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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Data is from experimental study report.
Qualifier:
according to guideline
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Principles of method if other than guideline:
To determine Adsorption coefficient (KOC) on soil and on sewage sludge of the 4-methoxyphenylacetic acid (CAS No. 104-01-8) using HPLC.
GLP compliance:
no
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Specific details on test material used for the study:
- IUPAC name: (4-methoxyphenyl)acetic acid
- Name of the test material: 4-methoxyphenylacetic acid
- Molecular formula: C9H10O3
- Molecular weight: 166.175 g/mol
- SMILES: c1(ccc(OC)cc1)CC(O)=O
- InChI: 1S/C9H10O3/c1-12-8-4-2-7(3-5-8)6-9(10)11/h2-5H,6H2,1H3,(H,10,11)
- Substance type: Organic
- Physical state: Solid

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:L142811602
- Expiration date of the lot/batch:01-01-21

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:Ambient Temp (23 to 27°C) (Keep container tightly closed in a dry & well ventilated place. Store in cool place. Do not expose to air, light & moisture.)
- Stability under test conditions:Stable in recommended storage conditions
Radiolabelling:
not specified
Test temperature:
25 deg.C
Details on study design: HPLC method:
The solutions of the test substance and reference substances were prepared in the mobile phase. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed.
Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor.

Operating Conditions:
HPLC Model No. : Agilent Technologies,1260 Infinity
Flow Rate : 1.0ml/min
Column : ZORBAX Eclipse Plus C18, 4.6×100mm, 3.5 μm
Mobile phase : Acetonitrile: water (55:45)
Temperature : 25°C
Detector : Diode Array Detector @210nm
Injector : Autosampler
Injector volume : 10μl
Data Acquisition software : ChemStationOpen lab Control Panel

Preparation of Reference substances:
The reference substances, xylene, ethylbenzene and toluene were chosen having Koc value range from 2.369 to
2.649. Individual solutions of these ten substances were prepared in Acetonitrile : water (55:45) with
concentrations of 500 mg/l.
Urea (at concentration of 500 mg/l) was used as an unretained compound for the determination of the “dead
time” t0.
K=tR -t0
t0
where
k= capacity factor,
tR= retention time of test substance and reference substance.
t0=retention time of Urea.
Details on test conditions:
TEST CONDITIONS
- pH: 6.98

TEST SYSTEM
- Method of preparation of test solution:A test item solution was prepared by accurately weighing 7 mg of test item and diluted with acetonitrile up to 10 ml. Thus, the stock solution was diluted to yield a final concentration of 70 mg/l.
Key result
Type:
log Koc
Value:
1.154 dimensionless
pH:
6.98
Temp.:
25 °C
Remarks on result:
other: Log Koc reported as 1.15385 ± 0.0029
Transformation products:
not specified

The Adsorption coefficient (KOC) on soil and on sewage sludge of the 4-methoxyphenylacetic acid (CAS No.104-01-8)was found to be 1.15385 ± 0.0029 at 25°C.

Reference

substance

Log Koc

tR1

tR2

tR3

MeantR ± S.D.

k

Log k

Urea

-

0.887

0.887

0.888

0.887±0.00057

-

-

Xylene

2.58

6.241

6.232

-

6.2365±0.0063

6.031

0.7804

Ethylbenzene

2.649

6.359

6.355

-

6.357±0.0028

6.167

0.7901

Toluene

2.369

4.378

4.382

-

4.38±0.0028

3.938

0.5953

Test substance

3-methoxyacetophenone

K

Log k

Log Koc

by Generalized Calibration

Graph

Mean of Log Koc ± S.D.

tR1

1.295

0.459977

-0.337263

1.151775

1.15385 ±0.0029

tR2

1.298

0.463359

-0.334081

1.155924

Validity criteria fulfilled:
not specified
Conclusions:
The Adsorption Coefficient of test substance 4-methoxyphenylacetic acid (CAS No. 104-01-8) was determined as per the HPLC method (OECD Guideline-121). The Log Koc value was found to be 1.15385 ± 0.0029 at 25°C.
Executive summary:

The adsorption coefficient Koc in soil and in sewage sludge 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 test 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 found to be 1.15385 ± 0.0029 at 25°C. The results indicate that the 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.

Description of key information

The adsorption coefficient Koc in soil and in sewage sludge 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 test 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 found to be 1.15385 ± 0.0029 at 25°C. The results indicate that the 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.

Key value for chemical safety assessment

Koc at 20 °C:
14.251

Additional information

For adsorption in soil/sediment endpoint 5 studies for test chemical 4-methoxyphenylacetic acid (Cas no. 104-01-8) with read across chemical which is 60-70% structurally similar to target were summarised as follows:

Study 1:

The experiment was conducted by UERL; 2017 to determine Adsorption coefficient (KOC) on soil and on sewage sludge of the4-methoxyphenylacetic acid(CAS No.104-01-8) using HPLC.

According to study the adsorption coefficient Koc in soil and in sewage sludge 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 test substance and calibration graph prepared. The reference substances were xylene, ethylbenzene and toluene having Koc value ranging from 2.369 to 2.649. TheLog Kocvalue was found to be1.15385 ± 0.0029 at 25°C. The results indicate that the 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.

Study 2:

The Soil Adsorption Coefficient i.e Koc value of 4-methoxyphenylacetic acid was estimated using EPI suite  KOCWIN Program (v2.00) program as Koc 18.94 L/kg(log Koc=1.277)  by means of MCI method at 25 deg.C, indicating that it is has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Study 3:

SciFinder, American Chemical Society (ACS); 2017 prediction database indicated the soil adsorption coefficient i.e Koc value of target substance 4-methoxyphenylacetic acid was estimated to be 112 L/Kg i.e Log Koc= 2.049 at pH 1, 111.0 i.e Koc=2.045 at pH 2, 108.0 i.e Log Koc=2.033 at pH 3, 82.4 i.e Log Koc=1.915 at pH 4, 32.1 i.e Log Koc=1.389 at pH 5, 3.06 i.e Log Koc=0.4857 at pH 6, 1.0 i.e Log Koc=0, at pH 6-10 and temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 4-methoxyphenylacetic acid has a low sorption to soil and sediment and therefore have rapid migration potential to groundwater. 

Study 4:

Chemspider predicted database the soil adsorption coefficient i.e Koc value of test substance (4-methoxyphenyl)acetic acid was estimated to be 1 13.81 i.e Log Koc= 1.140 at pH 5.5 and 1.00 i.e Log Koc=0 at pH 7.4 at temp.25 deg.C .This Koc value indicates that the substance (4-methoxyphenyl)acetic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

All studies i.e 2, 3 and 4 based on the prediction results also supports the experimental study 1.

Study 5:

In final study based on the authorative database source i.e HSDB database; 2017 for read across chemical 4-chlorophenoxy acetic acid (Cas no. 122-88-3) indicate Koc of 4-chlorophenoxyacetic acid is estimated as 18, Using a structure estimation method based on molecular connectivity indices, this estimated Koc value suggests that 4-chlorophenoxy acetic acid is expected to have very high mobility in soil.

Read across study also give assistance to experimental and predicted results of the target chemical.

Thus all above experimental and other supported reports arrive at a judgement as the test substance 4-methoxyphenylacetic acid (Cas no. 104-01-8) has high mobility in soil/sediment.

[LogKoc: 1.15385]

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