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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:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Principles of method if other than guideline:
The prediction was done by using OECD QSAR tool box v3.3
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (IUPAC name): aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)- Common name: FD&C Yellow No. 5 Aluminum Lake- Molecular formula: C48H33AlN12O27S6- Molecular weight: 495.4038 g/mol-InChl:1S/C16H12N4O9S2.Al/c21-15-13(18-17-9-1-5-11(6-2-9)30(24,25)26)14(16(22)23)19-20(15)10-3-7-12(8-4-10)31(27,28)29;/h1-8,13H,(H,22,23)(H,24,25,26)(H,27,28,29);/b18-17+;- Substance type: Organic- Physical state: solid
Oxygen conditions:
aerobic
Inoculum or test system:
other: Microorganisms
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation:
other: BOD
Key result
Parameter:
other: % biodegradability (BOD)
Value:
0.5
Sampling time:
28 d
Remarks on result:
other: other details not available
Details on results:
The percent biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)was estimated to be 0.5 % by considering BOD as parameter in 28 days.

The prediction was based on dataset comprised from the following descriptors: BOD
Estimation method: Takes average value from the 6 nearest neighbours
Domain  logical expression:Result: In Domain

((((("a" or "b" or "c" )  and "d" )  and "e" )  and "f" )  and ("g" and "h" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as SN1 OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Aromatic azo OR SN1 >> Nitrenium Ion formation >> Unsaturated heterocyclic azo by DNA binding by OECD ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Schiff base formation OR Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives OR Schiff base formation >> Pyrazolones and Pyrazolidinones derivatives >> Pyrazolones and Pyrazolidinones  by Protein binding by OASIS v1.3 ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct Acylation Involving a Leaving group OR Acylation >> Direct Acylation Involving a Leaving group >> Acetates OR SN2 OR SN2 >> SN2 reaction at sp3 carbon atom OR SN2 >> SN2 reaction at sp3 carbon atom >> Alkyl diazo by Protein binding by OECD

Domain logical expression index: "d"

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

Domain logical expression index: "e"

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

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "g"

Parametric boundary:The target chemical should have a value of log BCF max which is >= 1.05 log(L/kg wet)

Domain logical expression index: "h"

Parametric boundary:The target chemical should have a value of log BCF max which is <= 3.91 log(L/kg wet)

Validity criteria fulfilled:
not specified
Interpretation of results:
not readily biodegradable
Conclusions:
The percent biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)was estimated to be 0.5 % by considering BOD as parameter and microrganisms as inoculum in 28 days.
Executive summary:

The biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) (CAS no. 12225 -21 -7) was estimated by using OECD QSAR tool box v3.3 and using six closest read across chemical with log kow as primary descriptor. The percent biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)was estimated to be 0.5 % by considering BOD as parameter  and microrganisms as inoculum in 28 days. On the basis of perent biodegradability it is concluded that this test chemical is not readily biodegradable.

Description of key information

The biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) (CAS no. 12225 -21 -7) was estimated by using OECD QSAR tool box v3.3 and using six closest read across chemical with log kow as primary descriptor. The percent biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)was estimated to be 0.5 % by considering BOD as parameter  and microrganisms as inoculum in 28 days. On the basis of perent biodegradability it is concluded that this test chemical is not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Results of predicted data studies for target chemical aluminum tris (4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) (CAS no. 12225-21-7) and experimental studies for its parent compound as read across chemical are summarized below for biodegradation in water endpoint.

 

In first weight of evidence study the biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) (CAS no. 12225 -21 -7) was estimated by using OECD QSAR tool box v3.3 and using six closest read across chemical with log kow as primary descriptor. The percent biodegradability of test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)was estimated to be 0.5 % by considering BOD as parameter  and microrganisms as inoculum in 28 days. On the basis of percent biodegradability it is concluded that this test chemical is not readily biodegradable.

 

Next study was predicted data study as another weight of evidence in this study Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate)(CAS No: 12225 -21 -7) in the presence of mixed populations of environmental microorganisms. 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  aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) is not readily biodegradable.

 

Next study was experimental study of parent compound of target chemical as read across chemical in this study the aim was to determine the microbial decomposition of Food yellow 4 dye(tartrazine). The biodegradation of read across chemical was determined by three methods under aerobic conditions: Aerobic decomposition of dyes with sludge, Oxygen uptake and BOD determination.

During 10 days of the aerobic experiment, the absorbance of dye solution was measured once in a day for 10 days. 20% decomposition of read across chemical was obtained in 10 days. 3.82 O2 mg/hg – sludge oxygen uptake was obtained in 5 hrs test and the dissolved oxygen contents on the 5th day were essentially the same to initial ones. The low reactivity of aerobic sludge towards dyes was confirmed.

Based on the results obtained from the aerobic degradation assay, Warburg method and BOD determination it can be concluded that tartrazine is not readily biodegradable under aerobic conditions.

 

Another study was also experimental study for parent compound of target chemical as read across chemical in this study the Biodegradability of read across chemical trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4-sulphophenylazo)pyrazole-3-carboxylate (Acid yellow 23) was determined by anlysing percent recovery of read across material. This read across material is dye and inoculums used for biodegradation was obtained from Screened raw waste water from greater Cincinnati Mill Creek sewage treatment plant was used as influent (INF) to three pilot scale activated sludge biological treatment systems (Two experimental and one control). Each system consists of primary clarifier, complete mix aeration basin and secondary clarifier. Influent was spiked with test material at concentration of1 mg/L and 5 mg/L. Then Dye analytical studies were conducted by purified dye compound in organic free influent waste water and mixed liquor. Then influent, primary influent filtrate was passed through column packed with resin. The filter paper and resin were soaked in an ammonia – acetonitrile solution and then soxhlet extracted with ammonia – acetonitrile. The extract was concentrated and brought upto 50 ml volumn with methanol/dimethyl formamaide solution. All extracted samples were analyzed by HPLC with ultraviolet detector.

 Percent recovery determined was 107 % in low spiked and 103 % in high spiked. On the basis of percent recovery value biodegradation of dye was negligible i.e., 0%. Percent biodegradation of read across chemical trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4-sulphophenylazo)pyrazole-3-carboxylatewas observed to be 0.0 % by test material analysis by HPLC parameter. On the basis of percent degradation it is concluded that this read across material is not readily biodegradable.

 

 Last study was also experimental study done for structurally similar read across chemical in this study Biodegradation experiment of read across substance4-Amino-1,1’-azobenzene-3,4'-disulfonic acid (acid yellow 9) was performed using 15 differentStreptomyces spp. for 14 days.The test was performed using 15 different Streptomyces spp as an inoculum. The test substance conc. Used was 50 mg/l.

 Each Streptomyces spp. was grown in a cotton-plugged 250 ml flask containing 25 ml of the following medium: 0.2 M Tris buffer (pH 7.6) 100 ml, 1.0g vitamin-free Casamino acids, 100 µg thiamine, 100 µg biotin, 2 g D-glucose, 900 ml deionized wate. Thiamine, biotin, and D-glucose were filter sterilized and added to the autoclaved medium. The dye was filter sterilized and added at 0.005% (w/v) to the autoclaved basal medium. Cultures were incubated at 37ᵒC for 14 days with shaking (200 rev min1). Three replicates for each strain grown in only the basal medium were incubated as well.

 Degradation of read acros substance was determined by spectrophotometrically and by using HPLC.

 Degradation of the read across substance was confirmed by HPLC. A Hewlett-Packard HP 1090 Liquid Chromatograph equipped with a HP 40 diode array UV-VIS detector and automatic injector was used. The chromatograph was controlled by an HP 9000 series 300 computer which used HP 7995 A ChemStation software. A reverse phase column from Phenomenex (Rancho Palos Verdes, CA, type Spherex 5C 18 size 250 × 2.0 mm, s/no PP/6474A) was used. Each 15-min analysis used a solvent gradient of acetonitrile (solvent A) and 10mM DMS buffer pH 4.5 (solvent B), with the following conditions: 0-5 min, 100% A; 5-12 min, 25% A, 75% B; 12-15 min, 100% B; post time 2 min, injection volume 10µl. Absorption was measured at 250, 325, 350, 400 and 450 nm, and spectra were collected automatically by the peak controller.

 

Spectrophotometric assay was also carried out. A 1 ml sample of actinomycete culture medium was centrifuged and then diluted 2.5 fold with water. Azo dye substrate present was then measured spectrophotometrically (Hewlett-Packard 8452 diode array spectrophotometer operated by PC Vectra computer with HP’s MSTM-DOS/UV-VIS software).The percentage biodegradation of read across substance was determined to be 0% i.e; no degradation of test substance was observed by the 15 different Streptomyces spp. Thus, read across substance was considered to be non-biodegradable.

 

All the studies mentioned above shows that the target chemical, its parent compound and its structurally similar read across chemical is not degradable in water. Therefore it is can be concluded target chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) (CAS no. 12225 -21 -7) is not readily biodegradable.