Disodium [5-chloro-3-[[4,5-dihydro-3-methyl-5-oxo-1-(3-sulphophenyl)-1H-pyrazol-4-yl]azo]-2-hydroxybenzene-1-sulphonato(4-)]hydroxychromate(2-)

Endpoint summary

Description of key information

Biodegradation in water

Biodegradation study was carried out for 42 days for evaluating the percentage biodegradation of the test chemical Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) (CAS no. 6408 -31 -7) using modified OECD Guideline 302B (U. Pagga and O. Brown, 1986). Activated sludge was used as a test inoculum.The sources of the activated sludge were treatment plants conveniently located to the laboratories carrying out the test.These treatment plants received communal and/or industrial wastewater.Concentration of inoculum i.e, activated sludge used was 0.5 g/l and initial test substance conc. used in the study was 100 mg/l. Analytical methods involve the measurement of extinction at absorption maximum 412 nm and DOC (dissolved organic carbon). The percentage degradation of the test substance Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) was determined to be 28% by using DOC removal parameter in 42 days. Thus, based on percentage degradation, the chemical Disodium [5-chloro-3-[[4,5-dihydro-3-methyl-5-oxo-1-(3-sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) was considered to be not readily biodegradable in nature.

Additional information

Biodegradation in water

Various experimental studies for the target compound Disodium [5-chloro-3-[[4,5-dihydro-3-methyl-5-oxo-1-(3-sulphophenyl)-1H-pyrazol-4-yl]azo]-2-hydroxybenzene-1-sulphonato(4-)]hydroxychromate(2-)(CAS No. 6408-31-7) and supporting study for its structurally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study from peer reviewed journal (U. Pagga and O. Brown, 1986), biodegradation experiment was carried out for 42 days for evaluating the percentage biodegradation of the test chemical Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) (CAS no. 6408 -31 -7) using modified OECD Guideline 302B. Activated sludge was used as a test inoculum.The sources of the activated sludge were treatment plants conveniently located to the laboratories carrying out the test.These treatment plants received communal and/or industrial wastewater.Concentration of inoculum i.e, activated sludge used was 0.5 g/l and initial test substance conc. used in the study was 100 mg/l. Analytical methods involve the measurement of extinction at absorption maximum 412 nm and DOC (dissolved organic carbon). The percentage degradation of the test substance Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) was determined to be 28% by using DOC removal parameter in 42 days. Thus, based on percentage degradation, the chemical Disodium [5-chloro-3-[[4,5-dihydro-3-methyl-5-oxo-1-(3-sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) was considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 48 hrs for evaluating the percentage biodegradability of test substance Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) (CAS no. 6408 -31 -7) by using different species of Pseudomonas under anaerobic conditions at a temperature of 28°C (ForP. oleovorans and P. putida) and 37°C (For P. aeruginosa), respectively (E. Silveira, et. al; 2009).  Pseudomonas aeruginosa, Pseudomonas oleovorsans and Pseudomonas putida were used as a test inoculum for the study. The microorganisms were obtained from the collections of Antibiotics Institute of the Federal University of Pernambuco and the Brazilian Collection of Industrial and Environmental Microorganisms (CBMAI) of the State University of Campinas, previously identified as Pseudomonas aeruginosa (ATCC 27853), Pseudomonas oleovorans (CBMAI 703) and Pseudomonas putida (ATCC 17514). The microorganisms were preserved in cryotubes containing glass beads and 10% glycerol (v/v). Each cryotube was loaded from the same initial culture and had an average of 30 beads. It was thus possible to use the same cell generation for all experiments. Initial cell/biomass concentration of test inoculum was approx. 0.312 g/l dry weight of cells and initial test substance conc. used in the study was 50 mg/l, respectively. For each experiment, an Erlenmeyer flask containing 20 ml of Nutrient Broth (meat extract 3 g/l and peptone 5 g/l) was inoculated with a single glass bead from the same crytobe and incubated at the maintenance temperature for each microorganism (28°C for P. cepacia, P. oleovorans, and P. putida or 37°C for P. aeruginosa) for 24 h when an early stationary phase or final exponential phase was reached. 4 different Pseudomonas spp. were screened before using for the decolorization study. For this, the strains cultivated in a liquid culture were streaked on plates and incubated for 96 h with different dyes as the single carbon source (1 g/l) in a Minimal Mineral Medium, MMM (NaCl 7 mg/l; CaCl2.2H2O 4 mg/l; MgSO4.7H2O 2 mg/l; and bacteriological agar 3 g/l) and the pH adjusted to 7.0.The dyes were filter-sterilised on a 0.2mm filter prior to addition to the sterile culture medium. Decolorization study was done by adding 1 ml of fresh 24 -h-old cultures (approx. 0.312 g/l of dry weight of cells) to 10 ml sterile liquid medium in a 20 ml test tube. The tubes were incubated under static anoxic conditions away from light. The samples from the decolourization cultures were collected and analysed. As all samples contained biomass and dye, concentration of biomass (first and second step) and dye (third step) were evaluated. Control experiments were performed using the same medium without microorganisms or dyes. Methyl orange was used as a standard dye for the study. P. aeruginosa achieved the highest colour removal rate, removing over 97% of the colour from the standard dye (methyl orange). The percentage decolourization of test substance Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) was determined to be 52% and approx. 15% by using three different strains i.e;Pseudomonas aeruginosa, Pseudomonas oleovorsans and Pseudomonas putidaafter 48 hrs. Thus, based on percentage decolorization, Disodium [5 -chloro-3 -[[4,5 -dihydro-3 -methyl-5 -oxo-1 -(3 -sulphophenyl)-1H-pyrazol-4 -yl]azo]-2 -hydroxybenzene-1 -sulphonato(4 -)]hydroxychromate(2 -) is considered to undergoe primary degradation in water and thus can be expected to be biodegradable in nature.

 

In a supporting study from peer reviewed journal (HYasuhide TONOGAI, et. al; 1978) for the read across chemical Trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4 -sulphophenylazo)pyrazole-3 -carboxylate (CAS no. 1934-21-0), biodegradation experiment was conducted under aerobic conditions for evaluating the percentage biodegradability of read across substance Trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4-sulphophenylazo)pyrazole-3-carboxylate (CAS no. 1934-21-0). Activated sludge was used as a test inoculum obtained from the municipal sewage treatment plant, Nakahama, Osaka.The return sludge was acclimated to the synthetic sewage for a week or longer, and it was used for the aerobic and anaerobic decomposition experiments. Synthetic sewage was prepared by dissolving Glucose, peptone and potassium dihydrogen phosphate, 30g each, in 1 liter water and the pH was adjusted to pH 7.0 with sodium hydroxide. Concentration of inoculum used for the study was3000 mg/l. Percentage degradation of chemical was determined by measuring the absorbance (test material analysis), oxygen uptake and BOD parameter. For the aerobic decomposition of dyes with sludge, 250 ml of O.03 M dye solution was added to 750ml of sludge (MLSS ca, 3,000 ppm), 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 whereas measurement oxygen uptake by sludge involve 2.0 ml of sludge, 0.2 ml of 1,000 ppm dye solution, and O.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 the the by dye addition. For determining the BOD values, test chemical solutions (10, 20 and 40 ppm) were prepared with the seeded dilution water and kept at 20°C. The dissolved oxygen contents were then measured by using a dissolved oxygen meter. The percentage degradation of read across chemical Trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4-sulphophenylazo)pyrazole-3-carboxylatewas determined to be 20% in 10 days by using the test material analysis parameter. From the oxygen uptake by Warburg’s manometer, the low activity of the sludge to dye was obtained and by using the dissolved oxygen meter, the dissolved oxygen contents on the 5th day were essentially the same to initial ones. Thus, based on percentage degradation, the chemical Trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4-sulphophenylazo)pyrazole-3-carboxylatewas considered to be not readily biodegradable in nature.

 

On the basis of above results from experimental studies for target chemical Disodium [5-chloro-3-[[4,5-dihydro-3-methyl-5-oxo-1-(3-sulphophenyl)-1H-pyrazol-4-yl]azo]-2-hydroxybenzene-1-sulphonato(4-)]hydroxychromate(2-) (from peer reviewed journals) and for its read across substance (from peer reviewed journal), it can be concluded that the test substance Disodium [5-chloro-3-[[4,5-dihydro-3-methyl-5-oxo-1-(3-sulphophenyl)-1H-pyrazol-4-yl]azo]-2-hydroxybenzene-1-sulphonato(4-)]hydroxychromate(2-) can be expected to be not readily biodegradable in nature.