Dialuminium tris[2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6-tetrachlorobenzoate]

PBT assessment

PBT assessment: overall result

PBT status:

the substance is not PBT / vPvB

Justification:

Here follows a compiled description of the PBT assessment:

Persistence assessment

The tested substance fulfils the P criterion within Annex XIII based on the assessment that here follows:

 

                     Abiotic degradation

Hydrolysis of Dialuminium tris(2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6-tetrachlorobenzoate) (CAS no. 15876 -58 -1) is predicted using OECD QSAR toolbox version 3.4 (2017) with logKow as the primary descriptor. The estimated half-life of Dialuminium tris(2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6-tetrachlorobenzoate) was estimated to be 146 days, indicating that it is not hydrolysable. If released into the environment there is a risk that this compound and compounds with molecular similarity (such as CAS 15876-58-1) may persist in the environment..

 

                     Biotic degradation in water

The technical dossier of CAS 15876-58-1 contains the following estimation models for biotic degradation:

1)     Biodegradability of Dialuminium tris(2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6-tetrachlorobenzoate) (CAS no. 15876 -58 -1) is predicted using OECD QSAR toolbox version 3.4 with logKow as the primary descriptor. Test substance undergoes 1.82% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical Dialuminium tris(2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6 -tetrachlorobenzoate) was estimated to be not readily biodegradable in water. (QSAR 3.4 prediction, SSS Europe AB, Lund, Sweden, 2017).

2)     The aim of the research evaluation was to study the aerobic biodegradability potential of CAS 17372-87-1 (i.e.Acid Red 87). One used a modified OECD 302B test. The main modification from the OECD method were the extension of the test period from 28 days to 42 days and weekly feeding of the inoculum (i.e.100 mg/L yeast extract). The sources of the activated sludge were communal or industrial treatment plants. The initial concentration of Acid Red 87 was 100 mg/L. The dissolved organic carbon (DOC) was only reduced by 3% after 42 day of incubation with Acid Red 87. The tested compound is considered as readily biodegradable if the test shows 70% DOC removal within 14 days, since this indicates biodegradation. Hence, the chemical is not inherently biodegradable under the tested conditions (Chemosphere, 1986, 15(4):479-491).

3)     The biodegradability of phloxine B was studied using different methods such as aerobic degradability, Warburg method and BOD measurement. Return activated sludge was obtained from the municipal sewage treatment plant, Nakahama, Osaka. Synthetic sewage and Seeded Dilution water were also prepared. 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 of 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. 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.

The percentage degradation of test substance 2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-3',6'-dihydroxy-3H-spiro[2-benzofuran-1,9'-xanthen]-3-one (Phoxine B) was determined to be 0% by using Test mat. analysis and Oxygen uptake in 10 days. Thus, based on percentage degradation test chemical 2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-3',6'-dihydroxy-3H-spiro [2-benzofuran-1,9'-xanthen]-3-one was considered to be not readily biodegradable in nature. (The Journal of Toxicological Sciences, Vol.3 , 193 -204 and 205-214, 1978).

4)     Biodegradation study was conducted for 5 days for evaluating the percentage biodegradability of test substance Dipotassium 3,6 -dichloro-2 -(2,4,5,7 -tetrabromo-6 -oxido-3 -oxoxanthen-9 -yl)benzoate (CAS no. 6441 -77 -6) using standard dilution method at a temperature of 20°C. Sewage was used as a test inoculum. The 5 day BOD value of chemical Dipotassium 3,6 -dichloro-2 -(2,4,5,7 -tetrabromo-6 -oxido-3 -oxoxanthen-9 -yl)benzoate was determined to be 0 g/g. Thus, based on this value, Dipotassium 3,6 -dichloro-2 -(2,4,5,7 -tetrabromo-6 -oxido-3 -oxoxanthen-9 -yl)benzoate is considered to be not readily biodegradable in nature. (Sewage and Industrial Wastes, Vol. 27, No. 4, Pg. no. 1040-1053, 1955).

Adsorption

The adsorption coefficient Koc in soil and in sewage sludge dialuminium tris[2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6-tetrachlorobenzoate] (CAS No. 15876 -58 -1) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals (UERL, Report no. 15876-58-1/01/2017/Koc, 2017). The Log Koc value was determined to be 1.684 ± 0.035 at 25°C. This log Koc value indicates that the substance dialuminium tris[2 -(2,4,5,7 -tetrabromo-6 -oxido-3 -oxoxanthen-9 -yl)-3,4, 5,6 -tetrachlorobenzoate] has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

Bioaccumulation assessment

The tested substance does not fulfil the B criterion within Annex XIII based on the assessment that here follows:

The partition Coefficient n-octanol/water of dialuminium tris[2-(2,4,5,7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3,4,5,6-tetrachlorobenzoate](CAS No. 15876-58-1)was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 117 for testing of Chemicals. The Log Pow value was determineda to be 4.290 ± 0.020 at 25°C. The compound was therefore predicted to be of low concern for bioaccumulation in fish.  

 

Toxicity assessment

The tested substance does not fulfil the T criterion within Annex XIII based on the assessment that here follows:

 

CMR classification

The chemical unfulfilled the following classifications: H350, H372, H373, H340 and H360 based on assessment by PhD Martina Holst at SSS Europe AB, Sweden, 2017.

Ecotoxicity

The available EC50/LC50-values in freshwater species (all 3 trophic levels) are all above the CLP threshold for aquatic toxicity (i.e. 100 mg/L) except for algae. The EC50 in algae was determined to be 25 mg/L (Abitec, Prague, 2016). The chemical was therefore classified according to CLP category 3 for environmental hazard. More specifically, classified in ‘Acute category 3’ and ‘Chronic category 3’ (the chemical is not readily biodegradable).The fish LC50 was estimated to be above 100 mg/L and a long-term fish exposure assessment was therefore not required. Here follows a description of all the toxicity tests for CAS 1576-58-1:

 

1)     A fish acute toxicity test according to OECD Guideline 203 was conducted for dialuminium tris [2-(2, 4, 5, 7-tetrabromo-6-oxido-3-oxoxanthen-9-yl)-3, 4, 5, 6-tetrachlorobenzoate]. The nominal exposure concentration was 0.778 mg/L (i.e. the solubility limit of the tested chemical). The test organism was zebrafish (Danio rerio). One had two tanks per concentration and 4 fish per tank (8 fish in total per concentration). The water control contained the same number of fish. One observed no mortalities or abnormal behaviour in these fish tanks. The exposure time was 96 hours. The exposed fish were swimming a bit slower after 96 hours. However, no mortalities were observed in the exposure tanks. The LC50 was therefore predicted to be above 0.778 mg/L. The LC50 value was considered to be above the solubility limit of the tested chemical (UERL, Nagpur, 2016).

 

2)     An acute immobilisation test was used to test how a range of concentrations of CAS 15876-58-1 exerts different degrees of toxic effects on the swimming capability ofDaphnia magnaunder otherwise identical test conditions. The test was performed in close resemblance to OECD guideline 202 by ABITEC in Prague. The standardized protocol used to obtain the herein described results was by the testing laboratory referred to as “CSN EN ISO 6341”. The testing aim was to determine a EC50 after 48 hours of exposure toD. magna. The 48 hours EC50 was by the testing laboratory defined as the concentration estimated to immobilise 50 per cent of theDaphniaafter 48 hours of exposure. The stock solution used for the exposure assessment was prepared by dissolving dark red powder in reconstituted water. The stock solution was kept at 5 min in an ultrasonic bath. The test exposure concentrations were prepared by mixing the stock solution of the test sample with reconstituted water.Daphnidswere exposed to CAS 15876-58-1 in 50 ml beakers in a volume of 25 ml of liquid solution containing both the chemical and media as specified in OECD 202. The beakers were placed in a temperature controlled room at 20±1 degrees Celsius. TheD. magna(age ≤24) used for the test had been breed at ABITEC. The breeding stock ofD. magnaoriginated from University of Technology in Prague. The animals were exposed to medium (i.e.a beaker containing only medium) and/or the tested chemical during 48 hours (±1 hour). None of the exposed animal’s immobilization were affected by exposure to only medium. The nominal concentrations used were: 5, 10, 25, 50, 100 and 200 mg/L. There were 5Daphniaper test vessels and 4 replicates per concentration. The pH in test vessels were 7.5-7.8 mg/L. The positive control/reference substance used in the tested showed an expected result and gave a EC50 that corresponded to previous exposures with this chemical inD. magna. Immobilisation effects inD. mangaby chemical exposure was evident after 48 hours in exposure concentrations above 10 mg/L. The EC50 was defined as a concentration that immobilizes 50% of the exposedD. magna. The % of immobilization inD. magnaafter 48 hours of exposure to CAS 15876-39-8 were used in a nonlinear regression by Graphpad Software Prism 4.0 (San Diego, US). The EC50 was estimated based on the nonlinear regression. In conclusion, the EC50 for CAS 15876-58-1 was 152.3 mg/L (95% C.I: 108.7-213.4 mg/L) after 48 hours of exposure inD. magna(Abitec, Prague, 2016).

3)     The aim of a research study was to evaluate 48-hour Rose Bengal (read-across compound, CAS 632-68-8) exposure to the saltwater shrimp Artemia Salina. The method, setup and analytical method were not described in detail in the research article. A. salina eggs were stored at -20°C prior to experiments. Larvae were obtained by incubating eggs in petri dishes containing muslin-filtered sea water at 30°C for 24 hours. The larvae were separated from shells, dead larvae and unhatched eggs by their photo tactic movements toward a light source. One hade 20 to 30 larvae per petri dish/exposure concertation. Larvae were incubated at 30°C for up to 48 hours under static condition. The surviving larvae were at end of experiments counted (i.e. on counted moving larvae). The experiment was repeated 5 to 6 times. After 48 hours of exposure was the LC100 determined to be 10^-3M for Rose Bengal (approx. 1049.84 mg/L) (The Journal of Toxicological Sciences 2(4):383-390 1977).

4)     The aim of a research study was to evaluate 48-hour Phloxin (read-across compound, CAS 6441-77-6) exposure to the saltwater shrimpArtemia Salina. The method, setup and analytical method were not described in detail in the research article.A. salinaeggs were stored at -20°C prior to experiments. Larvae were obtained by incubating eggs in petri dishes containing muslin-filtered sea water at 30°C for 24 hours. The larvae were separated from shells, dead larvae and unhatched eggs by their photo tactic movements toward a light source. One hade 20 to 30 larvae per petri dish/exposure concertation. Larvae were incubated at 30°C for up to 48 hours under static condition. The surviving larvae were at end of experiments counted (i.e. on counted moving larvae). The experiment was repeated 5 to 6 times. After 48 hours of exposure was the LC100 determined to be 10^-3M for Phloxin (approx. 792.96 mg/L) (The Journal of Toxicological Sciences 2(4):383-390 1977).

 

5)     A freshwater algal growth inhibition exposure assessment was used to test how a range of concentrations of CAS 15876-58-1 exerts different degrees of toxic effects on the growth of Desmodesmus subspicatus under otherwise identical test conditions. The test was performed in close resemblance to OECD guideline 201 by ABITEC in Prague, Crez Republic. The standardized protocol used to obtain the herein described results was by the testing laboratory referred to as “CSN EN ISO 8692”. The 72 hours EC50 was by the testing laboratory defined as the concentration estimated to inhibit 50 per cent of the algae cell growth compared to unexposed cells after 72 hours of exposure. The nominal concentrations used for the exposure assessment were as follows: 5, 10, 20, 40 and 80 mg/L. The positive control/reference substance used in the tested showed an expected result and gave a EC50 that corresponded to previous exposures with this chemical inDesmodesmus subspicatus. After exposure was the EC50 calculated using nonlinear regression by the software Prism 4.0 (Graphpad Software, Inc., San Diego CA) In conclusion, the EC50 for CAS 15876-58-1 was 25.0 mg/L (95% C.I.: 19.5-32.1 mg/L) after 72 hours of exposure (ABITEC, Prague, 2016).

 

 

Overall conclusion about Persistence, Bioaccumulation and Toxicity (PBT).

 

Based on critical, independent and collective evaluation of only the information summarized herein (nothing else), the tested chemical substance only fulfils the P criterion within Annex XIII. Hence, the tested compound has not been classified as a PBT compound within Annex XIII.