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Colloid properties in groundwaters from crystalline formations

Technical Report:

Abstract

Colloids are present in all groundwaters. The role they may play in the migration of radionuclides in the geosphere must be studied. Colloid sampling and characterisation campaigns have been carried out in Switzerland. On the bases of the results from studies in various areas, a consistent picture is emerging. The groundwater colloids in crystalline formations are predominantly comprised of phyllosilicates and silica originating from the aquifer rock. Under constant hydrogeochemical conditions, the colloid concentration is not expected to exceed 100 ng.ml{sup -1} when the calcium concentration is greater than 10{sup -4}. However, under transient chemical or physical conditions, such as geothermal or tectonic activity, colloid generation may be enhanced and the colloid concentration may reach 10 {mu}g.ml{sup -1} or more, if both the calcium and sodium concentrations are low. In the Nagra Crystalline Reference Water the expected colloid concentration is <100 ng.ml{sup -1}. This can be compared, for example, to a colloid concentration of about 10 ng.ml{sup -1} found in Zurzach water. The small colloid concentration in the reference water is a consequence of an attachment factor for clay colloids close to 1. A model indicates that at pH 8, the nuclide partition coefficients between water and colloid (K{sub p})  More>>
Authors:
Degueldre, C A [1] 
  1. Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Publication Date:
Sep 01, 1994
Product Type:
Technical Report
Report Number:
PSI-94-21
Reference Number:
SCA: 540230; 052002; PA: AIX-26:010179; EDB-95:031302; SN: 95001323619
Resource Relation:
Other Information: PBD: Sep 1994
Subject:
54 ENVIRONMENTAL SCIENCES; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; GROUND WATER; COLLOIDS; SWITZERLAND; PLUTONIC ROCKS; CHEMISORPTION; EXPERIMENTAL DATA; QUANTITATIVE CHEMICAL ANALYSIS; RADIONUCLIDE MIGRATION; SAMPLING; WATER CHEMISTRY; 540230; 052002; RADIOACTIVE MATERIALS MONITORING AND TRANSPORT; WASTE DISPOSAL AND STORAGE
OSTI ID:
10113026
Research Organizations:
Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Country of Origin:
Switzerland
Language:
English
Other Identifying Numbers:
Other: ON: DE95612389; TRN: CH9400410010179
Availability:
OSTI; NTIS; INIS
Submitting Site:
CHN
Size:
104 p.
Announcement Date:
Jun 30, 2005

Technical Report:

Citation Formats

Degueldre, C A. Colloid properties in groundwaters from crystalline formations. Switzerland: N. p., 1994. Web.
Degueldre, C A. Colloid properties in groundwaters from crystalline formations. Switzerland.
Degueldre, C A. 1994. "Colloid properties in groundwaters from crystalline formations." Switzerland.
@misc{etde_10113026,
title = {Colloid properties in groundwaters from crystalline formations}
author = {Degueldre, C A}
abstractNote = {Colloids are present in all groundwaters. The role they may play in the migration of radionuclides in the geosphere must be studied. Colloid sampling and characterisation campaigns have been carried out in Switzerland. On the bases of the results from studies in various areas, a consistent picture is emerging. The groundwater colloids in crystalline formations are predominantly comprised of phyllosilicates and silica originating from the aquifer rock. Under constant hydrogeochemical conditions, the colloid concentration is not expected to exceed 100 ng.ml{sup -1} when the calcium concentration is greater than 10{sup -4}. However, under transient chemical or physical conditions, such as geothermal or tectonic activity, colloid generation may be enhanced and the colloid concentration may reach 10 {mu}g.ml{sup -1} or more, if both the calcium and sodium concentrations are low. In the Nagra Crystalline Reference Water the expected colloid concentration is <100 ng.ml{sup -1}. This can be compared, for example, to a colloid concentration of about 10 ng.ml{sup -1} found in Zurzach water. The small colloid concentration in the reference water is a consequence of an attachment factor for clay colloids close to 1. A model indicates that at pH 8, the nuclide partition coefficients between water and colloid (K{sub p}) must be smaller than 10{sup 7} ml.g{sup -1} if sorption takes place by surface complexation on colloids, = AIOH active groups forming the dominant sorption sites. This pragmatic model is based on the competition between the formation of nuclide hydroxo complexes in solution and their sorption on colloids. Experimental nuclide sorption data on colloids are compared with those obtained by applying this model.}
place = {Switzerland}
year = {1994}
month = {Sep}
}