p-hydroxyphenylacetic acid

Endpoint summary

Description of key information

Stability:

Hydrolysis:

According to Annex VIII column 2 the study does not need to be conducted because the substance p-hydroxyphenylacetic acid (CAS no.156-38-7) is readily biodegradable.

Biodegradation:

Biodegradation in water:

The test chemical 2-(4-hydroxyphenyl)acetic  acid (CAS no. 156-38-7) undergoes 100 % degradation in batch fixed bed  biofilm reactor  using  coculture of Pseudomonas putida DSM1868

Ralstonia sp. LD35 immobilised on Manville silica beads and on polyurethane foam cubes as inoculums within 50 hrs. On the basis of percent degradability it is concluded that test chemical 2-(4-hydroxyphenyl)acetic  acid (CAS no. 156-38-7) is readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound p-hydroxyphenylacetic acid (CAS No. 156 -38 -7). If released in to the environment, 23.2 % 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 p-hydroxyphenylacetic acid in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.0789 %), indicates that test chemical p-hydroxyphenylacetic acid is not persistent in sediment.

Biodegradation in Soil:

The half-life period of test chemical p-hydroxyphenylacetic acid (CAS No. 156 -38 -7) 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, 76.8 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical p-hydroxyphenylacetic acid in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical p-hydroxyphenylacetic 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 p-hydroxyphenylacetic acid (CAS No. 156-38-7) is 3.162 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical p-hydroxyphenylacetic acid is non bioaccumulative in food chain.

Transport and distribution:

Adsorption/desorption:

The Soil Adsorption Coefficient i.e. Koc value of test chemical p-hydroxyphenylacetic acid (CAS No. 156-38-7) was estimated using EPI suite KOCWIN Program (v2.00) as 37.97 L/kg (log Koc= 1.5795) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical p-hydroxyphenylacetic acid has low sorption to soil and therefore test chemical has moderate migration potential to ground water.

Additional information

Stability:

Hydrolysis:

According to Annex VIII column 2 the study does not need to be conducted because the substance p-hydroxyphenylacetic acid (CAS no.156-38-7) is readily biodegradable

Biodegradation:

Biodegradation in water:

Various experimental studies from different sources for target chemical p-hydroxyphenylacetic acid (CAS no. 156-38-7) have been studied and their results are summarized below for biodegradation in water endpoint.

 

The first experimental study was done from Journal of Biotechnology (2001) in this study An experiment was performed by Lorenzo Bertin et al to determined the biodegradation potential of test chemical 2-(4-hydroxyphenyl)acetic acid (CAS no. 156-38-7). In this experiment coculture of Pseudomonas putida DSM1868 and Ralstonia sp. LD35 was immobilised on Manville silica beads(SB) and on polyurethane foam cubes(PU) was filled in two different fixed bed biofilm reactors. Then synthetic mixture of monoaromatic acid was prepared containing test chemical 2-(4-hydroxyphenyl)acetic acid at concentration of 4.60 mM and other monoaromatic acid at different concentrations. The medium was recycled from the top to the bottom of the SB bioreactor and PU bioreactor at the rate of 25 and 36 ml min1, respectively, for 2–4 days. Two ml samples of the recycled broth were taken out from the sampling port of each bioreactor 4–6 times a day and analysed for the concentration of freely suspended cells of both strains and for the concentration of the test chemical (and related biodegradation aromatic metabolites) In both the reactors test chemical undergoes 100 % degradation within 50 hrs therefore it is concluded that test chemical 2-(4-hydroxyphenyl)acetic acid is readily biodegradable.

 

Second experimental study was done from Journal of Industrial Microbiology (1996) in this study an experiment was performed by N Zouari et al to determine percent degradability of test chemical (2-(4-hydroxyphenyl)acetic acid (CAS n0. 156-38-7) by using different consortia of microorganisms isolated from muds and wastewaters from a local tannery factory, muds from an aerobic domestic wastewater treatment plant and soil samples from a local eucalyptus field(Tunisia). To cultivate microorganisms pretreated olive oil mill effluent (OOME) was used as medium. Since p-OOME contained a low concentration of nitrogen (0.85 g L-Z), some growth factors and a nitrogen source necessary for bacterial growth were added to growth flask and incubated for 2 weeks at 32 oC and different microbial consortia were formed. These different consortia of microorganisms were used as inoculums to degrade phenolic compound containing target chemical p-Hydroxyphenyl acetic acid. The test system for biodegradation experiment was 250 mL culture flask containing minimal salt medium , yeast extract and peptone phenolic compounds mixture containing target chemical p-Hydroxyphenyl acetic acid then it was inoculated by different microbial consortia for 7 days at pH 7.2 and 32 oC temperature and cultures were shaken at 250 rpm. After 7 days of incubation test chemical was analysed by using GC in a gas chromatograph (Shimadzu GC-9A). The phenols were extracted using ethylacetate/acetone (2:1) at pH 2.0. Two milliliters of the solvent were added to 1 ml of culture medium, centrifuged and the organic phase was harvested. GC conditions were: column SE 30 (30 m length, 0.5 mm ID, methyl silicone in the solid phase, injection temperature of 280oC and detector temperature of 300oC.  Percentage of target chemical remained after 7 days of incubation were analysed and results of all microbial consortia are mentioned in table 1. Percentage of test chemical p-Hydroxyphenyl acetic acid remained was 0.0 in most of the flasks inoculated by different consortia of microorganisms. Therefore percent degradation of test chemical p-Hydroxyphenyl acetic acid was determinedto be 100 % in 7 days. Therefore it is concluded that test chemical p-Hydroxyphenyl acetic acid is readily biodegradable.

 

 

Third experimental study was done from Applied and Environmental Microbiology (1998) in this study an experiment was performed by Paula M et al to determined the biodegradation potential of test chemical p-hydroxyphenylacetic acid (CAS no. 156-38-7) for this different cultures were isolated from anaerobic sediments from various geographic locations. A defined mineral salts medium was used for isolation and cultivation of the phenolic compound-degrading strains such as strain PH002 and strain FL05 . Enrichment cultures were prepared from argon-sparged sediment slurry prepared in the defined mineral salts medium (2:1, wt/vol). Ten milliliter portions of this slurry were added to 90-ml portions of argon-sparged medium in 160-ml serum bottles. The bottles were closed with neoprene rubber stoppers. Phenol was added at a starting concentration of 0.5 mM. Cultures were incubated without shaking at 30°C. Then the culture suspensions were transferred to glass screw-cap tubes, and substrates was added from sterile, anaerobic stock solutions to a final concentration of approximately 1 mM. Sterile control and substrate free medium was taken as control. The first sample (time zero) was taken immediately after substrate addition. The tubes were placed in a 30°C water bath, and samples (0.2 ml) were taken periodically with argon-flushed syringes. The samples were quickly pelleted in a microcentrifuge, after which the supernatant was diluted with 0.05 N HCl (1:4) and stored at 4°C before analysis. After analysis it is observed that test chemical is utilized by both the strains in anaerobic condition. Therefore it is concluded that test chemical p-hydroxyphenylacetic acid (CAS no. 156-38-7) is degradable can be utilized by two different strains of bacteria strain PH002 and strain FL0 when it is present in medium as sole carbon source in anaerobic condition .

 

 

The fourth experimental study was done from J. Agric. Food Chem (1997) in this study to determine the biodegradability of test chemical hydroxyphenylacetic acid ( CAS no. 156-38-7) an experiment was performed using BOD bottles . The test chemical was introduced into the BOD bottles as sole carbon sources at a concentration of 2 mg of carbon per bottle. The compounds were added in acetone solutions, and the acetone was evaporated prior to the addition of 02-saturated water. Each bottle received 5 mg of Hudson Collamer silt loam as a source of the microbial inoculum. The bottles were filled with the air-saturated salts solution and closed with glass stoppers. Then bottles were incubated in dark at 25 oC. Sampling was done at regular interval and O2 consumption was measured by using oxygen analyzer, Model 53. Biodegradability of test chemical p-hydroxyphenylacetic acid (156-38-7) was determined by using O2 consumption as parameter, total duration of experiment was 20 days. Test chemical showed more than 5 µg/mL O2 consumption in 2 days.  On the basis of this O2 consumption value it can be concluded that test chemical is biodegradable.

 

 

Fifth study was done from Journal of General Microbiology (1958 ) by R. B. CAIN in this study an experiment was performed to determine the biodegradation potential of test chemical p-Hydroxyphenylacetic acid (CAS no.156-38-7). In this experiment bacteria was isolated from garden soils, manure heaps, or heavily polluted streams by using enrichement culture method. The isolated bacterial species was identified as p-Hydroxyphenylacetic acid. After 7 days of incubation growth was estimated turbidimetrically in a 'Unicam' model S.P. 350 D.G. colorimeter at 530 mp using 10 mm. square glass cells, the optical density measurements. On the basis of growth of bacteria it is concluded that test chemical p-Hydroxyphenylacetic acid (CAS no.156-38-7) is biodegradable.

 

Last experimental study was done from Arch Microbiology (1986) in this study an experiment was performed to determine the degradation potential of test chemical p-Hydroxyphenylacetic acid (CAS no. 156-38-7) in this experiment the anerobic bacteria was isolated from by using enrichment culture in anaerobic condition. The isolated bacteria was initially named as ph01 strain then by using this strain biodegradation of test chemical was performed and latter it was characterized as Desulfobacterium phenolicum which produced H2S gas duration degradation experiment in 10 days and test chemical was also utilized completely by this bacteria. The test chemical p-Hydroxyphenylacetic acid showed 100 % degradation by Desulfobacterium phenolicum sp. (ph01) in anerobic condition 10 days. On the basis of percent degradability it is concluded that test chemical is readily biodegradable.

 

On the basis of all the experimental studies mentioned above it is observed that test chemical p-Hydroxyphenylacetic acid (CAS no. 156-38-7) is degradable by many different bacteria from different sources in various different conditions both aerobically as well as anarobically by using many different parameters. Therefore it is concluded that test chemical is readily biodegradable.

Biodegradation in water and sediments:

Estimation Programs Interface (EPI Suite, 2017) prediction model was run to predict the half-life in water and sediment for the test compound p-hydroxyphenylacetic acid (CAS No.156 -38 -7). If released in to the environment, 23.2 % 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 p-hydroxyphenylacetic acid in sediment is estimated to be 135 days (3240 hrs). However, as the percentage release of test chemical into the sediment is less than 1 % (i.e, reported as 0.0789 %), indicates that test chemical p-hydroxyphenylacetic acid is not persistent in sediment.

Biodegradation in Soil:

The half-life period of test chemical p-hydroxyphenylacetic acid (CAS No. 156 -38 -7) 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, 76.8 % of the chemical will partition into soil according to the Mackay fugacity model level III. The half-life period of test chemical p-hydroxyphenylacetic acid in soil is estimated to be 30 days (720 hrs). Based on this half-life value of test chemical p-hydroxyphenylacetic 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:

Bioaccumulation: aquatic/sediments:

Various predicted data for the target compoundp-hydroxyphenylacetic acid (CAS No. 156-38-7) and supporting weight of evidence studies for its structurally similar read across chemical were reviewed for the bioaccumulation end point which are summarized as below:

The first predicted data study was done by using BCFBAF Program (v3.00) model of Estimation Program Interface (EPI suite 2018) the estimated bio concentration factor (BCF) for p-hydroxyphenylacetic acid (CAS No. 156-38-7) is 3.162 L/kg wet-wt at 25 deg. c which does not exceed the bioconcentration threshold of 2000. Therefore it is concluded that test chemical p-hydroxyphenylacetic acid is non bioaccumulative in food chain.

In another predicted data study the Bioconcentration factor (BCF) for test chemical p-hydroxyphenylacetic acid (CAS No: 156-38-7) was predicted in aquatic organisms by Scifinder database of American Chemical Society (ACS, 2017) at pH 1-10 and temperature 25 °C .The Bioconcentration factor (BCF) of test substance p-hydroxyphenylacetic acid at temperature 25 °C was estimated to be in range 1.46 - 1.97 dimensionless at pH range 1-4 and at pH range 5-10 BCF value estimated was 1.0 dimensionless. These BCF values at pH 1-10 and temperature 25 °C suggests that the test chemical p-hydroxyphenylacetic acid is non bioaccumulative in aquatic organisms.

 

In next predicted data study the Bioconcentration factor (BCF) for test chemical p-hydroxyphenylacetic acid (CAS No: 156-38-7) was predicted in aquatic organisms by Chemspider- ACD/PhysChem Suite of Royal Society of Chemistry (RCS, 2017) at pH 5.5 and pH 7.4.The Bioconcentration factor (BCF) of test substance p-hydroxyphenylacetic acid at pH 5.5 and 7.4 was  estimated to be 1.0 dimensionless . This BCF value suggests that the test chemical p-hydroxyphenylacetic acid is non bioaccumulative in aquatic organisms.

 

Last predicted data stud was done 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)  the bioaccumulation i.e BCF for test substance p-hydroxyphenylacetic acid (CAS no.156 -38 -7) was estimated to be 4.15 dimensionless . The predicted BCF result was based on the 5 OECD principles. Thus based on the result it is concluded that the test substance p-hydroxyphenylacetic acid is non-bioaccumulative in nature, because the bioconcentration factor in fish is less than 2000.

Next study was experimental study done for structurally similar read across chemical 4-chlorophenoxyacetic acid in this study according to authoritative database the BCF value estimated was 3 dimensionless by,using a log Kow of 2.25 and a regression derived equation. This BCF value suggests the potential for bioconcentration in aquatic organisms is low.

On the basis of above results for target chemical p-hydroxyphenylacetic acid (CAS No. 156-38-7) (from EPI suite, Sci Finder database, Chemspider and CompTox Chemistry Dashboard 2017) and for its read across chemicals (From HSDB) it can be concluded that the BCF value of test substancep-hydroxyphenylacetic acid (CAS No. 156-38-7) ranges from 1 to 4.15 dimensionless which does not exceed the bioconcentration threshold of 2000, indicating that the chemicalp-hydroxyphenylacetic acid (CAS No. 156-38-7) is expected to be nonbioaccumulative in the food chain.

Transport and distribution:

Adsorption/desorption:

Various predicted data studies for target chemical p-hydroxyphenylacetic acid (CAS No. 156-38-7) and experimental study for its structurally and functionally similar read across chemicals have been conducted and their results are summarized below for adsorption endpoint.

 

In first predicted data study the Soil Adsorption Coefficient i.e. Koc value of test chemical p-hydroxyphenylacetic acid (CAS No. 156-38-7) was estimated using Estimation Program Interface (EPI suite, 2018) KOCWIN Program (v2.00) as 37.97 L/kg (log Koc= 1.5795) by means of MCI method at 25 deg. C.  This log Koc value indicates that test chemical p-hydroxyphenylacetic acid has low sorption to soil and therefore test chemical has moderate migration potential to ground water.

 

Another predicted data study was done by using Sci Finder database of Americal chemical Society (ACS, 2017) the soil adsorption co-efficient i.e., Koc value of test chemical p-hydroxyphenylacetic acid was estimated to be 1.0 dimensionless (log Koc = 0) at pH range 7-10 at temperature 25 deg.c. this value suggests that this test chemical has negligible sorption to soil and sediments ane therefore has rapid migration potential to ground water.

 

Next study was done by using Chemspider-ACD/Phy chem suite of Royal Society of Chemistry (RCS, 2017) in this study the soil adsorption co-efficient i.e., Koc value of test substance p-hydroxyphenylacetic acid  was estimated to be 6.40 dimensionless (log Koc= 0.8061) at pH 5.5 and 1.0 dimensionless (Log Koc= 0.0) at pH 7.4 and temperature 25 deg.C These Koc values at different pH indicates that the chemical p-hydroxyphenylacetic acid has negligible sorption to soil and sediments and therefore has rapid migration potential to ground water.

 

Last predicted data study was done 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)  the adsorption coefficient i.e KOC for test substance p-hydroxyphenylacetic acid (CAS no. 156 -38 -7) was estimated to be 63.8 L/kg (log Koc = 1.8048) .The predicted KOC result based on the 5 OECD principles. Thus based on the result it is concluded that the test substance p-hydroxyphenylacetic acid has a low sorption to soil and sediment and therefore has moderate migration potential to ground water.

 

Next study was experimental study done by SSS (2017) in this study the adsorption coefficient Koc in soil and in sewage sludge of read across chemical 4-methoxyphenylacetic acid (CAS No.104-01-8) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to structural similarity with the read across substance and calibration graph prepared. The reference substances were xylene, ethylbenzene and toluene having Koc value ranging from 2.369 to 2.649. The Log Koc value was determined to be 1.15385 ± 0.0029 at 25°C. The results indicate that the read across chemical 4-methoxyphenylacetic acid (CAS No. 104-01-8) is likely to show low tendency of sorption to soil and sediment and show moderate migration potential to groundwater.

 

In another experimental study Koc value was determined by using a structure estimation method based on molecular connectivity indices, the Koc for read across chemical 4-chlorophenoxy acetic acid was estimated to be 18 dimensionless this estimated Koc value suggests that 4-chlorophenoxy acetic acid is expected to have very high mobility in soil and negligible sorption to soil and sediments.

 

On the basis of above results for target chemical p-hydroxyphenylacetic acid (CAS No. 156-38-7)(from EPI suite, Sci Finder database, Comptox chemistry dashboard and Chemspider 2017) and for its read across chemicals (From authoritative database HSDB) it can be concluded that the log Koc value ofp-hydroxyphenylacetic acidranges from 0.0 to 1.8048 indicating that the chemicalp-hydroxyphenylacetic acid has negligible to low sorption to soil and sediment and therefore it has rapid to moderate migration potential to ground water.