4-chlorobenzophenone

Endpoint summary

Description of key information

Hydrolysis: On the basis of the experimental studies of the structurally similar read across chemical and applying the weight of evidence, the half life DT50 value of test chemical was determined to be > 27 to < 120 years.

 

Biodegradation in water: screening test: The test chemical undergoes 32.71 % biodegradation after 42 days in the test condition. Thus, the test item was considered to be not readily biodegradable in water.

 

Biodegradation in water: simulation testing on ultimate degradation in surface water: Estimated half life of test chemical in water was 37.5 days, 900 hr. 

 

Biodegradation in sediment: simulation tests: Estimated half life of test chemical in sediment estimated to be 337.5 days, 8100 ( hr).

 

 Biodegradation in soil: Biodegradation half-life of test substance in soil was estimated to be 75 days, 1800 hrs.

 

Adsorption/ Desorption: 

The Adsorption Coefficient of test substance was determined as per the HPLC method (OECD Guideline-121). The Log Koc value was observed to be 3.966 ± 0.013 at 25°C

Additional information

Hydrolysis: 

Data available of the structurally similar read across chemicals has been reviewed to determine the half life DT50 of the test chemical. The studies are as mentioned below:

 

The first study of hydrolysis in water was carried out. Test conditions includes pH of 7 and temperature of 25 °C. The half-life of DT50 value of test chemical was determined to be 27 years at pH 7 and 25 °C. As per the value of DT50 the test chemical was considered to be stable in water. 

 

The second study of hydrolysis in water was carried out. Test conditions includes pH of 3,5 and temperature of 27 °C. The half-life of DT50 value of test chemical was determined to be 120 years at pH 3,5 and 27 °C. As per the value of DT50 the test chemical was considered to be stable in water. 

 

On the basis of the experimental studies of the structurally similar read across chemical and applying the weight of evidence, the half life DT50 value of test chemical was determined to be > 27 to < 120 years. As per the value of DT50 the test chemical was considered to be stable in water. 

 

Biodegradation in water: screening test: 

 

Different experimental studies for the Biodegradation in water endpoint were reviewed for the test substance  and are summarised below:

 

The first study includes 42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C under aerobic conditions. The test system included control, test item, reference item and toxicity control. Polyseed were used for this study. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 1 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD42 value of test chemical was observed to be 0.70 mgO2/mg. ThOD was determined by calculation as 2.14 mgO2/mg. % degradation was calculated using the values of BOD and ThOD for test item and was determined to be 32.71 % at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was determined to be 55.42 % on 7th day which exceeds as 70.48 % on 42nd day. The activity of the inoculum is thus verified and the test can be considered as valid. Oxygen depletion in the inoculum blank did not exceed 1.5 mg dissolved oxygen/L after 28 days. The residual conc. of oxygen in test bottles did not fall below 0.5 mg/L at any time, % degradation of reference compound has reached the pass levels (60% of ThOD) by day 14 and in a toxicity test, containing both the test substance and a reference compound, >25% biodegradation occurred within 14 days, test substance cannot be assumed to be inhibitory. Thus, fulfilling the validity crtieria as per OECD test guideline and hence, study is considered to be valid. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 32.71 %. Based on the results, the test chemical, under the test conditions, was considered to be not readily biodegradable in water.

 

The second study includes Estimation Programs Interface Suite was run to predict the biodegradation potential of the test compound in the presence of mixed populations of environmental microorganisms. 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 biodegradability of the substance was calculated using seven different Biowin 1-7 models of the BIOWIN v4.10 software. The half life DT50 value of test chemical was estimated to be 2.5133 months. The results indicate that the test chemical is expected to be not readily biodegradable in water. 

 

The third study of biodegradation in water was carried out. The duration of study was 28 days. Activated sludge was taken as inoculum. The concentration of sludge was taken as 30 mg/l. The concentration of test chemical was taken as 100 mg/l. The study design was of standard type. The percent biodegradation of test chemical was determined to be 4 and 0 % based on O2 consumption parameter and HPLC method respectively in duration of 28 days. As per the value of percent biodegradation the test chemical was consider as not readily biodegradable in water. 

 

The fourth  study of biodegradation in water was carried out. The duration of study was 14 days. Activated sludge was taken as inoculum. The concentration of sludge was taken as 30 mg/l. The concentration of test chemical was taken as 100 mg/l. The percent biodegradation of test chemical was determined to be 0 and 3 % based on O2 consumption parameter and GC method respectively in duration of 14 days. As per the value of percent biodegradation the test chemical was consider as not readily biodegradable in water. 

 

On the basis of the above-mentioned information, the test chemical was considered as 'not readily biodegradable' in water. 

 

Biodegradation in water: simulation testing on ultimate degradation in surface water: 

Estimation Programs Interface prediction model was run to predict the half-life in water for the test compound. If released in to the environment, 16.9 % of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 37.5 days ( 900 hrs). The half-life ( 37.5 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is moderate to low.

 

 

Biodegradation in sediment: simulation tests: 

Estimation Programs Interface prediction model was run to predict the half-life in sediment for the test compound. The half-life period of test chemical in sediment is estimated to be  337.5 days, 8100 ( hr). Based on this half-life value, it indicates that test chemical is persistent in sediment.

 

Biodegradation in Soil: 

The half-life period of test chemical in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment,  80  % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical in soil is estimated to be 75 days (  1800  hrs). Based on this half-life value of test chemical, 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.

 

Adsorption/ Desorption: 

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

 

The first study of adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. A test item solution was prepared by accurately weighing 5 mg of test item and diluted with methanol up to10 ml.Thus, the test solution concentration was 500 mg/l. The pH of test substance was 7.05. Each of the reference substance and test substance were analysed by HPLC at 210 nm. For the HPLC method, HPLC model no. Agilent Technologies,1260 Infinity II was used. Column used was  ZORBAX Eclipse Plus C18, 4.6×100mm, 3.5 μm. Acetonitrile: water (55:45) was used as a mobile phase. During the study, flow rate was 1.0ml/min. Study was performed at a temperature of 25°C. Injector volume was 10μl. Chem Station Open lab Control Panel was used as a data Acquisition software and detector wavelength taken for the study was 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'. 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 estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were 4-chloroaniline, 4 -methylaniline(p-Tolouidine), N-methylaniline, 2 - nitrophenol, Nitrobenzene, 4-Nitrobenzamide, N,Ndimethylbenzamide, N-methylbenzamide, Benzamide having Koc value ranging from 1.239 to 2.47. The Adsorption Coefficient of test substance was determined as per the HPLC method (OECD Guideline-121). The Log Koc value was observed to be 3.966 ± 0.013 at 25°C. This log Koc value indicates that the test chemical has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

The second study of Soil Adsorption Coefficient i.e. Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 1824 L/kg (log Koc= 3.26 ) by means of MCI method at 25 °C.  This log Koc value indicates that test chemical has moderate sorption to soil and therefore test chemical has slow migration potential to groundwater.

 

The third study was carried out using a structure estimation method based on molecular connectivity indices the Koc of test chemical was determined to be 950 (log Koc = 2.97). This log Koc value indicates that test chemical has moderate sorption to soil and therefore test chemical has slow migration potential to groundwater.

 

The fourth study of adsorption was carried out. The adsorption coefficient Koc value of test chemical was determined to be 1200 dimensionless (log Koc = 3.08 ). This log Koc value indicates that test chemical has moderate sorption to soil and therefore test chemical has slow migration potential to groundwater.

On the basis of the above-mentioned information, the test chemical has strong to moderate sorption to soil and therefore test chemical has slow to negligible migration potential to groundwater.