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

Endpoint summary

Description of key information

Transport and distribution

Adsorption/ desorption

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.

Additional information

Transport and distribution

Adsorption/ desorption

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.