state: Solid
Oxygen conditions:
aerobic
Inoculum or test system:
other: Microorganisms
Duration of test (contact time):
28 d
Based on:
not specified
Parameter followed for biodegradation estimation:
other: BOD
Key result
Parameter:
other: BOD
Value:
0.74
Sampling time:
28 d
Remarks on result:
other: Other details not known
Details on results:
Test substance undergoes 0.74% degradation by BOD in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average value from the 5 nearest neighbours
Domain  logical expression:Result: In Domain

(((((((((("a" or "b" or "c" or "d" )  and "e" )  and "f" )  and "g" )  and ("h" and ( not "i") )  )  and "j" )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and ( not "p") )  )  and ("q" and "r" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Acyl halide OR Allyl OR Aryl OR Ketoxime derivatives OR Oxazole/ Izoxazole by Organic Functional groups ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Acyl halide OR Allyl OR Aryl OR Ketoxime derivatives OR Overlapping groups OR Oxazole/ Izoxazole by Organic Functional groups (nested) ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] OR Aliphatic Carbon [-CH2-] OR Aliphatic Carbon [-CH3] OR Aromatic Carbon [C] OR Aromatic Nitrogen, five-member ring OR Aromatic Oxygen OR Carbonyl, olefinic attach [-C(=O)-] OR Chlorine, olefinic attach [-Cl] OR Miscellaneous sulfide (=S) or oxide (=O) OR Olefinic carbon [=CH- or =C<] OR Oxygen, nitrogen attach [-O-] by Organic functional groups (US EPA) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Aromatic compound OR Carbonic acid derivative OR Halogen derivative by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as days - weeks by Biodeg primary (Biowin 4) ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 5) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Does NOT Biodegrade Fast by Biodeg probability (Biowin 7) ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Non binder, without OH or NH2 group by Estrogen Receptor Binding

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Non binder, impaired OH or NH2 group OR Non binder, non cyclic structure by Estrogen Receptor Binding

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Not calculated by Hydrolysis half-life (pH 6.5-7.4) ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as Halogens AND Non-Metals by Groups of elements

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as Metalloids OR Metals by Groups of elements

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as Group 14 - Carbon C AND Group 15 - Nitrogen N AND Group 16 - Oxygen O AND Group 17 - Halogens Cl AND Group 17 - Halogens F,Cl,Br,I,At by Chemical elements

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Group 15 - Phosphorus P OR Group 16 - Sulfur S by Chemical elements

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as Not categorized by Repeated dose (HESS)

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as 3-Methylcholantrene (Hepatotoxicity) Alert OR Amineptine (Hepatotoxicity) Alert OR Aromatic hydrocarbons (Liver enzyme induction) Rank C OR Chlorphentermine (Hepatotoxicity) Alert OR Nitrosamines (Hepatotoxicity) No rank OR Perhexiline (Hepatotoxicity) Alert OR Tamoxifen (Hepatotoxicity) Alert by Repeated dose (HESS)

Domain logical expression index: "q"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 202 Da

Domain logical expression index: "r"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 246 Da

Validity criteria fulfilled:
not specified
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test chemical 5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride was estimated to be not readily biodegradable in water.

Executive summary:

Biodegradability of 5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride (CAS no. 16883 -16 -2) is predicted using QSAR toolbox version 3.3 with logKow as the primary descriptor. Test substance undergoes 0.74% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 5 -methyl-3 -phenyl-1,2 -oxazole-4 -carbonyl chloride was estimated to be not readily biodegradable in water.

Description of key information

Biodegradability of 5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride (CAS no. 16883 -16 -2) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 0.74% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 5 -methyl-3 -phenyl-1,2 -oxazole-4 -carbonyl chloride was estimated to be not readily biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Various predicted data for the target compound 5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride (CAS No. 16883-16-2) and supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.4 with logKow as the primary descriptor, percentage biodegradability of test chemical 5-methyl-3 -phenyl-1,2 -oxazole-4 -carbonyl chloride(CAS No. 16883-16-2) was estimated.Test substance undergoes 0.74% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride was estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound 5 -methyl-3 -phenyl-1,2 -oxazole-4 -carbonyl chloride(CAS No. 16883-16-2) in the presence of mixed populations of environmental microorganisms was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical 5 -methyl-3 -phenyl-1,2 -oxazole-4 -carbonyl chloride is expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, HSDB, 2017 and EnviChem, 2014) and from secondary source (OECD SIDS, 1998) for the read across chemical 2-Phenylpropene (CAS no. 98-83-9),biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance 2-Phenylpropene. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge (non-adapted) was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance 2-Phenylpropene was determined to 0% by using BOD parameter in 14 days. Thus, based on percentage degradation, 2-Phenylpropene is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 20 days for evaluating the percentage biodegradability of read across substance 1-methyl-2-vinylbenzene (CAS no. 25013-15-4) under aerobic conditions (HSDB, 2017). Domestic sewage (non-adapted) was used as a test inoculums for the study. The percentage degradation of test substance 1-methyl-2-vinylbenzene was determined to 13% in the first 15 days and 32% degradation in between 15-20 days by using Test mat. analysis parameter. Thus, based on percentage degradation, 21-methyl-2-vinylbenzene is considered to be not readily biodegradable in nature.

 

For the read across chemical (1-bromoethenyl)benzene (CAS no. 98-81-7) from authoritative database (J-CHECK, 2017), biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance (1-bromoethenyl)benzene. Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance (1-bromoethenyl)benzene was determined to 0 and 77% degradation by BOD and GC parameter in 28 days. Thus, based on percentage degradation (0% by using BOD parameter), (1-bromoethenyl)benzene is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical5-methyl-3-phenyl-1,2-oxazole-4-carbonyl chloride(from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB & EnviChem and secondary source OECD SIDS), it can be concluded that the test substance 5 -methyl-3 -phenyl-1,2 -oxazole-4 -carbonyl chloridecan be expected to be not readily biodegradable in nature.