Hexachlorocyclopentadiene

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Justification for type of information:

Although the experiment was not performed in accordance a validated method, the experiment measures some of the parameters measured by these protocols. The data has been deemed sufficient to include in a European Risk Assessment for the substance.

Principles of method if other than guideline:

Measurement of proportion of 14C labelled hexachlorocyclopentadiene adsorbed onto a loam soil as measured by liquid scintillation. The experiment was performed at three different initial concentrations of hexachlorocyclopentadiene and the samples were equilibrated for 24 hours before sampling.

GLP compliance:

no

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

25 degC

Analytical monitoring:

yes

Details on sampling:

The whole experiment was centrifuged at 1000 rpm for 20 minutes. A 2 mL aliquot of supernatant was removed and added to a 15 mL aliquot of scintillation cocktail (2,5-diphenyloxazole (5.0g), 1,4-bis[2-(4-methyl-5-phenyloxazolyl)]benzene (0.1 g), Triton X-100 (1L) and toluene (1L).

Matrix no.:

#1

Matrix type:

loam

% Clay:

ca. 11

% Silt:

ca. 28

% Sand:

ca. 61

% Org. carbon:

ca. 8.7

pH:

ca. 5.1

CEC:

ca. 10.3

Details on matrix:

Soil taken from 0 to 6 inch depth near Plymouth, North Carolina. Soil seived to pass 2 mm screen, mixed, freeze dried and stored in sealed containers.

Details on test conditions:

Experiment performed in 50 mL glass stoppered bottles (filled to capacity to avoid losses by evaporation). Placed in rotating shaker at room temperature for 24 hours. (No information regarding light/dark)

Sample No.:

#1

Type:

Koc

Value:

ca. 18 482 L/kg

Temp.:

25 °C

% Org. carbon:

ca. 8.7

Remarks on result:

other:

Remarks:

Average of duplicate experiments

Sample No.:

#2

Type:

Koc

Value:

ca. 23 256 L/kg

Temp.:

25 °C

% Org. carbon:

ca. 8.7

Remarks on result:

other:

Remarks:

Average of duplicate experiments

Sample No.:

#3

Type:

Koc

Value:

ca. 34 483 L/kg

Temp.:

25 °C

% Org. carbon:

ca. 8.7

Remarks on result:

other:

Remarks:

Average of duplicate experiments

Key result

Sample No.:

#4

Type:

Koc

Value:

ca. 25 407 L/kg

Temp.:

25 °C

% Org. carbon:

ca. 8.7

Remarks on result:

other:

Remarks:

Average of 6 experimental results

Adsorption and desorption constants:

Kd = 2203 L/kg
Koc = 25407 L/kg
log Koc = 4.40

Transformation products:

not measured

Validity criteria fulfilled:

not applicable

Conclusions:

Kd = 2203 L/kg
Koc = 25407 L/kg
log Koc = 4.40

Executive summary:

The adsorption onto Cape Fear loam soil was measured after equilibration at 25 degC for 24hrs. The following parameters were measured

Kd = 2203 L/kg

Koc = 25407 L/kg

log Koc = 4.40

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Principles of method if other than guideline:

Not specified

GLP compliance:

not specified

Sample No.:

#1

Type:

Koc

Value:

ca. 4 256 L/kg

Validity criteria fulfilled:

not applicable

Conclusions:

KOC = 4265 L/kg

Reference 3

Endpoint:

adsorption / desorption, other

Type of information:

(Q)SAR

Remarks:

EPIWIN

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

QSAR calculation from a secondary source and used in a weight-of-evidence approach.

Principles of method if other than guideline:

QSAR Calculation

GLP compliance:

no

Type of method:

other:

Remarks:

QSAR using EPIWIN

Sample No.:

#1

Type:

Koc

Value:

ca. 1 667 L/kg

Validity criteria fulfilled:

not applicable

Conclusions:

KOC = 1667 L/kg

Reference 4

Endpoint:

adsorption / desorption, other

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Justification for type of information:

QSAR calculation from a secondary source and used in a weight-of-evidence approach.

Principles of method if other than guideline:

QSAR calculation

Sample No.:

#1

Type:

Koc

Value:

ca. 15 000 L/kg

Transformation products:

not measured

Validity criteria fulfilled:

not applicable

Conclusions:

KOC = 15,000 L kg-1

Description of key information

None of the studies investigating the adsorption/desorption of Hexachlorocyclopentadiene could be used a key study due to significant methodological deficiencies or unavailability of the primary source of the study. Therefore a weight of evidence approach was used considering four available studies as weight of evidence. The average of the values measured or calculated in the studies was reported as the adsorption/desorption coefficient of Hexachlorocyclopentadiene:

Koc at 20°C = 11,584

Log Koc at 20°C = 4.06

Key value for chemical safety assessment

Koc at 20 °C:

11 584

Additional information

[LogKoc: 4.06]