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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation:

Biodegradation in water

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the percentage degradation of the test chemical is expected to be range from 0 to 57%, respectively in 56 days. Thus, based on this, test chemical is considered to be not readily biodegradable in nature

Additional information

Biodegradation:

Biodegradation in water

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the biodegradability of the test chemical . The studies are as mentioned below:

Biodegradation study was carried out to determine the biodegradability rate of the test chemical. Activated sludge was used as an inoculum and the study was performed under anaerobic conditions at a temperature of 35°C for a period of 56 days.Samples of the aqueous phase were analyzed either qualitatively or quantitatively by an appropriate chromatographic method for the presence of certain of the expected aromatic amine metabolites.The percentage degradation of test substance was determined to be 57% by appropriate chromatography method in 56 days. The metabolites identified by theappropriate chromatographic method were 3 -amino-6 -methylbenzene- N-phenylsulphonamid and 4 -amino-3 -methy1 -1 -[4'-sulphophenyl)pyrazolone, respectively. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

Another biodegradation study was conducted for evaluating the percentage biodegradation of test chemical. The study was carried outin pilot activated sludge process system using several wastewater and mixed liquor at a temperature of 21-25°C and pH range of 7.0-8.0, respectively. Mass balance calculations were made to determine the amount of the dye compound in the waste activated sludge (WAS) and in the activated sludge effluent (ASE). Activated sludge was used as test inoculum for the study. Test chemical conc. used for the study was 1 and 5 mg/l, respectively.Screened raw wastewater from the Greater Cincinnati Mill Creek Sewage Treatment Plant was used as the influent (INF) to three pilot-scale activated sludge biological treatment systems (two experimental and one control) operated in parallel. Each system consisted of a primary clarifier (33 L), complete-mix aeration basin (200 L), and a secondary clarifier (32 L). Each water soluble dye was dosed as commercial product to the screened raw wastewater for the two experimental systems operated in parallel at targeted active ingredient doses of 1 and 5 mg/L of influent flow (low and high spike systems, respectively). All systems were operated for at least three times.All samples were 24 hr composites made up of 6 grab samples collected every 4 hr and stored at 4°C. The possible removal mechanisms for a dye compound in the ASP system include adsorption, biodegradation, chemical transformation, photodegradation, and air stripping.Dye analytical recovery studies were conducted by dosing the purified dye compound into organic-free water, influent wastewater, and mixed liquor. These studies were run in duplicate and each recovery study was repeated at least once to ensure that the dye compound could be extracted. Purified dye standards were analytically prepared from the commercial dye product by repeated recrystallization. The INF, primary effluent (PE), and ASE were filtered, and the filtrate was passed through a column packed with resin. The filter paper and resin were soaked in an ammonia-acetonitrile solution and then Soxhlet extracted with ammonia-acetonitrile. The extract was concentrated and brought up to 50 mL volume with a methanol/dimethylformamide solution. The mixed liquor (ML) samples were separated into two components, the filtrate or soluble (SOL) fraction and the residue (RES) fraction. The SOL fraction was processed similar to the INF, PE, and ASE samples. The RES fraction and the filter paper were processed similar to these samples but the resin adsorption step was omitted. All extracted samples were analyzed by HPLC with an ultraviolet-visible detector. Total suspended solids (TSS) analyses were also performed on the INF, PE, ML, and ASE samples.Percentage recovery of test chemical was determined to be 98-101%,thus, it appeared that little or no chemical transformation occurred for test chemical because of contact with the variable wastewater and/or sludge matrix under these conditions. Also it was evaluated that the test chemical was adsorbed at a level of 1 -<1% on the ML solids, indicating that the compound was substantially untreated by the activated sludge process (ASP). Thus, based on % recovery of test chemical was can be considered to be not readily biodegradable in nature.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the percentage degradation of the test chemical can be expected to be range from 0 to 57%, respectively in 56 days. Thus, based on this, test chemical is considered to be not readily biodegradable in nature.