Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Reliability rating was 1 because study followed OECD 121 test guidelines and was carried out under GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
GLP compliance:
yes
Type of method:
HPLC estimation method
Media:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Radiolabelling:
no

Study design

Test temperature:
25 C

HPLC method

Details on study design: HPLC method:
The sorption behaviour of the test substance on soil can be investigated using high performance liquid chromatography (HPLC). This is performed on commercially available analytical columns packed with a solid phase containing a moderately polar stationary phase with lipophilic and polar moieties (e.g. cyano-propyl bonded phase). The chemicals injected onto the column move along it by partitioning between the mobile phase and the stationary phase. The velocity of each component thereby depends on the degree of adsorption on the stationary phase. The dual nature of the stationary phase allows for interaction of polar and apolar parts of a molecule in a similar way as is the case for soil. This enables the relationship between the retention time on such a column and the adsorption coefficient on the organic parts of the soil to be established. The adsorption coefficient is deduced from the capacity factor (k) given by:

k = ( tr-to ) / to

where tr is the measured retention time of sample or reference
and to is the retention time of the internal deadtime standard

In order to correlate the measured capacity factor (k) of the test material with its Koc, six reference materials were selected from a list of recommended compounds. These reference compounds were selected to have log10Koc values between 1.3 and 5.6. An internal standard (formamide) with no retention on the HPLC column was used to determine the deadtime of the HPLC system.

The six reference standards were acetanilide, nitrobenzene, naphthalene, 2-methylnaphthalene, anthracene and DDT which had known log Koc values of 1.3, 2.4, 2.8, 3.9, 4.4 and 5.6, respectively.
A solution of MCP2484 (21.8 mg/l in HPLC mobile phase, and also containing I.D.S. at the same concentration as in the reference mixture) was prepared and chromatographed in duplicate, bracketed by samples of the reference mixture, using the following conditions:

HPLC system was as follows:

Instrument: Agilent 1200 Series Liquid Chromatograph System
Column: HyperClone CN (CPS) (25 cm x 4.6 mm internal diameter)
Colum TemP: 25 C
Mobile phase: MeOH:THF:water (30:25:45 v/v/v)
Flow rate: 1 ml/min
Injection volume: 100 microliter
Detector: UV detection at 210 nm

Reference standards and MCP 2484 were run on HPLC system and retention times plotted on a calibration curve against log Koc values for the standards. By interpolation from the curve, the log Koc value for MCP 2484 was extrapolated.

Batch equilibrium or other method

Analytical monitoring:
yes

Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
> 6
Temp.:
25 °C
Remarks on result:
other: OECD 121 HPLC method

Results: HPLC method

Details on results (HPLC method):
Results from the HPLC analysis produced a log Kow- capacity factor (based on relative retention times) calibration curve that was defined by the relationship log Kow = 4.18 log k +4.55
where k was the capacity factor = (tr -t o) / to

Based on retention times, MCP 2484 showed a capacity factor , k = 3.414-4.283 which corresponded to log Koc of 6.8 to 7.2,
hence, overall, it was concluded that the log Koc > 6

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Using soil adsorption OECD 121 (HPLC) method, the test substance was found to have a log Koc vlaue of greater than 6 at 25 C.
Executive summary:

The soil sorption coefficient (Koc) was determined using the OECD 121 HPLC method. The log Koc value was found to be greater than 6, which indicates that the test substance adsorbs to soil.

Discussion

Sediment partition coefficient (Koc) was experimentally determined using the soil adsorption OECD 121 HPLC test method. The log Koc value was greater than 6 for the submission substance based on the HPLC retention time-capacity factor determination using reference standards and extrapolation. Overall, the submission substance components have the potential to significantly sorb to organic matter in sediment.

 

Conclusion: The submission substance has the potential to sorb to organic matter to a large extent.