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

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption, other

Remarks:

adsorption

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Data is from peer-reviewed journal.

Qualifier:

no guideline available

Principles of method if other than guideline:

The adsorption coefficient (Koc) of test substance 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (Phloxine B) (CAS No. 18472-87-2) in sediment was determined.

GLP compliance:

not specified

Type of method:

batch equilibrium method

Remarks:

and HPLC method

Media:

sediment

Specific details on test material used for the study:

- Name of test material (as cited in study report): Phloxine B
- Source of test material: Phloxine B was purchased from ICN Biochemicals (Cleveland, OH).
- Molecular formula: C20H4Br4Cl4O5.2Na
- Molecular weight (if other than submission substance): 829.6388 g/mol
- Smiles notation (if other than submission substance): c1c2c(c(c(c1Br)[O-])Br)Oc3c(cc(c(c3Br)[O-])Br)C24c5c(c(c(c(c5Cl)Cl)Cl)Cl)C(=O)O4.[Na+].[Na+]
- InChl(if other than submission substance): 1S/C20H4Br4Cl4O5.2Na/c21-5-1—3-17(9(23)15(5)29)32-18-4(2-6(22)16(30)10(18)24)20(3)8-7(19(31)33-20)
11(25)13(27)14(28)12(8)26;;/h1-2,29-30H;;/q;2*+1/p-2
- Substance type: Organic
- Physical state: Solid

Radiolabelling:

not specified

Test temperature:

No data

Details on study design: HPLC method:

HPLC analysis was performed with a Hewlett-Packard (HP) HPLC Series 1050 equipped with an autosampler, diode array detector, and HP 3396 Series II integrator.
The HPLC column was Waters Nova Pak C18 (10 cm x 8 mm i.d., 4 μm particle size).
Gradient elution was a mixture of ACN and 50 mM NH4OAc. ACN was increased from 10 to 30% in 5 min (4%/min), to 60% in 10 min
(6%/min), and to 90% in 12 min (12%/min).
After the mobile phase remained at 90% ACN and 10% NH4OAc for 2 min, it was changed to 10% ACN and 90% NH4OAc for 2 min. The detection wavelength was initially set at 493 nm (0-6 min) and changed to 546 nm after 7 min. The flow rate was 2 mL/min. The
injection volume was 50 μL.

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Standard stock solutions were 1 mg/ml of Phloxine B in MeOH. Working standard solutions of Phloxine B were diluted with deionized water.
- Sampling interval: The sediment samples were collected 12, 26, 82, 123, and 284 days after the spill.
- Sample storage before analysis: All standard solutions were covered with aluminum (Al) foil and stored in the dark at 4°C.

Details on matrix:

- Details on collection (e.g. location, depth, contamination history, procedure: Three sediment samples were collected from
the puddle on each sampling date. The sediment samples were taken from the puddle about two inches deep and were approximately one foot apart. The samples were covered with Al foil, frozen within 5 hrs after collection and stored at -20°C.
- Storage conditions: stored at -20°C.
- Textural classification (i.e. %sand/silt/clay): No data available
- pH at time of collection: No data available
- Organic carbon (%): No data available
- Electrical conductivity: No data available
- Redox potential (mv) initial/final: No data available
- Bulk density (g/cm³): No data available
- Biomass (e.g. in mg microbial C/100 mg, CFU or other): No data available
- Preparation and analysis of the sediment samples followed the procedure of Alcantara-Licudine et al. (1997).
The sediment samples were air-dried, sieved through 20 mesh and stored in sealed jars at room temperature. After the moisture
was adjusted to about 10%, Na4EDTA (100 mg) was added and thoroughly mixed. The samples were covered with paraffin film and kept in the dark overnight. Samples were quantitatively transferred to a 2.5-mL extraction vessel. MeOH (1 mL) and n-BA (0.05 mL) were added on top of the soil. The extraction vessel was placed in the extraction chamber for 5 min for temperature equilibration, then statically extracted for 5 min with supercritical CO2 at 60°C/272 atm. Dynamic extraction followed, allowing 50 mL of supercritical CO2 to pass through the sample at 4-8 mL/min. Samples were extracted again with supercritical CO2 at 60°C/476 atm after a second addition of n-BA (0.05 mL) and MeOH (1 mL). The extracts were collected in MeOH (10 mL) in the same vial covered with Al foil. SFE extracts were degassed by sonicating in a lukewarm bath for 0.5 min to remove dissolved CO2, concentrated and filtered through a Gelman 0.45 μm acrodisc for HPLC analysis.

PROPERTIES
- pH: 8.0
- Organic carbon (%): 3.94%
- CEC (meq/100 g): No data
- Other: Fe (%)- 18.7%, Ca- 2398 µg/g, Mg- 109 µg/g

Details on test conditions:

TEST SYSTEM
- Type, size and further details on reaction vessel: Ten milliliters of aqueous solution of Phloxine B was added to 1 gm of air-dried sediment in 40-mL teflon centrifuge tubes. The tubes were capped and shaken vigorously in a Burrell shaker twice a day for 30 min within 72 hr equilibration period in a dark room.
- Water filtered (i.e. yes/no; type of size of filter used, if any): No data
- Amount of soil/sediment/sludge and water per treatment (if simulation test): 1 gm air-dried sediment
- Soil/sediment/sludge-water ratio (if simulation test): No data
- Number of reaction vessels/concentration: No data
- Measuring equipment: No data
- Test performed in closed vessels due to significant volatility of test substance: No data
- Test performed in open system: No data
- Method of preparation of test solution: Standard stock solution was 1 mg/ml of Phloxine B. Working standard solutions of Phloxine B was diluted with deionized water. All standard solutions were covered with aluminum (Al) foil and stored in the dark at 4°C.
- Are the residues from the adsorption phase used for desorption: No data
- Other: Each sediment treatment was replicated at least three times.
Following equilibration, the samples were centrifuged for 10 min at 10,000 rpm in a Sorvall Superspeed RC 2-B rotor. Aliquots of the supernatant solution were diluted for accurate determination of concentrations by capillary zone electrophoresis (CZE). Sediment samples were collected from the spill site and blank samples were analyzed for Phloxine B.

Sample No.:

#1

Duration:

72 h

Initial conc. measured:

10 other: ml/g

Computational methods:

No data available

Type:

Koc

Value:

145.15 dimensionless

pH:

8

% Org. carbon:

3.94

Remarks on result:

other: The Log Koc value was found to be 2.161

Table 1:Properties of sediment samples in Kauai spill site.

 

Sample	pH	Fe (%)	Ca (µg/g)	Mg (µg/g)	Organic carbon (%)	Koc of Phloxine B
Sediment	8.0	18.7	2398	109	3.94	145.15

 

Phloxine B was sorbed by the sediment, and was consistently detected over a 284- day period. Phloxine B concentration was 1420, 1540, 2340, 791, and 485 ppb in the sediment after 12, 16, 82, 123 and 284 days of the spill, respectively.Strong adsorption of phloxine B in sediments was observed.

Validity criteria fulfilled:

not specified

Conclusions:

In conclusion, sediment samples of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) were collected from the spill site for a 284-day period after the accident. However, phloxine B was persistent in the puddle, particularly in the sediment. Distribution coefficients (Koc) of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) was 145.15 (log Koc is 2.161) in sediment. The results indicate that the chemical 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) is likely to show low tendency of sorption to soil and sediment and show moderate migration potential to groundwater.

Executive summary:

This study investigated the dissipation and fate of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) in sediment in the spill site. Distribution coefficients (Koc) of phloxine B was determined.

The sediment samples were collected 12, 26, 82, 123, and 284 days after the spill. Three sediment samples were collected from the puddle on each sampling date. The sediment samples were taken from the puddle about two inches deep and were approximately one foot apart. The samples were covered with Al foil, frozen within 5 hrs after collection and stored at -20°C. The adsorption study was carried out using the batch equilibrium method and by HPLC method. 

Phloxine B was sorbed by the sediment, and was consistently detected over a 284-day period. Phloxine B concentration was 1420, 1540, 2340, 791, and 485 ppb in the sediment after 12, 16, 82, 123 and 284 days of the spill, respectively. The sediment samples were randomly collected about two inches deep from three sites in the puddle. Those all may introduce sample variation and thus the levels of the analytes in the sediment fluctuated.

Adsorption of phloxine B in sediment collected from the spill site was stronger as shown by their Koc values.

Thus, the adsorption coefficient (Koc) of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) in sediment was found to be 145.15

(log Koc is 2.161)along with percentage organic carbon of 3.94%.

The results indicate that the chemical 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) is likely to show low tendency of sorption to soil and sediment and show moderate migration potential to groundwater.

Description of key information

The Adsorption Coefficient of test substance 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 determined as per the HPLC method (OECD Guideline-121). The Log Koc value was found to be 1.549 ± 0.002 at 25°C. The results indicate that the chemical 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid(CAS No. 18472-87-2) is likely to show low tendency of sorption to soil and sediment and show moderate migration potential to groundwater.

Key value for chemical safety assessment

Koc at 20 °C:

35.39

Additional information

Various adsorption studies including experimental data following OECD guideline and from peer-reviewed journals for the substance3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (CAS No. 18472-87-2) were reviewed and are summarized as follows:

 

In the study by UERL (2016), the adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents.A test item solution was prepared by accurately weighing 50mg of test item and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 6.93. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances Benzamide,N-Methylbenzamide,4-Nitrobenzamide,N,N-dimethylbenzamide, 4-methylaniline, 4-chloroaniline, N-methyl aniline, Nitrobenzene, 2 – nitro phenol and Phenanthrene were chosen having K_ocvalue range from 1.239 to 4.09.The Log Koc value of test chemical was determined to be 1.549 ± 0.002 dimensionless at 25°C.This log Koc value indicates that the substance has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

Further, the study by Q. X. Li et al. (Bull. Environ. Contam. Toxicol. (1998) 61:426-432), investigated the dissipation and fate of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) in sediment in the spill site. Distribution coefficients (Koc) of phloxine B was determined. The sediment samples were collected 12, 26, 82, 123, and 284 days after the spill. Three sediment samples were collected from the puddle on each sampling date. The sediment samples were taken from the puddle about two inches deep and were approximately one foot apart. The samples were covered with Al foil, frozen within 5 hrs after collection and stored at -20°C. The adsorption study was carried out using the batch equilibrium method and by HPLC method.  Phloxine B was sorbed by the sediment, and was consistently detected over a 284-day period. Phloxine B concentration was 1420, 1540, 2340, 791, and 485 ppb in the sediment after 12, 16, 82, 123 and 284 days of the spill, respectively. The sediment samples were randomly collected about two inches deep from three sites in the puddle. Those all may introduce sample variation and thus the levels of the analytes in the sediment fluctuated.

Adsorption of phloxine B in sediment collected from the spill site was stronger as shown by their Koc values. Thus, the adsorption coefficient (Koc) of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) in sediment was found to be 145.15 (log Koc is 2.161)along with percentage organic carbon of 3.94%. The results indicate that the chemical 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) is likely to show low tendency of sorption to soil and sediment and show moderate migration potential to groundwater.

 

In a similar study by Q. X. Li et al. (Bull. Environ. Contam. Toxicol. (1998) 61:426-432), investigated the dissipation and fate of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) in soil in the spill site. Distribution coefficients (Koc) of phloxine B was determined. The adsorption study was carried out using the batch equilibrium method and by HPLC method. The distribution of phloxine B in soil systems using a batch equilibrium adsorption procedure was determined as follows. Ten milliliters of aqueous solution of phloxine B or uranine were added to one gram of air-dried soil in 40-mL teflon centrifuge tubes. The tubes were capped and shaken vigorously in a Burrell shaker twice a day for 30 min within 72 hr equilibration period in a dark room. Spike concentrations of phloxine B ranged from 1.25 μg/mL. Each soil treatment was replicated at least three times. Following equilibration, the samples were centrifuged for 10 min at 10,000 rpm in a Sorvall Superspeed RC 2-B rotor. Aliquots of the supernatant solution were diluted for accurate determination of concentrations by capillary zone electrophoresis (CZE). Soil (0-5 cm depth) samples were collected from the spillsite and blank samples were analyzed for phloxine B. Adsorption of phloxine B in Lihue silty clay collected from the spill site was stronger as shown by the Koc value. Strong adsorption of phloxine B on soil particles limits the desorption. Thus, the adsorption coefficient (Koc) of 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) in soil was found to be 188.55(log Koc is 2.275) with percentage organic carbon of 3.10%.The results indicate that the chemical 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid (phloxine B) (CAS No. 18472-87-2) is likely to show moderate tendency of sorption to soil and sediment and show slow migration potential to groundwater.

 

Based on the above studies for target substance 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 adsorption coefficient i.e log Koc value was determined to be in the range of 1.549 ± 0.002 to 2.275. Therefore, it can be concluded that the chemical 3,4,5,6-tetrachloro-2-(1,4,5,8-tetrabromo-6-hydroxy-3-oxoxanthen-9-yl)benzoic acid(CAS No. 18472-87-2) is likely to show low to moderate tendency of sorption to soil and sediment and show moderate to slow migration potential to groundwater.