Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Biodegradation in water

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the percentage degradation of the test chemical Castor oil, sulfated can be expected to be ranges from 64.2 to 99%, respectively in 30 days. Thus, based on this, test chemical Castor oil, sulfated is considered to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test compound Castor oil, sulfated (CAS No. 8002 -33 -3). If released in to the environment, 13.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Castor oil, sulfated 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 Castor oil, sulfated 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 0.0313%), indicates that Castor oil, sulfated is not persistent in sediment.

 

Biodegradation in soil

The half-life period of Castor oil, sulfated (CAS No. 8002 -33 -3) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment, 86.2% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Castor oil, sulfated in soil is estimated to be 120 days (2880 hrs). Based on this half-life value of Castor oil, sulfated, 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.

 

Additional information

Biodegradation in water

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the biodegradability of the test chemical Castor oil, sulfated. The studies are as mentioned below:

Biodegradation study was conducted for 30 days for evaluating the percentage biodegradability of test substance. The study was performed using the respirometry test under aerobic conditions at a temperature of 20⁰Cfor determining the biochemical oxygen demand (BOD) parameter of the test chemical. A master culture, developed in the laboratory under continuous flow conditions, was used as inoculums.For the preparation of master culture,a 6 l continuous flow coarse pore (20lm) membrane bioreactor was seeded with activated sludge from a local municipal wastewater treatment plant. The influent flow was 0.6 l per day, with canola oil as the sole carbon source (868 mg/l). The feed oil concentration, expressed in mg/l as free fatty acid, was 50.6 (16:0), 20.7 (C18:0), 559.0 (C18:1), 188.9 (C18:2), and 49.1 (C18:3). The residual concentrations of these fatty acids observed in the mixed liquor were 30.7 (16:0), 18.29 (C18:0), 353.1 (C18:1), 113.0 (C18:2), and 21.7 (C18:3) mg/l. Finally, trace levels of four FAs (µg/l) were found in the effluent 3.5 (16:0), 1.9 (C18:0), 8.3 (C18:1), and 2.2 (C18:2). The solids were separated, washed with a sterile saline solution, and collected for subsequent freezing. The frozen culture was stored, at-80⁰C in glycerol in sealed vials (4.5 ml) for use throughout the study. Respirometry tests were run in three computerized respirometers, Comput-Ox WB Series (N-Con Systems, Crawford, GA, USA) with a total capacity of 36 flasks (500 ml). Each flask was equipped with a trap containing 0.1 N potassium hydroxide to remove the evolved carbon dioxide from the system. The amount of CO2 produced within the system was calculated at discrete points based on the relative decrease in pH of the KOH solution, as indicated by the pH indicator dye Alizarin Red. For each test, 24 vials were taken out and allowed to reach room temperature (21⁰C). Then, the content of the vials were transferred to a 500 flask. A volume (200 ml) of saline solution (0.85% NaCl) was added in order to dilute the glycerol. After that, the biomass was centrifuged and the supernatant removed. The biomass was reconstituted with 108 ml of the saline solution. 250 ml SuperQ water, with the appropriate mineral components (buffer [KH2PO4, 5 mg/ml] and nutrients was used as the medium for the degradation of test chemical.Vitamins such as4-Aminobenzoic acid, Biotin, Cyanocabalamin (B12), Folic acid dehydrate (99%), Nicotinic acid (98%), Panthotenic acid, Ca salt hydrate, Pyridoxine, hydrochloride (98%), (-)-Riboflavin (98%) Thiamine hydrochloride and Thioctic acid (98%) were used as an additional substrate for the study. For controls, three blank flasks with mineral solution and TAG only and three additional flasks with mineral solution and inoculums only were run at the same time. The sampling events were distributed as follows: for verifying initial TAG concentration, triplicate sample flasks were sacrificed at time zero, corresponding to the actual starting point of the respirometry experiment and after the flask preparation and equilibration times were completed (3 h). At each one, three sample flasks, randomly selected, were sacrificed by lowering the pH of the water to 2 with concentrated hydrochloric acid. After biomass deactivation, flasks were analyzed for their chemical composition and toxicity. The content of the respirometry flasks was a complex aqueous solution or mixture of soluble compounds, colloids, and suspended solids. Vacuum filtration was used to separate the insoluble components (solid phase) from the water (liquid phase). The apparatus consisted of a 150 ml fritted glass funnel (Corning, Acton, MA, USA) with a glass fiber filter (0.45lm) on top of the fritted disk as a support for a 5 cm bed of silanized glass beads. After filtration, the liquid phase (pH approx 2) was analyzed for free fatty acids (FFAs) and degradation by-products. After a subsample was collected for toxicity determination, FFAs and other by-products were separated from water by means of solid-phase extraction (SPE). The stationary phase (500 mg) was octyl C8 (Envi-8, Supelco). Cartridges were conditioned by passing 10 ml of 40% acetone in dichloromethane (DCM) followed by 10 ml of methanol and, finally, 10 ml superQ water (pHapprox2.0). All samples, blanks, controls, and SPE extraction banks were spiked with a surrogate compound, undecanoic acid (Sigma–Aldrich), for recovery control, and then loaded at a rate of 6 ml/min. After a drying period of 20 min, analytes were eluted with 10 ml of acetone/DCM (40:60). Finally, the extracts were transferred to reaction vials and evaporated to dryness under a gentle stream of nitrogen as a preliminary step before analysis by GC/MS of the free fatty acid methyl esters (FAMEs). Triacylglycerols and fatty acids were determined by reversed-phase HPLC on an 1100 Series Chromatographic System with a diode array detector (Agilent Technologies, CA, USA). Two methods, were used. In both protocols, a C8 column (200·2.1 mm Hypersil MOS, 5lm) was required. For TAGs, the composition of the mobile phase was water (A) and acetonitrile/methyl-t-butyl-ether (9:1) (B). A solvent gradient was used: at 0 min 87% B; at 25 min 100% B. These analytes were detected at 215 nm. This method also allowed the separation of hydroperoxides detectable qualitatively at 240 nm. However, as a final step prior to injection, FAs were derivatizated with bromophenacyl bromide, obtaining their corresponding esters (FABPBEs). In this case, a mix of water (A) and acetonirile + 1% tetrahydrofuran (B) was used as mobile phase, being the solvent gradient: at 0 min 30% B; at 15 min 70% B; at 25 min 98% B. The detection wavelength for the fatty acids was 258 nm. The oxygen uptake by each flask was continuously monitored and recorded hourly by the computer system. Experimental values for test chemical were fit to the BOD equation, using SigmaPlot 10 (Systat Software, Inc., CA, USA). The coefficients of determination (R2) were very close to one, standard errors were two orders of magnitude smaller than the estimated values, and their respective 95% confidence intervals showed narrow width.The percentage degradation and the first order rate coefficient of test chemical was determined to be 77.2% by O2 consumption parameter in 30 days and 0.0025 /h, respectively. Thus, based on percentage degradation, test chemical is considered to be readily biodegradable in nature.

Biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of another test chemical. The study was performed under aerobic conditions.The percentage degradation of test chemical was determined to be 64% by using test material analysis as a parameter in 28 days. Thus, based on percentage degradation, test item is considered to be readily biodegradable in nature.

Another ready biodegradability study of additional test chemical was assessed by OECD 301B guideline also known as Sturm test. Installations and equipment used in the test were as described in the OECD Guideline 301B. The size of the carbosys was reduced from 5 l to 3l and the volume of the solution from 2 to 1.5 l. A magnetic stirrer with a PTFE – coated rod of 6 cm length rotating at approximately 60 rpm was used for agitation. A constant temperature of 23°C was maintained by immersion of carbosys in a water bath. Sludge for the preparation of the inoculum was taken from a sewage treatment plant receiving predominantly domestic waste. The inoculum and the mineral solutions were prepared according to the OECD 301 guidelines. In the method with direct dispersion of the test chemical (20mg/l) was added as a powder or as a suspension in water prepared by ultrasonic dispersion, to the carbosys containing the inoculum. No additional treatment was given to the mixture containing the inoculum. In the method with solid carriers the samples were prepared by melting calcium stearate on glass filter papers. The glass filter papers were cut into small pieces before putting them into carbosys. The test chemical was biodegraded under all test conditions, fulfilling the strict criteria of ready biodegradability [60% within 10 days] except in one case where it was applied on a glass filter in a non-agitated container. The solubility of 2mg/l water was apparently sufficient to ensure the continuous availability of the test chemical to the bacteria. The decreased rate of biodegradation of the sample melted on the glass filter can be explained by a reduction in the availability of calcium stearate as a consequence of the melting operation [glazing of the surface] and the absence of agitation. The percentage degradation of test substance was determined to be 91% degradation by CO2 evolution parameterin 24 days in absence of agitation and glass filter paper was not used as a carried, whereas 99% degradation was observed by CO2 evolution parameter in 24 days in absence of agitation and 55 and 88% degradation was observed by CO2 evolution parameter in 24 days when glass filter papers was used as a carrier.In addition to this,test substance also undergoe degradation upto 72% and 84% in 20 days by CO2 evolution parameter using glass filter papers and ultrasound as a carrier and in presence of agitation.Thus, based percentage degradation, test chemical was considered to be readily biodegradable in water.

On the basis of the experimental studies of the structurally and functionally similar read across chemical and applying the weight of evidence approach, the percentage degradation of the test chemical Castor oil, sulfated can be expected to be ranges from 64.2 to 99%, respectively in 30 days. Thus, based on this, test chemical Castor oil, sulfated is considered to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test compound Castor oil, sulfated (CAS No. 8002 -33 -3). If released in to the environment, 13.8% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of Castor oil, sulfated 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 Castor oil, sulfated 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 0.0313%), indicates that Castor oil, sulfated is not persistent in sediment.

 

Biodegradation in soil

The half-life period of Castor oil, sulfated (CAS No. 8002 -33 -3) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database. If released into the environment, 86.2% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of Castor oil, sulfated in soil is estimated to be 120 days (2880 hrs). Based on this half-life value of Castor oil, sulfated, 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 Castor oil, sulfated can be considered to be readily biodegradable in nature.