4,4'-methylenedi-2,6-xylenol

Endpoint summary

Description of key information

Stability:

Hydrolysis:

On the basis of the results of both the studies and applying the weight of evidence approach, it can be concluded that the test chemical is not hydrolysable.

Biodegradation:

Biodegradation in water:

Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test chemical 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 is expected to be not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 5.86  % 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 lowwhereas the half-life period of test chemical in sediment is estimated to be  337.5 days ( 8100 hrs). 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 (EPI suite, 2018). If released into the environment, 61.8 % 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 low .

Bioaccumulation:

Bioaccumulation: aquatic/sediments:

Using BCFBAF Program (v3.00) model of EPI suite (2018) the estimated bio concentration factor (BCF) for  is 1340 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is nonbioaccumulative in food chain.

Transport and distribution:

Adsorption/desorption:

The Soil Adsorption Coefficient i.e. Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 108600 L/kg (log Koc= 5.0357) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical  has very strong sorption to soil and therefore test chemical has negligible  migration potential to ground water.

Additional information

Stability:

Hydrolysis:

Two studies have been reviewed to determine the hydrolysis reaction of the test chemical. The studies are as mentioned below:

In first study it was mentioned that the compounds containing carbon, hydrogen, and oxygen, esters and epoxides are susceptible to hydrolysis under the OECD test conditions (OECD Guideline 111). For these hydrolysis reactions to occur, there must be 1) an electrophylic carbon atom which is 'attacked' by oxygen; and 2) a 'leaving group' which departs from the attacked carbon atom. The hydrolysis reaction of test chemical would occur by attack of water or OH- at C1, because this is the most electropositive carbon in this molecule due to the electron withdrawing effect of the phenolic OH group and the product of this reaction would be test chemical itself, indicating that there would be no net hydrolysis.

Therefore, test chemical would be hydrolytically stable under the conditions of the OECD test (OECD Guideline 111)

Another study was reviewed fom authoritative database (HSDB) in this the test chemical is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups which menas it is stable and not hydrolysable.

On the basis of the results of both the studies mentioned above and applying the weight of evidence approach, it can be concluded that the test chemical is not hydrolysable.

Biodegradation:

Biodegradation in water:

Different studies have been reviewed for biodegradation in water endpoint for test chemical and its read across chemicals and their results are summarized below.

In first study the Estimation Programs Interface Suite (EPI suite, 2018) was run to predict the biodegradation potential of the test chemical 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 is expected to be not readily biodegradable.

Next study was experimental study reviewed from authoritative database( J check) in this study the Biodegradation experiment was carried out of test chemical by taking activated sludge as inoculums at 30 mg/L concentration for 28 days. Biodegradation was analyzed by using two parameters that are BOD and test material analysis by HPLC .The initial concentration of test chemical was 100 mg/L. After 4 weeks of incubation percent biodegradation of test chemical was observed to be 7.0 % by BOD (O2 consumption) parameter, 0.0 by TOC removal parameter and 0.0 % by test material analysis by HPLC in 28 days. On the basis of percent degradation value it is concluded that test chemical is not readily biodegradable.

Last was also experimental study reviewed from j check in this study the Biodegradation experiment was performed for test chemical by taking activated sludge as inoculums at 30 mg/L concentration for 28 days. Biodegradation was analyzed by using two parameters that are BOD and test material analysis by HPLC .The initial concentration of test chemical was 100 mg/L. After 4 weeks of incubation Percent biodegradation of test chemical was observed to be 2.0 % by BOD (O2 consumption) parameter and 1.0 % by test material analysis by HPLC parameter in 28 days. On the basis of percent degradation value it is concluded that test chemical is not readily biodegradable.

By considering results of all the studies mentioned above it is concluded that test chemical is not readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2018) prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 5.86  % 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 lowwhereas the half-life period of test chemical in sediment is estimated to be  337.5 days ( 8100 hrs). 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 (EPI suite, 2018). If released into the environment, 61.8 % 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 low.

Bioaccumulation:

Bioaccumulation: aquatic/sediments:

Different studies have been reviewed for Bioaccumulation in aquatic organisms endpoint for test chemical and its read across chemicals and their results are summarized below.

The first study was done by using BCFBAF Program (v3.00) model of EPI suite (2018) in this study the bio concentration factor (BCF) for  estimated was 1340 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical is non-bioaccumulative in food chain.

In another study using Bio-concentration Factor (v12.1.0.50374) module the Bio-concentration Factor at range pH 0-6, 7, 8, 9 and 10  of the test chemical was estimated to be 1765 , 1764, 1754, 1662, and 1039 dimensionless respectively and in range 1-113 dimensionless at pH range 11-14.These values indicate that the chemical is non-bioaccumulative in aquatic organisms as this value does not exceed 2000 criteria.

Third study was experimental study reviewed from authoritative database (J check) in this study the Bioaccumulation test was conducted for 6 weeks for determination the bioconcentration factor (BCF) of chemical on test organism Cyprinus carpio. Nominal concentrations 1st Concentration area: 0.2 ppm(w/v), 2nd Concentration area: 0.02 ppm(w/v) and range-finding / preliminary study wa Test concentrations : TLm(48h) 14.3 ppm(w/v), Rice fish (Oryzias latipes) and test system used was vessels for volatile substances. The vehicle used in this study was Tween 80, and its concentration was 1st Concentration area: 2 ppm(w/v), 2nd Concentration area: 0.2 ppm(w/v). Recovery ratio :Test water : 1st concentration area : 91.8 %, 2nd concentration area : 84.5 %, Fish : 94.0 %, - Limit of detection : Test water 1st concentration area : 17 ppb, 2nd concentration area : 1.9 ppb, Fish : 0.06 ppm. Thus according to static Fish Test The bioconcentration factor (BCF) for chemical was determined according static fish test. The BCF value was observed to be in range 6.5-10 L/kg at dose concentration 0.2 mg/L and 2.7-8.1 L/kg at dose concentration 0.02 mg/L on test organism Cyprinus carpio during 6 weeks period. Therefore it is concluded that this test chemical is non-bioaccumulative. These BCF values indicate that the test substance is not bioaccumulative in fish and food chain as these values are far less than 2000 criteria.

Last study was reviewed from authoritative database (HSDB) in this study the BCF value of test chemical estimated was 37 dimensionless by using log Kow of 2.36 and regression derived equation and it is far less than 2000 criteria. On the basis of calculated BCF value it is concluded that chemical is non bioaccumulative.

By considering results of all the studies mentioned above it is concluded that test chemical is not bioaccumulative in fish and food chain all BCF values are far less than 2000 criteria of CLP regulation.

Transport and distribution:

Adsorption/desorption:

Different studies have been reviewed for Adsorption endpoint for test chemical and its read across chemical and their results are summarized below.

In first study the Soil Adsorption Coefficient i.e. Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 108600 L/kg (log Koc= 5.0357) by means of MCI method at 25 deg. C

In another study the Soil Adsorption Coefficient i.e Koc value of test substance was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 7334 dimensionless (log Koc= 3.9) at pH 7.

Last study was reviewed from authoritative database in this study the Koc value for test chemical estimated was 19000 dimensionless and log Koc is 4.9590.

By considering results of all the studies mentioned above it is concluded that log Koc value of test chemical can be in range 3.9- 5.03 this range log Koc value suggests that test chemical test chemical is expected to have very strong sorption to soil and sediment and therefore has negligible migration potential to ground water.