Potassium perchlorate

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The materials and methods are well described in the publication.

GLP compliance:

no

Type of method:

other: exposure of soils to low and high perchlorate concentrations, determination of the perchlorate concentration by ion chromatography

Media:

soil

Specific details on test material used for the study:

Low lever exposure:
Triplicate 5.0 g portions of each soil were dispensed into 50 mL centrifuge tubes. Deionized water (25.0 mL) and a solution (670 µg/mL) of ammonium perchlorate (25.0 µL) were added. The resulting solution of NH4CIO4(aq) contained 670 ng/mL (6.8 µM) perchlorate. The tubes were capped and rotated end-over-end for 2 days at ambient temperature to permit equilibration. After centrifuging the tubes at 3000g for 90 - 120 min the centrifugates were decanted into sterile tubes immediately. The tubes were capped and stored at 5 °C pending analysis.

High level exposure:
Triplicate 5.0 g portions of each soil were dispensed into 250 mL centrifuge tubes. Deionized water (250 mL) and a 5.0 M solution of sodium perchlorate (10.0 mL) were added. The resulting solution of NH4CIO4(aq) containcd 20 g/L (0.20 M) perchlorate. The tubes were capped and rotated end-over-end for at least 3 days at ambient temperature to permit equilibration. The tubes were centrifuged at 3000-3500g for 90 - 120 min once a day.

Radiolabelling:

no

Key result

Type:

Koc

Value:

<= 100 dimensionless

Conclusions:

Based on the tests on 38 different soils it can be stated that perchlorate salts do not sorb to soils.
No Koc is reported in the study.

Executive summary:

Low lever exposure:

For the study 38 different soils, minerals or dusts were tested. 5.0 g of each material were subjected to 25 mL of an 6.8 µM aqueous ammonium perchlorate solution (containing 670 ng/mL perchlorate). More than 90% of the perchlorated remained in the aqueous phase (determined by ion chromatography).

High level exposure:

For the determination of forced perchlorate anion exchange (PAEC) 5.0 g of each material were subjected to 250 mL of a 0.20 M aqueous sodium perchlorate solution. The samples were washed with deionized water until perchlorate concentrations fell below 20 ng/mL. After drying the residua were leached with 15 mL of 0.1 M sodium hydroxide solution. The calculated PAEC based on the determination of perchlorate concentraion in the leachates by ion chromatography ranged from 4 to 150 nmol/g.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

calculation (if not (Q)SAR)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

EPI Suite is accepted as program for calculating the absorption coefficient.

Principles of method if other than guideline:

The value was calculated using KOCWIN v2.00.
Experimental determination is technically not feasible as potassium perchlorate is inorganic.

Type of method:

other: calculation

Media:

soil

Radiolabelling:

no

Key result

Type:

Koc

Value:

42.89 L/kg

Temp.:

20 °C

Key result

Type:

log Koc

Value:

1.642 dimensionless

Temp.:

20 °C

CAS Number: 7778-74-7

SMILES : O(K)CL(=O)(=O)=O

CHEM   : POTASSIUM PERCHLORATE

MOL FOR: CL1 O4 K1

MOL WT : 138.55

Soil Adsorption Coefficient (KOCWIN v2.00):

  *** WARNING: Inorganic Coumpound (Outside Estimation Domain) **

  *** WARNING: Estimation NOT VALID **

     Koc    :  43.89  L/kg (MCI method)

     Log Koc:  1.642       (MCI method)

     Koc    :  5.862E-007  L/kg (Kow method)

     Log Koc:  -6.232      (Kow method)

Conclusions:

Calculation of Koc made with KOCWIN v2.00 delivers a Koc of 43.89

Description of key information

Based on the tests on 38 different soils it can be stated that perchlorate salts do not sorb to soils. Potassium perchlorate is considered not to sorb to soils.

Koc and Log Koc are determined by calculation using KOCWIN v2.00.

Key value for chemical safety assessment

Koc at 20 °C:

43.89

Additional information

[LogKoc: 1.642]