2-(hydroxymethylamino)ethanol

Endpoint summary

Description of key information

Hydrolysis

Aqueous hydrolysis of test chemical 2-(hydroxymethylamino)ethanol (CAS no. 34375 -28 -5) was carried out for 30 days at pH 5, 7 and 9, respectively (HPV Chemical Challenge Program, 2016). Since radioactively labeled material was not available for the study, the 95% grade compound was used and chemical analysis was used to identify the breakdown products. The initial amount of test material dissolved in the buffers was 250 µg/ml. The buffers were autoclaved after preparation and before the test substance was added. Efforts were made to maintain sterility. For the duration of the study, the solutions were maintained in darkness in a water bath adjusted to 25°C. The temperature of the bath was recorded once daily, with an average of 25°C, ranging from 24.9 to 25.1°C. The solutions were sampled for immediate chromatographic analysis at intervals of 0, 1, 3, 7, 14, 21 and 30 days. Samples from each time point were also placed in the freezer for further analysis. Liquid chromatographic analysis of the fresh samples using post-column detection allowed quantitation of primary amines. There was immediate, or nearly immediate hydrolysis of Troysan at pH 5.0, 7.0 and 9.0 at 25°C. The hydrolysis of Troysan 174 to formaldehyde and ethanolamine was too rapid to be quantified. The recovery of 2 degradation substances together after 30 days (calculated as a percentage of the initial, using Troysan 174 dissolved in water as the standard) averaged 91.5% at pH 5, 97.5% at pH 7 and 97.1% at pH 9, respectively. Formaldehyde and ethanolamine was the breakdown product of the test chemical 2 -(hydroxymethylamino)ethanol.

Biodegradation in water

Biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of test substance 2 -[hydroxy(methyl)amino]ethanol (CAS no. 34375-28-5) (EnviChem, 2014). 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 determined to be 68% degradation by BOD parameter in 14 days. Thus, based on percentage degradation, test substance 2 -[hydroxy(methyl)amino]ethanol was considered to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound

2-[hydroxy(methyl)amino]ethanol (CAS No. 34375 -28 -5). If released in to the environment, 33.9% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-[hydroxy(methyl)amino]ethanol in water is estimated to be 8.66 days (208 hrs). The half-life (8.66 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 whereas the half-life period of 2 -[hydroxy(methyl)amino]ethanol in sediment is estimated to be 77.916 days (1870 hrs). Based on this half-life value, it indicates that 2 -[hydroxy (methyl)amino]ethanol is not persistent in sediment.

Biodegradation in soil

The half-life period of 2-[hydroxy(methyl)amino]ethanol (CAS No. 34375 -28 -5) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 66.1% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2 -[hydroxy(methyl)amino]ethanol in soil is estimated to be 17.33 days (416 hrs). Based on this half-life value of 2-[hydroxy (methyl) amino]ethanol, it is concluded that the chemical is not persistentin the soil environment and the exposure risk to soil dwelling animals is moderate to low.

Bioaccumulation: aquatic / sediment

From Scifinder,Chemspider database and Using Bio-concentration Factor (v12.1.0.50374) module of ACD lab to determine Bio-concentration Factor over the entire pH scale 1-14 of the test substance 2-[hydroxy(methyl)amino]ethanol estimated to be 1 (dimentionless).This value indicates that the test substance2-[hydroxy(methyl)amino]ethanolfound to be non-accumulative in aquatic organisms.

Adsorption / desorption

The Soil Adsorption Coefficient i.e Koc value of 2-[hydroxy(methyl)amino]ethanol was estimated using EPI suite  KOCWIN (v2.00) program as Koc 1 L/kg(log Koc=0)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance 2-[hydroxy(methyl)amino]ethanol  has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Additional information

Hydrolysis

Aqueous hydrolysis of test chemical 2-(hydroxymethylamino)ethanol (CAS no. 34375 -28 -5) was carried out for 30 days at pH 5, 7 and 9, respectively (HPV Chemical Challenge Program, 2016). Since radioactively labeled material was not available for the study, the 95% grade compound was used and chemical analysis was used to identify the breakdown products. The initial amount of test material dissolved in the buffers was 250 µg/ml. The buffers were autoclaved after preparation and before the test substance was added. Efforts were made to maintain sterility. For the duration of the study, the solutions were maintained in darkness in a water bath adjusted to 25°C. The temperature of the bath was recorded once daily, with an average of 25°C, ranging from 24.9 to 25.1°C. The solutions were sampled for immediate chromatographic analysis at intervals of 0, 1, 3, 7, 14, 21 and 30 days. Samples from each time point were also placed in the freezer for further analysis. Liquid chromatographic analysis of the fresh samples using post-column detection allowed quantitation of primary amines. There was immediate, or nearly immediate hydrolysis of Troysan at pH 5.0, 7.0 and 9.0 at 25°C. The hydrolysis of Troysan 174 to formaldehyde and ethanolamine was too rapid to be quantified. The recovery of 2 degradation substances together after 30 days (calculated as a percentage of the initial, using Troysan 174 dissolved in water as the standard) averaged 91.5% at pH 5, 97.5% at pH 7 and 97.1% at pH 9, respectively. Formaldehyde and ethanolamine was the breakdown product of the test chemical 2 -(hydroxymethylamino)ethanol.

Biodegradation in water

Various experimental and predicted data for the target compound 2 -[hydroxy(methyl)amino]ethanol (CAS No. 34375 -28 -5) and various supporting weight of evidence studies for its read across substances were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental study from secondary source (EnviChem, 2014), biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of test substance 2 -[hydroxy(methyl)amino]ethanol (CAS no. 34375-28-5). 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 determined to be 68% degradation by BOD parameter in 14 days. Thus, based on percentage degradation, test substance 2 -[hydroxy(methyl)amino]ethanol was considered to be readily biodegradable in nature.

 

In a prediction using the Estimation Programs Interface Suite (EPI suite, 2017), the biodegradation potential of the test compound 2-[hydroxy(methyl)amino]ethanol(CAS No. 34375-28-5) 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 2 -[hydroxy(methyl) amino]ethanol is expected to be readily biodegradable.

 

In a supporting weight of evidence study from authoritative database and secondary source (J-CHECK and OECD SIDS) for the read across chemical 1,4 -Butanediol (CAS no. 110 -63 -4),biodegradation study was conducted for 14 days for evaluating the percentage biodegradability of read across substance 1,4 -Butanediol. The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I)). 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 was determined to be 83, 94 and 100% by BOD, TOC removal and GC parameter in 14 days. Thus, based on percentage degradation,1,4-Butanediol is considered to be readily biodegradable in nature.

 

For the read chemical hexane (CAS no. 110-54-3) from authoritative database (HSDB, 2016),biodegradation experiment was conducted for evaluating the percentage biodegradability of read across substance hexane (CAS no. 110-54-3) under aerobic conditions. Activated sludge was used as a test inoculum for the study. The percentage degradation of read across substance was determined to be 100% in less than 30 days. Thus, based on percentage degradation, hexane is considered to be readily biodegradable in nature.

 

Another biodegradation study was conducted for evaluating the percentage biodegradability of read across substance heptane (CAS no. 142-82-5) under aerobic conditions (from peer reviewed journal F. Solano-Serena et. al, 1999 and authoritative database HSDB, 2016). Activated sludge was used as a test inoculum obtained from urban waste water treatment plant. A microbial suspension containing 3 g/l dry weight was obtained by centrifugation of the sludge at 15000 g for 20 mins and resuspension of the centrifuged biomass in the same volume of nutrient solution. Inoculum conc. of 100 mg/l was used. The centrifuged biomass could be used immediately or stored at -80°C for several months without significant loss of degradation capacity. The vitamin – supplemented mineral salt medium was used as a nutrient solution. Individual hydrocarbons were added to the nutrient solution as sole carbon source. 500 ml flasks closed with Teflon-coated stoppers and with side-arms equipped with Mininert valves was used as a culture apparatus for the study. Test substance was added to 50 ml of inoculated culture medium through a valve with a Hamilton syringe. After an incubation period of 25 days at 30°C with an alternative shaking (70 strokes /min), 5 ml of CH2Cl2, containing 600 mg/ml dodecane as internal standard, was introduced into the flask through the valve and the remaining hydrocarbon were extracted for 1 h under shaking. The flasks were refrigerated overnight at 4°C before opening and the suspensions were centrifuged at 35000 g for 30 min at 4°C. The CH2Cl2 phase of each flask was then analyzed by gas chromatography. Abiotic controls containing 1 g/l HgCl2 were run under the similar test conditions. Carbon dioxide was measured with a chromatograph equipped with a thermal conductivity detector and a Porapak Q column (80/100 mesh, 2 m) using an external standard method. The carried gas was helium and the column temperature was 50°C. The temperature of the injector and that of the detector was 100°C. Samples (250µl) of the headspace gas of culture flasks were withdrawn with a gas-tight syringe and injected into the chromatograph for CO2 determination. The kinetics of O2 consumption during gasoline degradation were determined in duplicate at 30°C over 25 d with the electrolytic respirometric equipment D-12 Sapromat. The percentage degradation of read across substance was determined to be 17 and 100% by O2 consumption, CO2 production and GC parameter after 2 and 25 days, respectively. Thus, based on percentage degradation, heptane is considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical 2-[hydroxy(methyl)amino]ethanol (from EnviChem, 2014 and EPI suite, 2017) and for its read across substance (from authoritative database J-CHECK, HSDB, peer reviewed journal and secondary source OECD SIDS), it can be concluded that the test substance 2 -[hydroxy(methyl)amino]ethanol can be expected to be readily biodegradable in nature.

Biodegradation in water and sediment

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound

2-[hydroxy(methyl)amino]ethanol (CAS No. 34375 -28 -5). If released in to the environment, 33.9% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2-[hydroxy(methyl)amino]ethanol in water is estimated to be 8.66 days (208 hrs). The half-life (8.66 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 whereas the half-life period of 2 -[hydroxy(methyl)amino]ethanol in sediment is estimated to be 77.916 days (1870 hrs). Based on this half-life value, it indicates that 2 -[hydroxy (methyl)amino]ethanol is not persistent in sediment.

Biodegradation in soil

The half-life period of 2-[hydroxy(methyl)amino]ethanol (CAS No. 34375 -28 -5) in soil was estimated using Level III Fugacity Model by EPI Suite version 4.1 estimation database (EPI suite, 2017). If released into the environment, 66.1% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2 -[hydroxy(methyl)amino]ethanol in soil is estimated to be 17.33 days (416 hrs). Based on this half-life value of 2-[hydroxy (methyl) amino]ethanol, it is concluded that the chemical is not persistentin the soil environment and the exposure risk to soil dwelling animals is moderate to low.

On the basis of available information, the test substance 2 -[hydroxy(methyl)amino]ethanol can be considered to be readily biodegradable in nature.

Bioaccumulation: aquatic / sediment

Three results including different predicted data from validated models for bioaccumulation (BCF) endpoint of target chemical 2-[hydroxy(methyl)amino]ethanol (Cas no. 34375-28-5) were summarized as follows:

 

First prediction done using ACD (Advanced Chemistry Development)/I-Lab; Algorithm Version: v5.0.0.184 using Bio-concentration Factor (v12.1.0.50374) module and also from Scifinder and chemspider database; 2017 indicate the bio-concentration Factor over the entire pH scale 1-14 of the test substance 2-[hydroxy(methyl)amino]ethanol estimated to be 1 (dimentionless).This value indicates that the test substance 2-[hydroxy(methyl)amino]ethanol found to be non-accumulative in aquatic organisms.

Another validated prediction by BCFBAF (v3.00) model and PBT profiler database indicate the estimated bio concentration factor (BCF) for 2-[hydroxy(methyl)amino]ethanol is 3.2 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000. Thus it is concluded that 2-[hydroxy(methyl)amino]ethanol is not expected to bio accumulate in the aquatic environment.

Above all predictions assist by result from CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical) indicate  the bioaccumulation i.e BCF for test substance 2-[hydroxy(methyl)amino]ethanol was estimated to be 3.14 dimensionless . The predicted BCF result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance 2-[hydroxy(methyl)amino]ethanol non-bioaccumulative in nature as it does not exceed the BCF criteria of 2000.

Thus based on the above information for bioaccumulation endpoint, it can be concluded that the test substance 2-[hydroxy(methyl)amino]ethanol (Cas no. 34375-28-5) is expected to be non Bioaccumulative in aquatic environment as none of the study indicate the 2-[hydroxy(methyl)amino]ethanol exceed the BCF threshold of 2000.

Adsorption / desorption

Five results including different predicted data from validated models for adsorption (KOC) endpoint of target chemical 2-[hydroxy(methyl)amino]ethanol (Cas no. 34375-28-5) were summarized as follows:

 

First study from prediction by KOCWIN model (v2.00) of EPI suite which indicate the adsorption value of 2-[hydroxy(methyl)amino]ethanol was estimated as 1 L/kg(log Koc=0) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 2-[hydroxy(methyl)amino]ethanol has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

 

Above result is assist by ACD (Advanced Chemistry Development)/I-Lab; Algorithm Version: v5.0.0.184 using Adsorption Coefficient module (v12.1.0.50374) module; 2017 indicate the Koc value of test substance 2-[hydroxy(methyl)amino]ethanol was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 1 to 2.57 ( log Koc of max.value = 0.40) at pH range 1-14.. This Koc value indicates that the test substance has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Result From CompTox Chemistry Dashboard using OPERA (OPEn (quantitative) structure-activity Relationship Application)  V1.02 model in which calculation based on PaDEL descriptors (calculate molecular descriptors and fingerprints of chemical) indicate the adsorption coefficient i.e KOC for test substance 2-[hydroxy(methyl)amino]ethanol was estimated to be 11.7 L/Kg.The predicted KOC result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance 2-[hydroxy(methyl)amino]ethanol has high mobility in soil compartment.

And Scifinder database suggest the soil adsorption coefficient i.e Koc value of test substance 2-[hydroxy(methyl)amino]ethanol  was estimated to be 1-2.52 (Log koc of max. value -0.40) at pH range 1-10 at temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 2-[hydroxy(methyl)amino]ethanol has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Last study from Chemspider - ACD/PhysChem Suite indicate the soil adsorption coefficient i.e Koc value of test substance 2-[hydroxy(methyl)amino]ethanol was estimated to be 1 (log koc: 0) at pH 5.5 and 1.76 (log koc: 0.24) at pH 7.4 and temp.25 deg.C. This Koc value at different pH indicates that the substance 2-[hydroxy(methyl)amino]ethanol has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Thus all available studies for adsorption endpoint come to conclusion that the test substance 2-[hydroxy(methyl)amino]ethanol (Cas no. 34375-28-5) is expected to have high mobility in soil and sediment compartment.