2,3,5-trimethylphenol

Endpoint summary

Description of key information

Biodegradation in water

Preliminary screening of biodegradation of test chemical was carried out for 20 days for evaluating the percentage biodegradability of test substance 2,3,5 -trimethylphenol (PC. Singer et. al; 1978). Domestic sewage was used as a test inoculum obtained from Chapel Hill sewage treatment plant. Concentration of inoculum i.e, sludge used was 1.5 mg/l and initial test substance conc. used in the study was 5 mg/l, respectively. Test chemical was added to duplicate, acid washed, 300 ml BOD bottles. Dilution water was prepared from water which had been passed through activated carbon and ion exchange columns and then glass-distilled. Standard nutrients were added to the water as was 0.5 mg/l allythiourea for control of nitrification. The dilution water was seeded with 1.5 mg/l of domestic sewage. The BOD bottles were filled, stoppered and incubated in the dark at 18.33°C (65°F) for 20 days. O2 consumption was measured at various intervals over the 20 day period by means of a Weston and Stack dissolved oxygen meter. The percentage degradation of test substance was determined to be 80% by O2 consumption parameter in 20 days. Thus, based on percentage degradation, 2,3,5 -trimethylphenol is considered to be readily biodegradable in nature.

Biodegradation in water and sediemnt

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2,3,5 -trimethylphenol (CAS No. 697 -82 -5). If released in to the environment, 18.6% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2,3,5-trimethylphenol 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 whereas the half-life period of 2,3,5-trimethylphenol in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical 2,3,5-trimethylphenol into the sediment is less than 1% (i.e, reported as 0.828%), indicating that the chemical 2,3,5-trimethylphenolis not persistent in sediment.

Biodegradation in soil

The half-life period of 2,3,5-trimethylphenol (CAS No. 697 -82 -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, 80.5% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2,3,5-trimethylphenol in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 2,3,5-trimethylphenol, 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.

Bioaccumulation: aquatic / sediment:

From BCFBAF Program (v3.00) model of EPI suite the estimated bio concentration factor (BCF) for 2,3,5-trimethylphenol is 56.04 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.Thus it is concluded that 2,3,5-trimethylphenol is not expected to bio accumulate in fish and in the food chain.

Adsorption / desorption:

The Soil Adsorption Coefficient i.e Koc value of 2,3,5-trimethylphenol was estimated using EPI suite  KOCWIN Program (v2.00) as Koc 805.2 L/kg (log Koc = 2.905)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance 2,3,5-trimethylphenol has a Moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

Additional information

Biodegradation in water

Various experimental key study and supporting data for the target compound 2,3,5-trimethylphenol (CAS no. 697-82-5) were reviewed for the biodegradation end point which are summarized as below:

 

In an experimental key study, preliminary screening of biodegradation of test chemical was carried out for 20 days for evaluating the percentage biodegradability of test substance 2,3,5 –trimethylphenol (CAS no. 697-82-5) (PC. Singer et. al; 1978). Domestic sewage was used as a test inoculum obtained from Chapel Hill sewage treatment plant. Concentration of inoculum i.e, sludge used was 1.5 mg/l and initial test substance conc. used in the study was 5 mg/l, respectively. Test chemical was added to duplicate, acid washed, 300 ml BOD bottles. Dilution water was prepared from water which had been passed through activated carbon and ion exchange columns and then glass-distilled. Standard nutrients were added to the water as was 0.5 mg/l allythiourea for control of nitrification. The dilution water was seeded with 1.5 mg/l of domestic sewage. The BOD bottles were filled, stoppered and incubated in the dark at 18.33°C (65°F) for 20 days. O2 consumption was measured at various intervals over the 20 day period by means of a Weston and Stack dissolved oxygen meter. The percentage degradation of test substance was determined to be 80% by O2 consumption parameter in 20 days. Thus, based on percentage degradation, 2,3,5 -trimethylphenol is considered to be readily biodegradable in nature.

 

Another study of biodegradation was carried out for 14 days for evaluating the percentage biodegradability of test substance 2,3,5-trimethylphenol (CAS no. 697-82-5) (JAMES G. MUELLER et. al; 1991). Micro-organism was used as a test inoculum isolated from surface soil which was freshly obtained from theAmerican Creosote Works site. Microbial inoculum was prepared by mixing 25 g of creosote-contaminated surface soil (17) freshly obtained from the American Creosote Works site with 100 ml of 2.5 mM phosphate buffer (pH 7). After being mixed well, the suspension was centrifuged (2,500 rpm, 10 min) to remove larger soil particles. The resultant supernatant was decanted and used as a source of indigenous, "creosote-adapted" microorganisms for the ground water medium (GWM).Ground water medium (GWM) was used for the study.For the biodegradation study, approximately 400 liters of groundwater contaminated with creosote and PCP was recovered from an on-site sampling well. Groundwater was removed from a depth of 7 m through Teflon-coated Bev-a-line tubing (15 mm inner diameter) by means of an electric pump. Groundwater was delivered directly into two freshly rinsed, 208-liter steel drums (DOT-17E) and stored on site for ancillary testing. Five subsamples (1.0 liter) were collected in clean, sterile, 1.0-liter Wheaton bottles fitted with Teflon-lined screw caps and stored on ice for transport to the laboratory. Upon arrival at the laboratory, subsamples were stored in darkness at 2°C for subsequent biodegradation studies, toxicity and teratogenicity testing, and chemical analyses.

It contains2.5 ml of filtered groundwater (passed through a plug of silanized glass wool to remove undissolved solids) plus 12.5 ml of modified Bushnell-Haas medium.Additionally, two clean, sterile, 1.0-liter Wheaton bottles fitted with Teflon-lined screw caps received 200 ml of the same medium.Ground water contains the test chemical2,3,5-trimethylphenol. Wheaton bottles consist of 200 ml of ground water medium (which contain ground water and modified Bushnell-Haas medium. Duplicate 25 ml samples wereimmediately extracted for time zero analysis. Flasks were incubated at 30°C with shaking (200 rpm) in the dark for 14 days. Killed-cell controls were prepared for each sampling time point by adding 2.5 ml of a 37% formaldehyde solution to five of the shake flasks containing 25 ml of GWM. After 1, 3, 5, 8, and 14 days of incubation, the entire contents of two active flasks and one killed-cell control flask were separately extracted and analyzed by GC for the presence of creosote constituents. These data were compared with those obtained from untreated (non-inoculated) GWM that had been stored at 2°C during the 14-day incubation period.As the limit of detection of test chemical by GC is very low during a period 14 days, test chemical2,3,5-trimethylphenol can be considered to be readily biodegradable in nature. 

 

In a supporting study from peer reviewed journal (HIDESHI YANASE et. al; 1992), biodegradation experimented was conducted for 30 mins for evaluating the percentage biodegradability of test substance 2,3,5 –trimethylphenol (697-82-5). Phenol degrading bacteria (Agrobacterium spp.) was used as a test organism isolated from brine that had just emerged from a natural gas well under the sea near Niigata Prefecture, Japan. The identification of bacteria was carried out by the National Collection of Industrial and Marine Bacteria, Ltd., Scotland. Bacterial cells suspended in sterile artificial seawater containing 10% (vol/vol) glycerol were stored frozen at -80°C in plastic vials. Under the storage conditions, the isolates were viable and did not lose phenol degradation activity for at least 2 years. The reaction mixture contained 100 mM MOPS buffer (pH 7.0), 0.1 mM (13.61 mg/l) phenolic compound, and 4.5 mg/mi cells in a total volume of 2.2 ml in a test tube (18 x 180 ram). The reaction occurred at 50°C for 30 mins with reciprocal shaking (230 strokes/rnin).The percentage degradation of test substance was determined to be 21.4 and 20.1% degradation in 30 mins using 10% and 100% seawater, respectively. Thus, based on percentage degradation, 2,3,5 -trimethylphenol is considered to be inherently biodegradable in nature.

 

On the basis of above results for target chemical 2,3,5 -trimethylphenol (frompeer reviewed journal), it can be concluded that the test substance 2,3,5-trimethylphenol can be expected to be readily biodegradable in nature.

Biodegradation in water and sediemnt

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound 2,3,5 -trimethylphenol (CAS No. 697 -82 -5). If released in to the environment, 18.6% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of 2,3,5-trimethylphenol 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 whereas the half-life period of 2,3,5-trimethylphenol in sediment is estimated to be 337.5 days (8100 hrs). However, as the percentage release of test chemical 2,3,5-trimethylphenol into the sediment is less than 1% (i.e, reported as 0.828%), indicating that the chemical 2,3,5-trimethylphenolis not persistent in sediment.

Biodegradation in soil

The half-life period of 2,3,5-trimethylphenol (CAS No. 697 -82 -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, 80.5% of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of 2,3,5-trimethylphenol in soil is estimated to be 75 days (1800 hrs). Based on this half-life value of 2,3,5-trimethylphenol, 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 2,3,5 -trimethylphenol can be considered to be readily biodegradable in nature.

Bioaccumulation: aquatic / sediment:

Five studies including experimental studies and predicted data from validated models for bioaccumulation (BCF) endpoint of target chemical 2,3,5-trimethylphenol (Cas no. 697-82-5) with structurally similar read across chemical were summarized as follows:

 

First study from predicted model BCFBAF Program (v3.00) model which indicate the estimated bio concentration factor (BCF) for 2,3,5-trimethylphenol is 56.04 L/kg wet-wt which does not exceed the bioconcentration threshold of 2000.Thus it is concluded that 2,3,5-trimethylphenol is not expected to bio accumulate in the aquatic environment.

Other predicted database PBT profiler indicate the Bioaccumulation factor (BCF) for test substance 2,3,5-trimethylphenol was estimated to be 56 L/kg wet-wt at 25 deg.C.

And from Scifinder database suggest the Bioconcentration factor (BCF) for target chemical 2,3,5-trimethylphenol was predicted to be 90.4 at pH 1-10 and temperature 25 deg.C.

Whereas from Chemspider - ACD/PhysChem Suite it become Bioconcentration factor (BCF) for target chemical 2,3,5-trimethylphenol was estimated to be 60.00 at pH 5.5 and 7.4 at temperature 25 deg.C.

All above four predicted results supported by experimental data of read across chemical 2,4,6-trimethylphenol (Cas no. 527-60-6) which suggest Bioaccumulation test was conducted for 6 weeks for determination the bioconcentration factor (BCF) of substance 2,4,6-Trimethylphenol (Cas no.527-60-6) on test organism Cyprinus carpio. The recovery ratio is given- Test water : 1st concentration area : 91.8 %, 2nd concentration area : 84.5 %, Fish : 94.0 %, And Nominal concentrations used in the study as - 1st Concentration area: 0.2 ppm(w/v),　 2nd Concentration area: 0.02 ppm(w/v) and Range finding study was carried out on Rice fish (Oryzias latipes) and the 48 hr LC50 value was found to be 14.3 ppm(w/v).By analytical methods, the limit of detection was found to be-

Test water : 1st concentration area : 17 ppb, 2nd concentration area : 1.9 ppb, Fish : 0.06 ppm.Thus according to static Fish Test the BCF value for test substance 2,4,6-Trimethylphenol (Cas no.527-60-6) was observed to be 6.5<=10 L/kg at dose concentration 0.2 ppm(w/v) and <= 2.7 - (8.1) L/kg at dose concentration 0.02 ppm(w/v) on test organism Cyprinus carpio during 6 weeks period. These values indicate that the substance 2,4,6-Trimethylphenol is not bioaccumulative in fish and food chain.

Thus all available studies for bioaccumulation endpoint concluded that the test substance 2,3,5-trimethylphenol (Cas no. 697-82-5) is expected to be non Bioaccumulative in aquatic environment.

Adsorption / desorption:

Four studies including predicted data from validated model and experimental results for adsorption (KOC) endpoint of test substance 2,3,5-trimethylphenol (CAS no. 697-82-5) with relevant read across which is structurally similar to target were summarized as follows:

 

First estimation using KOCWIN model (v2.00) of EPI suite indicated the Soil Adsorption Coefficient i.e Koc value of 2,3,5-trimethylphenol as Koc 805.2 L/kg (log Koc = 2.905) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 2,3,5-trimethylphenol has a Moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

Another prediction model for target i.e Chemspider - ACD/PhysChem Suite suggest the soil adsorption coefficient i.e Koc value of test substance 2,3,5-trimethylphenol was estimated to be 652.28 (log koc-2.814) at pH 5.5 and pH 7.4 and temp.25 deg.C

Above both results are supported by another prediction database Scifinder, which indicated the soil adsorption coefficient i.e Koc value of test substance 2,3,5-trimethylphenol was estimated to be 874 (Log koc-2.941) at pH 1-7; 872 (Log koc-2.940) at pH 8; 850 (Log koc-2.929) at pH 9; and 677 (Log koc-2.830) at pH 10 at temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 2,3,5-trimethylphenol has moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

Above predictions for the target substance are further supported by experimental result of read across chemical 2,4,6-trimethylphenol (Cas no. 527-60-6) which suggest the Koc of 2,4,6-trimethylphenol is estimated as 700, using a log Kow of 2.73 and a regression-derived equation. This estimated Koc value suggests that 2,4,6-trimethylphenolis expected to have low mobility in soil.

Thus all above available values for adsorption (log KOC) is in the range of 2.814 to 2.941 (L/kg or dimensionless) which gives the final conclusion as target substance 2,3,5-trimethylphenol (CAS no. 697-82-5) is expected to have low mobility in soil and sediment compartment.