Butylhydroxyoxostannane

Endpoint summary

Description of key information

Hydrolysis

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical Butylstannonic acid can be expected to be range from  > 5 to 40 days, respectively. Thus, based on this, test chemical Butylstannonic acid is considered to be not hydrolysable in water.

Biodegradation in water

Estimation Programs Interface Suite (2017) was run to predict the biodegradation potential of the test compound Butylstannonic acid (CAS no. 2273 -43 -0) 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 results indicate that chemical  Butylstannonic acid is expected to be not readily biodegradable.

Biodegradation in water and sediment

Estimation Programs Interface (2017) prediction model was run to predict the half-life in water and sediment for the test compound Butylstannonic acid (CAS No. 2273 -43 -0). If released in to the environment, 26 % 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 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of test chemical Butylstannonic acid in sediment is estimated to be 135 days (3240 hrs). However as the percentage release of test chemical into sediment is less than 1 %(i.e., reported as 0.249) indicates that test chemical Butylstannonic acid is not persistent in sediment as well.

Biodegradation in soil

The half-life period of test chemicalButylstannonic acid(CAS No.2273 -43 -0) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2017). If released into the environment, 72.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemicalButylstannonic acidin soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemicalButylstannonic acid, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

Bioaccumulation : aquatic/sediments:

Using BCFBAF Program (v3.00) model of EPI suite 2017 the estimated bio concentration factor (BCF) for Butylstannonic acid (CAS No.2273-43-0) is 100 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical Butylstannonic acid is non bioaccumulative in food chain.

Adsorption / desorption

The Soil Adsorption Coefficient i.e Koc value of  test chemical Butylstannonic acid (CAS No:2273-43-0) was estimated using EPI suite KOCWIN Program (v2.00) as 201.6 L/kg (log Koc= 2.3045)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance Butylstannonic acid has lowsorption to soil and sediment and therefore hasmoderate migration potential to groundwater.

Additional information

Hydrolysis

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the half-life of the test chemical Butylstannonic acid.The studies are as mentioned below:

The half-life of the test chemical was determined at different pH range. The study was performed according toOECD Guideline 111 (Hydrolysis as a Function of pH) at a temperature of 50°C. Initial test substance concentration used for the study was 106.3 mg/l. Stock solutions containing approximately 10 mg test substance/10 ml methanol were made. 100 µl of the stock solution was added to a vial. Subsequently, 10.0 ml of sterilized buffer solution pH 4.0, 7.0, or pH 9.0, or 10.0 ml of sterilized Milli-Q water was added to the vial. Each vial was closed with a crimpcap closure. The vials were kept at 50°C for 5 days. Quality Control (QC) samples were prepared in duplicate on each day of analysis of the hydrolysis solutions, by adding a stock solution of the substance in methanol to 12.5 ml Milli-Q water. The concentration of the QC samples was approximately 80 mg/l, which corresponds to the initial concentration of the hydrolysis solutions (i.e., 106.3 mg/l in 10.0 ml, diluted to 12.5 ml during the derivatization and extraction procedure). To each QC sample, an aliquot of internal standard solution (monoheptyltin trichloride, diheptyltin dichloride, tripropyltin chloride, and tetrapropyltin in methanol) was added and each sample was derivatized with STEB, extracted and analyzed using GC-MS. The concentration of the test substance was determined at t = 0 and t = 5 days, plus one intermediate point in time, t = 1 day. For each pH, the percent hydrolysis after 5 days was calculated from the test substance concentrations measured at t = 0 and t = 5 days. The sterility tests performed at the end of the hydrolysis tests did not show any bacterial activity. Biodegradation of the test substance in the hydrolysis solutions did not occur. The percentage hydrolysis was calculated as: [(mean concentration (mg/l) at t = 5 days - mean concentration (mg/l) at t = 0) / (mean concentration (mg/l) at t = 0)] * 100%. The percentage hydrolysis of the test substance (analyzed after derivatization with STEB to the corresponding tetra-alkylated compound) was less than 10% after incubation in buffer solution of pH 4.0 and in Milli-Q water at 50°C for 5 days. Therefore, test chemical is considered hydrolytically stable at pH 4.0 and in Milli-Q water. In buffer solutions pH 7.0 and pH 9.0, the relative difference between the substance concentrations measured after incubation at 50°C for 5 days and at t = 0 was more than 10% (+52% in buffer solution pH 7.0 and -37% in buffer solution pH 9.0). The percentage recovery of the test chemical after 5 days was determined to be 99.0, 82 and 107% at pH 4, 7 and 9, respectively. As no hydrolysis of test chemical was observed for a period of 5 days,the half-lives was determined to be > 5 days at pH 4, 7 and 9 & at a temperature of 50⁰C, respectively. Based on the half-life values, it is concluded that test chemical is not hydrolysable.

In an another hydrolysis study, the neutral hydrolysis half-life value of test chemical was determined to be ranges from 20-40 days, respectively. Based on the half-life values, it is concluded that test chemical is not hydrolysable.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the hydrolysis half-life value of the test chemical Butylstannonic acid can be expected to be range from  > 5 to 40 days, respectively. Thus, based on this, test chemical Butylstannonic acid is considered to be not hydrolysable in water.

Biodegradation in water

Predicted data for the target compoundButylstannonic acid(CAS No. 2273-43-0) and various supporting weight of evidence studies for its structurally and functionally similar read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction using the Estimation Programs Interface Suite (2017), the biodegradation potential of the test compoundButylstannonic acid(CAS No. 2273-43-0) 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 chemicalButylstannonic acidis expected to be not readily biodegradable.

 

In a supporting weight of evidence study from authoritative database (2017), the test chemical was subjected to biodegradation test by taking activated sludge as inoculums at 30 mg/L concentration. Biodegradation was analysed by using BOD and HPLC parameters. The initial concentration of test chemical taken was 100 mg/L. Percent biodegradation of test chemical was determined to be 0.0 % by BOD parameter and 1.0 % by HPLC parameter in 28 days. On the basis of percent degradation value it is concluded that test chemical is not readily biodegradable.

 

For the test chemical,biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of test substance. Activated sludge 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. The percentage degradation of test substance was determined to be 36 and 48% by BOD and GC parameter in 28 days. Thus, based on percentage degradation, test chemical is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical Butylstannonic acid (from modelling database, 2017), it can be concluded that the test substance Butylstannonic acid can be expected to be not readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (2017) prediction model was run to predict the half-life in water and sediment for the test compound Butylstannonic acid (CAS No. 2273 -43 -0). If released in to the environment, 26 % 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 15 days (360 hrs). The half-life (15 days estimated by EPI suite) indicates that the chemical is not persistent in water and the exposure risk to aquatic animals is low whereas the half-life period of test chemical Butylstannonic acid in sediment is estimated to be 135 days (3240 hrs). However as the percentage release of test chemical into sediment is less than 1 %(i.e., reported as 0.249) indicates that test chemical Butylstannonic acid is not persistent in sediment as well.

Biodegradation in soil

The half-life period of test chemicalButylstannonic acid(CAS No.2273 -43 -0) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (2017). If released into the environment, 72.3 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemicalButylstannonic acidin soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemicalButylstannonic acid, it is concluded that the chemical is not persistent in the soil environment and the exposure risk to soil dwelling animals is low.

On the basis of available information, the test substance Butylstannonic acid can be considered to be not readily biodegradable in nature.

Bioaccumulation : aquatic/sediments:

Predicted data study for target chemical Butylstannonic acid (CAS No.2273-43-0) and two experimental studies for its structurally similar read across chemical have been conducted and their results are summarized below.

The first weight of evidence was done by using BCFBAF Program (v3.00) model of Estimation Program Interface (EPI suite, 2017 ) and the estimated bio concentration factor (BCF) for Butylstannonic acid (CAS No.2273-43-0) is 100 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000.

Next weight of evidence study was done from authoritative database (2017) in this study the Bioaccumulation test was conducted for 8 weeks for determination the bioconcentration factor (BCF) of test chemical on test organism Cyprinus carpio. The vehicle used in the study was : HCO-20, HCO-60, Olive oil, Crys sugar, and Concentration of vehicle: 1st Concentration area: HCO-20 10000 ppm(w/v), HCO-60 10000 ppm(w/v), Olive oil 2500 ppm(w/v), Crystal sugar 5 ppm(w/v), 2nd Concentration area: HCO-20 1000 ppm(w/v), HCO-60 1000 ppm(w/v), Olive oil 250 ppm(w/v), Crystal sugar 500 ppm(w/v). The recovery ratio was in Test water at 1st concentration area : 100 %, 2nd concentration area : 101 %, Fish : 81.2 %, - Limit of detection : Test water : 1stconcentration area : 0.06 ppm, 2nd concentration area : 0.006 ppm, Fish : 0.3 ppm. Nominal concentrations used was 1st Concentration area: 0.5 mg/L (w/v), 2nd Concentration area: 0.05 mg/L (w/v) and Range finding study was carried out on Rice fish (Oryzias latipes) TLm(48h) 40 ppm(w/v). Thus according to static Fish test The bioconcentration factor (BCF) for test chemical was observed to be <= 0.7 - 18 L/kg at dose concentration 0.5 mg/L and <= 7.1 - 69 L/kg at dose concentration 0.05mg/L on test organism Cyprinus carpio during 8 weeks period. Therefore it is concluded that test chemical is non bioaccumulative.

Last weight of evidence study was done from authoritative database (2017) in this study the BCF value of test chemical estimated was 80 dimensionless by using log Kow of 3.39 and regression derived equation and it is far less than 2000 criteria so it is concluded that test chemical is non bioaccumulative.

On the basis of all the studies mentioned above it can be concluded that target chemical Butylstannonic acid (CAS No.2273-43-0) is non bioaccumulative in nature as all the BCF values are far less than 2000 criteria.

Adsorption / desorption

Predicted data for the target compoundButylstannonic acid(CAS No. 2273-43-0) and various supporting weight of evidence studies for its structurally and functionally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

The Soil Adsorption Coefficient i.e Koc value of test chemical Butylstannonic acid (CAS No:2273-43-0) was estimated using EPI suite KOCWIN Program (v2.00) as 201.6 L/kg (log Koc= 2.3045)  by means of MCI method at 25 deg.C.

 

In a supporting weight of evidence study from authoritative database (2017) for the test item,the Koc value for test chemical was estimated by using a structure estimation method based on molecular connectivity indices. The estimated Koc value was 72 dimensionless and log Koc 1.8573, respectively.

 

For the test chemical,adsorption study was conducted for estimating the adsorption coefficient (Koc) value of test chemical. The adsorption coefficient (Koc) value was calculated using as structure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance was estimated to be 80 (Log Koc = 1.903).

 

On the basis of above overall results for target chemicalButylstannonic acid(from modelling databases,2017), it can be concluded that the Koc value of test substance Butylstannonic acid was estimated to be 201.6 (Log Koc = 2.3045) indicating that the test chemical Butylstannonic acid has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.