4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one

Endpoint summary

Description of key information

Biodegradation in water

Biodegradability of 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS no. 6407 -78 -9) is predicted using QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 5.68% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was estimated to be not readily biodegradable in water.

Bioaccumulation: aquatic / sediment

The bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one (CAS no.6407 -78 -9) (INERIS Database, 2009). The BCF (bioaccumulation factor) value of chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol- 5 -one was estimated to be 10 dimensionless, which does not exceed the bioconcentration threshold of 2000, indicating that the chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one is considered to be non-accumulative in aquatic organisms.

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 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one (CAS no. 6407 -78 -9). The soil adsorption coefficient i.e Koc value of 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one was estimated to be 14680 L/kg (log Koc=4.1669) by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4-[(E)-2 -(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

Additional information

Biodegradation in water

Various predicted data for the target compound 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No. 6407-78-9) 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 chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one(CAS No. 6407-78-9) was estimated.Test substance undergoes 5.68% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-onewas 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 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one(CAS No. 6407-78-9) 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 chemical 4 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-oneis expected to be not readily biodegradable.

 

For the target chemical (CAS no. 6407-78-9) from secondary source (Environment Canada (EC) Health Canada (HC), 2016), biodegradability of test substance 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one (CAS no.6407-78-9) was estimated using the BIOWIN Sub-models 3-6 and CATALOGIC model under aerobic conditions. The percentage degradation of chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was evaluated to be 0.56 -12.2% estimated by using the CATALOGIC model and on the basis of the output result of the BIOWIN Sub-models 3 -6, it indicates that chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one biodegrades slowly. Thus, based on this, test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one is considered to be not readily biodegradable in nature.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017) for the read across chemical 1-Phenyl-3-methyl-5-pyrazolone (CAS no. 89-25-8),biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of read across substance 1-Phenyl-3-methyl-5-pyrazolone. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of read across substance 1 -Phenyl-3 -methyl-5 -pyrazolone was determined to 0, 2 and 28% by BOD, TOC removal and HPLC parameter in 28 days. Thus, based on percentage degradation, 1-Phenyl-3-methyl-5-pyrazolone is considered to be not readily biodegradable in nature.

 

Another biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of another read across substance 1,2-bis(2-methylphenyl)guanidine (CAS no. 97-39-2) (J-CHECK, 2017 and secondary source OECD SIDS, 2007). The study was performed according to OECD Guide-line 301 C "Ready Biodegradability: Modified MITI Test under aerobic conditions. Activated sludge, non-adapted was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. Aniline was used as a reference substance for the study. Reference substance aniline undergoes 77 and 79% degradation after 14 and 28 days, respectively. The percentage degradation of substance 1,2 -bis(2 -methylphenyl)guanidine was determined to 1 and 0% by BOD and HPLC parameter in 28 days. Thus, based on percentage degradation,1,2-bis(2-methylphenyl)guanidine is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one(from OECD QSAR toolbox version 3.3, EPI suite, 2017 and secondary source, 2016) and for its read across substance (from authoritative database J-CHECK and secondary source OECD SIDS), it can be concluded that the test substance 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-onecan be expected to be not readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Various predicted data and experimental study for the target compound 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No. 6407-78-9) 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 an experimental study from authoritative database (INERIS Database, 2009), bioaccumulation study was conducted for estimating the BCF (bioaccumulation factor) value of test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one(CAS no. 6407 -78 -9). The BCF (bioaccumulation factor) value of chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol- 5 -one was estimated to be 10 dimensionless.

 

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 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one (CAS No. 6407 -78 -9). The bioconcentration factor (BCF) of 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was estimated to be 10 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) of the test substance 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H- pyrazol-5 -one (CAS no. 6407 -78 -9) was estimated to be 5.90, 35.8, 126, 171, 177 and 178 at pH range 0, 1, 2, 3, 4 and 5-14, respectively.

 

Bioconcentration Factor (BCF) of test chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one was estimated using Chemspider database(ChemSpider, 2017). The bioconcentration factor of test substance 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one was estimated to be 371.27 at pH 5.5 and 371.32 at pH 7.4, respectively.

 

Another predicted data was estimated using SciFinder database (American Chemical Society (ACS), 2017) was used for predicting the bioconcentration factor (BCF) of test chemical 4-[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one (CAS No. 6407 -78 -9). The bioconcentration factor (BCF) of 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one was estimated to be 77.9, 228, 284, 291 and 292 at pH range 1, 2, 3, 4-6 and 7-10, respectively (at 25 deg C).

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2017 & EnviChem, 2014) for the read across chemical 2',3-Dimethyl-4-(2-hydroxynaphthylazo)azobenzene (CAS no. 85-83-6),bioaccumulation experiment was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of 2',3-Dimethyl-4-(2-hydroxynaphthylazo)azobenzene (CAS no. 85-83-6). 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 0.35mg/l and 0.035 mg/l, respectively. Test chemical solution was prepared in HCO-40 or crystal sugar. Analytical method involve the recovery ratio: Test water : 1st concentration area : 97.3 %, 2nd concentration area : 94.5 %, Fish : 76.1 %, - Limit of detection : Test water:1st concentration area : 100 %, 2nd concentration area : 98.6 %, Fish : 90.8 %, - Limit of detection : Fish : 0.103 ppm. Range finding study involve the TLm (48 hr) ≥ 100 mg/l (w/v) on Rice fish (Oryzias latipes).The bioconcentration factor (BCF value) of substance 2',3-Dimethyl-4-(2-hydroxynaphthylazo)azobenzene on Cyprinus carpio was determined to be in the range of 0.29 – 2.9 L/Kg at a conc. of 0.35 mg/l and 2.9 – 11 L/Kg at a conc. of 0.035 mg/l, respectively.

 

For the read across chemical 4,4'-(1E,1'E)-(3,3'-dichlorobiphenyl-4,4'-diyl)bis(diazene-2,1-diyl)bis(3-methyl-1-phenyl-1H-pyrazol-5(4H)-one) (CAS no. 3520-72-7), bioaccumulation study was conducted on test organism Cyprinus carpio for 6 weeks for evaluating the bioconcentration factor (BCF value) of 4,4'-(1E,1'E)-(3,3'-dichlorobiphenyl-4,4'-diyl)bis(diazene-2,1-diyl)bis(3-methyl-1-phenyl-1H-pyrazol-5(4H)-one) (J-CHECK, 2017 & EnviChem, 2014). 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 0.15mg/land 0.015 mg/l, respectively. Test chemical solution was prepared in HCO-20 or crystal sugar. Analytical method involve therecovery ratio: Test water : 1st concentration area: 91.0 %, 2nd concentration area : 99.9 %, Fish : 87.9 %, - Limit of detection : Fish : 0.04 ppm. Range finding study involve the TLm (48 hr) ≥ 100 mg/l (w/v) on Rice fish (Oryzias latipes).The bioconcentration factor (BCF value) of substance 4,4'-(1E,1'E)-(3,3'-dichlorobiphenyl-4,4'-diyl)bis(diazene-2,1-diyl)bis(3-methyl-1-phenyl-1H-pyrazol-5(4H)-one)on Cyprinus carpio was determined to be in the range of 0.75 – 5.6 L/Kg at a conc. of 0.15 mg/l and ≤ 2.8 L/Kg at a conc. of 0.015 mg/l, respectively.

 

On the basis of above overall results for target chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one(from secondary source, EPI suite, ACD labs,ChemSpider and Scifinder,2017) and for its read across substance from authoritative database (J-CHECK, 2017 & EnviChem, 2014), it can be concluded that the BCF value of test substance 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one ranges from10– 371.27, which does not exceed the bioconcentration threshold of 2000, indicating that the chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one is not expected to bioaccumulate in the food chain.

Adsorption / desorption

Various predicted data for the target compound 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (CAS No. 6407-78-9) 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 -[(E)-2 -(2,4 -dimethylphenyl) diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5 -one (CAS no. 6407 -78 -9). The soil adsorption coefficient i.e Koc value of 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-one was estimated to be 14680 L/kg (log Koc=4.1669) by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4-[(E)-2 -(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

In a supporting study from secondary source (Environment Canada (EC) Health Canada (HC), 2016), adsorption study was conducted for estimating the adsorption coefficient (Koc) value of test chemical 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H- pyrazol-5 -one (CAS no.6407 -78 -9). The adsorption coefficient (Koc) value was calculated using a model. The adsorption coefficient (Koc) value of test substance 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1 -yl]-3 -methyl-1 -phenyl-4,5 -dihydro-1H-pyrazol-5-onewas estimated to be 31622.77 dimensionless (Log Koc = 4.5). This Koc value indicates that the substance 4 -[(E)-2 -(2,4 -dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one has a very strong sorption to soil and sediment and therefore have negligible migration potential to ground water.

 

On the basis of above overall results for target chemical 4 -[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one (from EPI suite,2017 and secondary source, 2016), it can be concluded that the Koc value of test substance 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one ranges from 14680–31622.77,indicating that the test chemical 4-[(E)-2-(2,4-dimethylphenyl)diazen-1-yl]-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazol-5-one has a strong to very strong sorption to soil and sediment and therefore have slow to negligible migration potential to ground water.