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Biodegradation in water

Biodegradability of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS no. 10149 -98 -1) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 4.137% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated to be not readily biodegradable in water.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy) ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149-98-1). If released in to the environment, 35.5% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid in sediment is estimated to be 541.66 days (13000 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.0891%), indicates that 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid is not persistent in sediment.

 

Biodegradation in soil

The half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149 -98 -1) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 64.4% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid in soil is estimated to be 120 days (2880 hrs). Based on this half-life value of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Bioaccumulation: aquatic / sediment

BCFBAF model (v3.01) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the bioconcentration factor (BCF) of test chemical 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy) ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid (CAS No. 10149 -98 -1). The bioconcentration factor (BCF) of 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl] sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated to be 3.162 L/kg whole body w.w (at 25 deg C) which does not exceed the bio concentration threshold of 2000, indicating that the chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole- 3-carboxylic acid is not expected to bioaccumulate in the food chain.

Adsorption / desorption

KOCWIN model (v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid (CAS No. 11049 -98 -1). The soil adsorption coefficient i.e Koc value of 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated to be 11.76 L/kg (log Koc=1.0705) by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3- carboxylic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

Additional information

Biodegradation in water

Various predicted data for the target compound 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149-98-1) and supporting weight of evidence studies for its structurally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid(CAS No. 10149-98-1) was estimated.Test substance undergoes 4.137% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acidwas estimated to be not readily biodegradable in water.

 

In another prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid(CAS No. 10149-98-1) in the presence of mixed populations of environmental microorganisms was estimated.The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that chemical4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acidis expected to be not readily biodegradable.

 

In a supporting weight of evidence study from peer reviewed journal (Yasuhide 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 study 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 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 test 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.

 

Another biodegradation study was conducted for evaluating the percentage biodegradation of the same read across chemical C. I. Acid Yellow 23 (CAS no. 1934-21-0) (from peer reviewed journal Glenn M. Shaul et. al; 1991 and secondary source Glenn M. Shaul et. al; 1988). The study was carried out in 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 study. 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 chemical C. I. Acid Yellow 23was determined to be 103-107%,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 chemical C. I. Acid Yellow 23 was adsorbed at a level of˂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, chemical C. I. Acid Yellow 23 was can be considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (from OECD QSAR toolbox version 3.3 and EPI suite, 2017) and for its read across substance (from peer reviewed journals and secondary source), it can be concluded that the test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid can be expected to be not readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy) ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149-98-1). If released in to the environment, 35.5% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid in sediment is estimated to be 541.66 days (13000 hrs). However, as the percentage release of test chemical into the sediment is less than 1% (i.e, reported as 0.0891%), indicates that 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid is not persistent in sediment.

 

Biodegradation in soil

The half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149 -98 -1) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 64.4% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid in soil is estimated to be 120 days (2880 hrs). Based on this half-life value of 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is moderate to low.

On the basis of available information, the test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid can be considered to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data for the target compound 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149-98-1) and supporting weight of evidence study for its structurally similar read across substance were reviewed for the bioaccumulation end point which are summarized as below:

 

In aprediction done using theBCFBAF Program(v3.01) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the bioconcentration factor (BCF) of test chemical 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid (CAS No. 10149 -98 -1). The bioconcentration factor (BCF) of 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated to be 3.162 L/kg whole body w.w (at 25 deg C).

 

In an another prediction done by using Bio-concentration Factor (v12.1.0.50374) moduleACD (Advanced Chemistry Development)/I-Lab predictive module, 2017), theBio-concentration Factor (BCF) over the entire pH scale (pH 1 -14) of the test substance 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl] sulphonyl]phenyl]azo]-1 -(4 -sulpho phenyl)-1H-pyrazole-3 -carboxylic acid (CAS no. 10149 -98 -1) was estimated to be 1.

 

Bioconcentration Factor (BCF) of test chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated using Chemspider database(ChemSpider, 2017). The bioconcentration factor of test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated to be 1 at both pH 5.5 and 7.4, respectively.

 

Another predicted data was estimated usingSciFinder database (American Chemical Society (ACS), 2017) was used for predicting the bioconcentration factor (BCF) of test chemical 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl] sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid (CAS No. 10149 -98 -1). The bioconcentration factor (BCF) of 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl] sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid was estimated to be 1 (at 25 deg C).

 

In a supporting weight of evidence study from authoritative database (J-CHECK and HSDB, 2017 & EnviChem, 2014) for the read across chemical C. I. Acid Yellow 23 (Trisodium 5-hydroxy-1-(4-sulphophenyl)-4-(4-sulphophenylazo)pyrazole-3-carboxylate) (CAS no. 1934-21-0),bioaccumulation experiment was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of C. I. Acid Yellow 23.The study was performed according to other guideline "Bioaccumulation test of a chemical substance in fish or shellfish" provided in "the Notice on the Test Method Concerning New Chemical Substances", respectively. Cyprinus carpio was used as a test organism for the study. Test chemical nominal conc. used for the study were 0.6mg/land 0.06 mg/l, respectively. Range finding study involve the TLm (48 hr) ≥ 1000 mg/l on Rice fish (Oryzias latipes). Lipid content of the test organism was determined to be 2.8%. The bioconcentration factor (BCF value) of substance C. I. Acid Yellow 23 on Cyprinus carpio was determined to be ≤ 0.29 L/Kg at a conc. of 0.6 mg/l and ≤ 3.0 L/Kg at a conc. of 0.06 mg/l, respectively.

 

On the basis of above results for target chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (from EPI suite, ACD labs,ChemSpider and Scifinder,  2017) and for its read across substance from authoritative database (HSDB, EnviChem & J-CHECK), it can be concluded that the BCF value of test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid ranges from 1 – 3.162 which does not exceed the bioconcentration threshold of 2000, indicating that the chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid is not expected to bioaccumulate in the food chain.

Adsorption / desorption

Various predicted data for the target compound 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS No. 10149-98-1) and supporting weight of evidence study for its structurally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

In aprediction done using theKOCWIN Program(v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid (CAS No. 11049 -98 -1). The soil adsorption coefficient i.e Koc value of 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid was estimated to be 11.76 L/kg (log Koc=1.0705) by means of MCI method (at 25 deg C).

 

The Soil Adsorption Coefficient i.e Koc value of test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acide (CAS no. 10149 -98 -1) was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 1 (log Koc = 0) at pH range 1-14 respectively(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017).

 

In an another prediction done by using ChemSpider Database (2017),the Soil Adsorption Coefficient i.e Koc value of test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (CAS no. 10149 -98 -1) was estimated. The adsorption coefficient (Koc) value of test substance 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid was estimated to be 1 (Log Koc = 0) at pH 5.5 and 7.4, respectively.

 

Additional soil adsorption coefficient i.e Koc value of test chemical4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy) ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid (CAS No. 10149 -98 -1)was estimated using the SciFinder database (American Chemical Society (ACS), 2017). The soil adsorption coefficient i.e Koc value of 4,5 -dihydro-5 -oxo-4 -[[4 -[[2 -(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1 -(4 -sulphophenyl)-1H-pyrazole-3 -carboxylic acid was estimated to be 1 (log Koc = 0) (at 25 deg C).

 

In a supporting weight of evidence study from experimental study report (Sustainability Support Services (Europe) AB, Report no. UERL/PC/010-03, 2017) for the read across chemical 3,4-dimethylaniline (CAS no. 12225-21-7),the adsorption coefficient Koc in soil and in sewage sludge of read across chemical aluminum tris(4-{[3-carboxy-5-oxo-1-(4-sulfophenyl)-4,5-dihydro-1H-pyrazol-4-yl]diazenyl}benzenesulfonate) (CAS No. 12225-21-7) 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 3 mg of test item and diluted with methanol up to 10ml. Thus, the test solution concentration was 300 mg/l. The pH of test substance was 6.71. 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 were chosen according to functional similarity with the test substance and calibration graph prepared. The reference substances were 2-nitrophenol, nitrobenzene, 4-nitrobenzamide, N, N-dimethylbenzamide, N-methylbenzamide and benzamide having Koc value ranging from 1.239 to 2.47. The Log Koc value of test chemical aluminum tris(4 -{[3 -carboxy-5 -oxo-1 -(4 -sulfophenyl)-4,5 -dihydro-1H-pyrazol-4 -yl]diazenyl}benzenesulfonate) was determined to be 0.7040 ± 0.01 at 25°C.

 

On the basis of above overall results for target chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid (from EPI suite, ACD labs,ChemSpider and Scifinder,2017) and for its read across substance from study report (UERL study report, 2017), it can be concluded that the Koc value of test substance 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid ranges from1– 11.76, indicating that the test chemical 4,5-dihydro-5-oxo-4-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]-1-(4-sulphophenyl)-1H-pyrazole-3-carboxylic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.