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Environmental fate & pathways

Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Data is from computational model developed by USEPA
Qualifier:
according to
Guideline:
other: Modeling database
Principles of method if other than guideline:
KOCWIN Program (v2.00)
GLP compliance:
not specified
Type of method:
other: estimation
Media:
soil
Radiolabelling:
not specified
Test temperature:
25 deg C
Analytical monitoring:
not specified
Key result
Type:
Koc
Value:
666.7 L/kg
Temp.:
25 °C
Remarks on result:
other: log Koc= 2.8239Estimated via MCI method
Transformation products:
not specified

KOCWIN Program (v2.00) Results:

==============================

SMILES : O=C(C=CC1=C(CCCC1(C)C)C)C

CHEM : Ionone

MOL FOR: C13 H20 O1

MOL WT : 192.30

--------------------------- KOCWIN v2.00 Results ---------------------------

Koc Estimate from MCI:

---------------------

First Order Molecular Connectivity Index ........... : 6.432

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 3.9530

Fragment Correction(s):

1 Ketone (-C-CO-C-) ................... : -1.1290

Corrected Log Koc .................................. : 2.8240

Estimated Koc: 666.7 L/kg <===========

Validity criteria fulfilled:
not specified
Conclusions:
The Soil Adsorption Coefficient i.e Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 666.77 L/kg (log Koc= 2.8239) by means of MCI method at 25 deg.C. This Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.
Executive summary:

The Soil Adsorption Coefficient i.e Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 666.77 L/kg (log Koc= 2.8239)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

Description of key information

The Soil Adsorption Coefficient i.e Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 666.77 L/kg (log Koc= 2.8239)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

Key value for chemical safety assessment

Koc at 20 °C:
666.77

Additional information

Various experimental studies has been investigated along with the predicted data for the test chemical for reviewing the soil adsorption endpoint which have been summarized as below;

 

The Soil Adsorption Coefficient i.e Koc value of test chemical was estimated using EPI suite KOCWIN Program (v2.00) as 666.77 L/kg (log Koc= 2.8239)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow migration potential to groundwater.

 

The above result is supported by the adsorption coefficient Koc study of test chemical in soil and in sewage sludge by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately pipetting 4 microliter of test item and diluted with Acetonitrile up to 10 ml. Thus, the test solution concentration was 354.4 mg/l. The pH of test substance was 7.2. 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. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared or chosen according to functionalyl similarity with the test substance and calibration graph prepared. The reference substances were Xylene, Ethylbenzene, Toluene, Naphthalene, phenanthrene having Koc value ranging from 2.369 to 4.09 The Log Koc value of test substance was determined to be 3.456±0.000 at 25°C. This log Koc value indicates that the substance has aModerate sorption to soils and sedimentand therefore haveslow migration potential to round water.

 

In the next adsorption study, the Koc value for test chemical estimated was 670 dimensionless and log Koc is 2.8260 this log Koc value suggests that test chemical is expected to have moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

The above results are further supported by the Adsorption study conducted for estimating the adsorption coefficient (Koc) value of test chemical. The adorption coefficient (Koc) value was calculated using a structure estimation method based on molecular connectivity indices. The adsorption coefficient (Koc) value of test substance was estimated to be 670 (Log Koc = 2.826). This Koc value indicates that the substance has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

 

Based on the available data,it can be concluded that the testchemical has a moderate sorption to soil and sediment and therefore have slow migration potential to ground water.

[LogKoc: 2.8239]