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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.
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Principles of method if other than guideline:
Prediction was done using OECD QSAR tool box v.3.3
GLP compliance:
not specified
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material : 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt
- Molecular formula : C20H4Br4Cl4O5.xAl
- Molecular weight : 2387.0295 g/mol
- Smiles notation : c1c2c(c(c(c1Br)O)Br)Oc3c(cc(c(c3Br)O)Br)C2c4c(c(c(c(c4Cl)Cl)Cl)Cl)C(=O)[O-].c1c2c(c(c(c1Br)O)Br)Oc3c(cc(c(c3Br)O)Br)C2c4c(c(c(c(c4Cl)Cl)Cl)Cl)C(=O)[O-].c1c2c(c(c(c1Br)O)Br)Oc3c(cc(c(c3Br)O)Br)C2c4c(c(c(c(c4Cl)Cl)Cl)Cl)C(=O)[O-].[Al+3]
- InChl: 1S/3C20H6Br4Cl4O5.Al/c3*21-5-1-3-7(8-9(20(31)32)13(26)15(28)14(27)12(8)25)4-2-6(22)17(30)11(24)19(4)33-18(3)10(23)16(5)29;/h3*1-2,7,29-30H,(H,31,32);/q;;;+3/p-3
- Substance type:Organic
- Physical state:Solid
Oxygen conditions:
not specified
Inoculum or test system:
other: Microorganisms
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation:
other: BOD
Key result
Parameter:
other: BOD
Value:
0.2
Sampling time:
28 d
Remarks on result:
other: other details not available
Details on results:
The percent biodegradation estimated of test chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt is 0.20% by taking 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 5 nearest neighbours
Domain  logical expression:Result: In Domain

(((((("a" or "b" or "c" or "d" or "e" )  or "f" or "g" )  and ("h" and ( not "i") )  )  and "j" )  and "k" )  and ("l" and "m" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Aluminum Compounds AND Not categorized by US-EPA New Chemical Categories

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Aromatic perhalogencarbons OR Aryl OR Aryl halide OR Carboxylic acid OR Fused carbocyclic aromatic OR Fused saturated heterocycles OR No functional group found OR Phenol OR Xanthene by Organic Functional groups ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Aromatic perhalogencarbons OR Aryl halide OR Carboxylic acid OR No functional group found OR Overlapping groups OR Phenol OR Xanthene by Organic Functional groups (nested) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Acid, aromatic attach [-COOH] OR Alcohol, olefinic attach [-OH] OR Aliphatic Carbon [CH] OR Aliphatic Carbon, two phenyl attach [-C-]  OR Aliphatic Oxygen, two aromatic attach [-O-] OR Aluminium [Al] OR Aromatic Carbon [C] OR Bromine, aromatic attach [-Br] OR Bromine, olefinic attach [-Br] OR Carbonyl, olefinic attach [-C(=O)-] OR Carbonyl, one aromatic attach [-C(=O)-] OR Chlorine, aromatic attach [-Cl] OR Chlorine, olefinic attach [-Cl] OR Hydroxy, aromatic attach [-OH] OR Miscellaneous sulfide (=S) or oxide (=O) OR Olefinic carbon [=CH- or =C<] OR Oxygen, one aromatic attach [-O-] OR Oxygen, two olefinic attach [-O-] OR Tertiary Carbon by Organic functional groups (US EPA) ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as Aromatic compound OR Aryl bromide OR Aryl chloride OR Aryl halide OR Carbonic acid derivative OR Carboxylic acid OR Carboxylic acid derivative OR Diarylether OR Ether OR Halogen derivative OR Heterocyclic compound OR Hydroxy compound OR No functional group found OR Phenol by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as Class 4 (Compounds and groups of compounds acting by a specific mechanism) OR Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as Acid moiety OR Phenols, Poly OR SHOULD NOT BE PROFILED by Aquatic toxicity classification by ECOSAR ONLY

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Aromatic acid   [-C(=O)-OH] AND Aromatic alcohol  [-OH] AND Aromatic bromide   [-Br] AND Aromatic chloride   [-CL] AND Aromatic ether  [-O-aromatic carbon] AND Aromatic-CH AND Aromatic-H AND Not calculated by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as Aldehyde   [-CHO] OR Aliphatic acid   [-C(=O)-OH] OR Aliphatic alcohol  [-OH] OR Aliphatic amine   [-NH2  or  -NH-] OR Aliphatic bromide   [-Br] OR Aliphatic chloride   [-CL] OR Aliphatic ether  [C-O-C] OR Amide   [-C(=O)-N  or -C(=S)-N] OR Aromatic amine   [-NH2  or  -NH-] OR Aromatic-CH2 OR Aromatic-CH3 OR Azo group   [-N=N-] OR -C=CH  [alkenyl hydrogen] OR Carbon with 4 single bonds & no hydrogens OR -CH -  [cyclic] OR -CH-   [linear] OR -CH2-  [cyclic] OR -CH2-  [linear] OR Cyanide / Nitriles   [-C#N] OR Ester   [-C(=O)-O-C] OR Fluorine  [-F] OR Ketone   [-C-C(=O)-C-] OR Methyl  [-CH3] OR Nitroso   [-N-N=O] OR Pyridine ring OR Tin  [Sn] OR Triazine ring (symmetric) by Biodegradation fragments (BioWIN MITI)

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Moderate AND Very fast by Bioaccumulation - metabolism half-lives ONLY

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as High (Class III) by Toxic hazard classification by Cramer (original) ONLY

Domain logical expression index: "l"

Parametric boundary:The target chemical should have a value of Molecular weight which is >= 266 Da

Domain logical expression index: "m"

Parametric boundary:The target chemical should have a value of Molecular weight which is <= 489 Da

Validity criteria fulfilled:
not specified
Interpretation of results:
not readily biodegradable
Conclusions:
The percent biodegradability of test chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt estimated was 0.20 % by taking BOD parameter into consideration and microorganism as a inoculum in 28 days. The percent degradation is very less so it is concluded that this test chemical is not readily biodegradable.
Executive summary:

Biodegradability of test chemical is predicted using OECD QSAR tool box v.3.3 using log kow as a primary descriptor. The percent biodegradability of test chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt ( CAS no. 84473 -86 -9) estimated was 0.20 % by taking BOD parameter into consideration and microorganisms as a inoculum in 28 days. The percent degradation is very less so it is concluded that this test chemical is not readily biodegradable.

Description of key information

Biodegradability of test chemical is predicted using OECD QSAR tool box v.3.3 using log kow as a primary descriptor. The percent biodegradability of test chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt ( CAS no. 84473 -86 -9) estimated was 0.20 % by taking BOD parameter into consideration and microorganism as a inoculum in 28 days. The percent degradation is very less so 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

Predicted data from OECD QSAR tool box.v.3.3 for target chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt ( CAS no. 84473 -86 -9) and supporting weight of evidence studies for target chemical’s closest read across chemicals with log Kow as a primary descriptor and structurally similar read across chemical were summarized as below.

Biodegradability of test chemical was predicted using OECD QSAR tool box v.3.3 using log kow as a primary descriptor. The percent biodegradability of test chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt ( CAS no. 84473 -86 -9) estimated was 0.20 % by taking BOD parameter into consideration and microorganism as a inoculum in 28 days. The percent degradation is very less so it is concluded that this test chemical is not readily biodegradable.

 

The supporting weight of evidence study from authoritative database ( J check, 2017) for read across chemical pentabromophenol ( CAS no. 608-71-9) was carried out to test biodegradation. Biodegradation was analysed by using BOD and HPLC parameter and by taking sludge as inoculums at 30 mg/L concentration. The initial concentration of read across chemical was 100 mg/L and study design is of standard type. After 4 weeks (28 days) read across chemical showed 0% biodegradation by BOD and 1 % by HPLC so it is concluded that read across chemical pentabromophenol is not readily biodegradable

 

Another supporting weight of evidence study from same source as stated above ( J check 2017) was performed for read across chemical 5-chloro-2-(2,4-dichlorophenoxy)phenol (CAS no.3380-34-5) to test biodegradation by taking activated sludge as a inoculums at 30 mg/L concentration . Biodegradation was analyzed by using two parameters BOD and HPLC. The initial concentration of test chemical was 100 mg/L and study design is of standard type. After 4 weeks( 28 days) read across chemical 5-chloro-2-(2,4-dichlorophenoxy)phenol showed 0% and 1% biodegradation by BOD and HPLC parameters respectively. So it is concluded that this read across chemical 5-chloro-2-(2,4-dichlorophenoxy)phenol is not readily biodegradable.

 Last study was done from the Journal of Toxicological Sciences, Vol.3 , 193 -204, 1978 for structurally similar read across chemical phloxine B in this study the biodegradability of phloxine B was studied using methods: Aerobic degradability, Warburg method and BOD measurement. Return activated sludge was obtained from the municipal sewage treatment plant, Nakahama, Osaka. Synthetic sewage preparation: Glucos, peptone and potassium dihydrogen phosphate, 30g each, were dissolved in 1 liter water and the pH was adjusted to pH 7.0 with sodium hydroxide. Seeded Dilution water: To 1 liter, 10 ml of supernatant of sludge was added. Aerobic biodegradation assay: To 750ml of sludge (MLSS ca, 3,000 ppm) 250 ml of O.03 M dye solution was added, and bubbled with air sufficiently at 20°C. 5ml sample was taken out once a day. After sampling 5ml synthetic sewage was added to the mixture. Each sample was filtered through filter paper and diluted twenty times prior to the spectrophotometric measurement at the absorption maximum within the visible range. The decrease of dyes concentration was expressed in terms of percent to the initial absorption. The experiment was carried out for 10 days. Oxygen uptake of sludge [Warburg Method]- 2.0 ml of sludge, 0.2 ml of 1000 ppm dye solution, and 0.2 ml of 20% potassium hydroxide were pipetted into the vessel, the side arm and central well, respectively. The sludge and the dye solution were mixed and the vessel was shaken at 25°C. The oxygen uptake was measured. The oxygen uptake by sludge alone was subtracted from those by dyes addition.

Determination of BOD – Dye solution (10, 20, and 40 ppm) were prepared with the seeded dilution water and kept at 20°C (Japanese Industrial Standards Committee, 1971). The dissolved oxygen contents were measured by a dissolved oxygen meter, because of the coloration of the solutions.

As there is no regulation on the color of the effluent by the Water Pollution Control Law, discharge of coloring materials is regulated by only BOD OR COD. The COD, BOD and absorbance at 245 and 545 nm (representing ultraviolet and the visible absorbance) of Phloxine B was studied. During 10 days of the aerobic experiment, the absorbance of dye solution was measured once day for 10 days. Food Red No. 104 was scarcely decreased. Free acids of Red No.104, was precipitated due to the slight acidity (pH 6-7) of the solution. Based on the results obtained from the studies, it can be concluded that Phloxine B is not readily biodegradable under aerobic conditions. Phloxine B was determined to be non- biodegradable in the anaerobic test also performed.

 

On the basis of above results of target chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt from OECD QSAR tool box v.3.3 and its supporting weight of evidence studies from authoritative database and Journal of Toxicological Sciences it is concluded that this test chemical 3,4,5,6-tetrachloro-2-(2,4,5,7-tetrabromo-3,6-dihydroxyxanthen-9-yl)benzoic acid, aluminium salt is not readily biodegradable.