5-oxo-1-(4-sulphophenyl)-2-pyrazoline-3-carboxylic acid

Endpoint summary

Additional information

Biodegradation

Biodegradation in water: screening tests

The predicted data for the test compoundPyrazolone T(CAS no. 118-47-8) and study of its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

Biodegradation in water ability was predicted (SSS QSAR prediction model, 2016) for the test substancePyrazolone T(CAS no. 118-47-8)using the SSS QSAR prediction model. The ready biodegradability of the test substancePyrazolone Twas estimated as 15.81% in 28 days by using CO2 evolution parameter. This result indicates thatPyrazolone Twas estimated to be not readily biodegradable in water.

 

Estimation Programs Interface Suite (EPI suite) was run to predict the biodegradation potential of the test compoundPyrazolone T(CAS no. 118-47-8). The screening test inherent to the biodegradability of the substance was calculated using the software BIOWIN v4.10. The results indicate thatPyrazolone Tis not expected to be readily biodegradable in nature.

 

Microbial decomposition of test chemical Food yellow 4 was carried out for 10 days (Yasuhide TONOGAI, 1978). The biodegradation of chemical was determined by 3 methods under aerobic conditions: Aerobic decomposition of dyes with sludge, Oxygen uptake and BOD determination. During 10 days of the aerobic experiment, the absorbance of dye solution was measured once day for 10 days. Only 20% decomposition of test chemical was obtained in10 days. 3.82 O2 mg/hg – sludge oxygen uptake was obtained in 5 –hrs test and the dissolved oxygen contents on the 5th day were essentially the same to initial ones. The low reactivity of aerobic sludge towards dyes was confirmed. Based on the results obtained from the aerobic degradation assay, Warburg method and BOD determination, it can be concluded that tartrazine is not expected to be readily biodegradable under aerobic conditions.

 

Biodegradation screening test (J-CHECK, 2016) was conducted for 28 days (4 weeks) for evaluating the percentage biodegradability of the test substance Edaravone. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l. The percentage degradation of test substance was found to be 0% by BOD, 2% by TOC and 28% by HPLC. Thus, the substance Edaravone is not expected to be not readily biodegradable in water.

 

On the basis of above results for target and read across substance, it can be concluded that the test substance is not expected to be readily biodegradable in nature.

Biodegradation in water and sediment: simulation tests

Estimation Programs Interface (EPI) Suite (2016) prediction model was run to predict the half-life in water and sediment for the test compound Pyrazolone T (CAS no. 118 -47 -8). Half-life of Pyrazolone T in water is estimated to be 15 days (360 hrs) while in sediment it is 134 days (3240 hrs). Based on these half-life value of Pyrazolone T, it is concluded that the chemical is not persistent in water but persistent in sediment.

Biodegradation in soil

Based on EPI prediction Level III Fugacity Model (EPI suite, 2016), the estimated half life period of Pyrazolone T in soil was obtained to be 30 days (720 hrs). Based on this half life value of Pyrazolone T, it is concluded that the chemical is not persistent in the soil environment.

On the basis of available information for the target substance, the test substance can be considered as not readily biodegradable in nature

Bioaccumulation

Bioaccumulation test was conducted for estimating the bioconcentration factor (BCF) of test substance Pyrazolone T.

The bioconcentration factor of Pyrazolone T was found to be 1.00 at pH 5.5 and 7.4 respectively.

Adsorption / desorption

Based on the Weight of evidence approach of adsorption endpoint for the target substance Pyrazolone T (Cas no. 118-47-8) studies are summarized as fallowed:

From EPI suite version 4.1 the adsorption capacity of the test chemical in soil was estimated using KOCWIN Program (v2.00) The koc was estimated using MCI method. KOC may be sensitive to pH.

First Order Molecular Connectivity Index = 8.787

Non-Corrected Log Koc (0.5213 MCI + 0.60) = 5.1803

Fragment Correction(s):

1 Nitrogen to non-fused aromatic ring = -0.5225

1 N-CO-C (aliphatic carbon) = -1.0277

* Organic Acid (-CO-OH) = -1.6249

1 Sulfonic acid (-S(=O)-OH) = -2.0000

Corrected Log Koc = 0.0052

Over Correction Adjustment to Lower Limit Log Koc = 1.0000

Estimated Koc = 10 L/kg

The estimated koc value for the test chemical is 10 L/kg

The test chemical has a log Koc of 1. Based on the classification criterion for PBT, the test chemical has negligible sorption to soil and sediment, rapid migration to ground water.

Other two predicted studies for target chemical from Scifinder and chemspider predicted database indicate that the adsorption coefficient (Koc) of test substance Pyrazolone T was found to be 10.

This Koc value suggests that Pyrazolone T is expected to have negligible sorption to soil and sediment.

While read across substance Tartrazine (Cas no. 1934-21-0) study from peer reviewed journal U.P.B. Sci. Bull., Series B, Vol. 78, Iss. 1, 2016 P.137-148 indicate that Soil adsorption test was conducted for test chemical tartrazine by using sorption floatation method.

Initial concentration of test chemical was 5-500 mg/L with pH range of 7-9 at temperature 20 deg C were selected to study tartrazine removal efficiency.

The removal efficiency of chemical tartrazine was found to be 9% using soil as adsorbent in sorption floatation technique.

Another peer reviewed study (Caliman Florentina Anca et al; Afinidad 66, no. 544 (2009)) for same read across i.e Tartrazine (Cas no. 1934-21-0) indicate that experiments were performed by using a natural soil sampled from the depth of 0-15 cm in the industrial area of the city of Iasi during the summer time (July 2008) that was previously dried and further screened to achieve soil particles size of above 2 mm, equilibration being carried-out with solution of CaCl2. For the equilibrium study, 50 ml Acid Yellow 23 of different concentrations were mixed with a dose of 12 g/L soil, the mixture being subjected to stirring at the room temperature as long it was needed to reach the equilibrium.The Freundlich, Langmuir and linear isotherm models were applied to describe the process and the parameters of these equations were calculated.

The sorption equilibrium revealed that the soil with particles higher than 2 mm may uptake 0.25 mg/g.

The sorption process is best represented by the Langmuir isotherm. The results reveal that the sorption of Acid Yellow 23 onto particles of soils follows a pseudo second order kinetics, suggesting that the chemisorption is the rate controlling mechanism.

The organic carbon normalized sorption coefficient KOC = 151.46 L/Kg. The very low value of KOC shows that the dye tend to remain in solution indicating also its very high mobility, since it is considered that sorption coefficients less than 500 indicate a considerable potential for losses through leaching. The low value of the organic carbon normalized sorption coefficient KOC suggests a high potential of leaching that could result in contamination of the groundwater.

Thus based on the above available predicted data for target and peer reviewed studies for resd across studies concluded that the test substance Pyrazolone T (Cas no. 118-47-8) expected to have negligible sorption to soil and sediment and may have potential to migrate towards groundwater.