3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental result using OECD guidelines.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Principles of method if other than guideline:

Biodegradation study was conducted according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) for evaluating the percentage biodegradability of test substance 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid.

GLP compliance:

no

Specific details on test material used for the study:

CAS NO: 18472-87-2
-Chemical name: 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid
-Nature of chemical: Organic
- Purity: 96.21% (Pure dye content, by spectrophotometer)
-Stability: Stable in recommended storage conditions
-Storage conditions: 1. Ambient Temp (23 to 27 °C). Store in a cool place. Keep containers tightly closed in a dry & well - ventilated place.
2. In Refrigerator (4 °C)
3. In Freezer (-10 To 0 °C)
- Physical appearance: Red colored powder
+ Batch no: FG/15-16/0790

Oxygen conditions:

aerobic

Inoculum or test system:

other: mixture of domestic waste water, surface soil and soil samples

Details on inoculum:

Mixed Inoculum Preparation (In-House): Domestic waste water, surface soil and soil samples from polluted sites receiving predominantly domestic waste was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions. This gave the bacterial count as107to 108CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism.

Duration of test (contact time):

28 d

Initial conc.:

32 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: OECD mineral medium was used for the study
- Test temperature: 20°C
- Continuous darkness: Yes
- Other: The water used in this study is deionized water.

TEST SYSTEM
- Culturing apparatus: The apparatus used in this study is BOD bottles, with glass stoppers (125 ml), BOD incubator & oxygen electrode and meter.

CONTROL AND BLANK SYSTEM
- Inoculum blank: it contains only test inoculum
- Procedure control: contains reference compound and inoculum

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

other: BOD and ThOD

Value:

78.07

Sampling time:

28 d

Remarks on result:

other: Other details not known

Details on results:

The BOD28 value of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No.18472-87-2) was observed to be 0.5 mgO2/mg. ThoD was determined by calculation as 0.675 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was found to be 78.07% by 32mg/l. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 84.04 %. Degradation of Sodium benzoate exceeds 78.07% after 7 days and 81.08% after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid.

Observations and calculations:

Mean dissolved oxygen (oxygen consumed mg O2/l) from were recorded inTable 1from dissolve oxygen meter. The amount of oxygen taken up by the microbial population during biodegradation of the test item was corrected for uptake by the inoculum blank (Control) and BOD was calculated accordingly and represented inTable 2. The percent degradation of 0^th, 7^th, 14^th, 21^stand 28^thwere calculated and represented inTable 3.

 

ThOD, BOD₂₈and % Degradation of both reference and the test item, calculated using the formula given in OECD guideline 301D Closed Bottle Test,are summarized inTable 4. The detailed calculations of the same are given inAnnex 4 and Annex 5.

 

Table 5 depicts pH values of 0^th, 7^th, 14^th, 21^stand 28th day of all test vessels.

TABLE 1

DISSOLVED OXYGEN VALUES(oxygen consumed mg O2/l)

 

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
0^thDay	8.6	8.4	8.5
7^thDay	6.4	6	1.1
14^thDay	6.5	4.7	1
21^stday	6.4	4.4	0.8
28^thDay	6.3	5.1	0.6

 

TABLE 2

BOD values (mgO₂/mg)

No. of Days	Test Suspension	Procedure Control (Reference Item)
0^thDay	0	0
7^thDay	0.05	1.3
14^thDay	0.4	1.35
21^stday	0.45	1.375
28^thDay	0.5	1.4

 

TABLE 3

PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
0^thDay	0	0
7^thDay	7.40%	78.07%
14^thDay	59.25%	81.08%
21^stday	66.66%	82.58%
28^thDay	74.07%	84.04%

                    

Table 4

BOD₂₈, THOD AND % BIODEGRADATION VALUES

Method details	BOD28(mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
Test Item	0.5	0.675	74.07%
Reference Item	1.4	1.665	84.04%

 

  TABLE 5

pH OF CLOSED BOTTLE TEST

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
0^thDay	7.04	7.48	7.21
7^thDay	6.83	6.9	6.57
14^thDay	6.34	5.89	6.66
21^stday	6.73	6.73	6.55
28^thDay	6.6	6.93	6.64

 

 

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No.18472-87-2) undergoes 74.07% biodegradation after 28 days in the test condition. Thus, the test item can be inferred/considered as readily biodegradable.

Executive summary:

28-days Closed Bottle test following the OECD guideline 301D to determine the ready biodegradability of the test item 3,4,5,6 -tetrachloro-2 -(1,4,5,8 -tetrabromo-6 -hydroxy-3 -oxoxanthen-9 -yl)benzoic acid (CAS No.18472 -87 -2). The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for the study was 32mg/l and 32mg/l, while that of inoculum was 32ml/l. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD₂₈value of3,4,5,6 -tetrachloro-2 -(1,4,5,8 -tetrabromo-6 -hydroxy-3 -oxoxanthen-9 -yl)benzoic acid (CAS No.18472 -87 -2) was observed to be 0.5mgO₂/mg. ThOD was calculated as 0.675mgO₂/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was found to be 74.07%. Based on the results, the test item, under the test conditions, was found to be readily biodegradable at 20 ± 1°C over a period of 28 days.

Description of key information

The test item 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No.18472-87-2) undergoes 74.07% biodegradation after 28 days in the test condition. Thus, the test item can be inferred/considered as readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

28-days Closed Bottle test following the OECD guideline 301D to determine the ready biodegradability of the test item 3,4,5,6 -tetrachloro-2 -(1,4,5,8 -tetrabromo-6 -hydroxy-3 -oxoxanthen-9 -yl)benzoic acid (CAS No.18472 -87 -2). The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for the study was 32mg/l and 32mg/l, while that of inoculum was 32ml/l. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD₂₈value of3,4,5,6 -tetrachloro-2 -(1,4,5,8 -tetrabromo-6 -hydroxy-3 -oxoxanthen-9 -yl)benzoic acid (CAS No.18472 -87 -2) was observed to be 0.5mgO₂/mg. ThOD was calculated as 0.675mgO₂/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was found to be 74.07%. Based on the results, the test item, under the test conditions, was found to be readily biodegradable at 20 ± 1°C over a period of 28 days.