Related Experiment Video
Updated: Jul 20, 2026
12:03
Two-Dimensional Visualization and Quantification of Labile, Inorganic Plant Nutrients and Contaminants in Soil
Published on: September 1, 2020
Trace elements in rock salt and their bioavailability estimated from solubility in acid
Georg Steinhauser1, Johannes H Sterba, Karin Poljanc
1Vienna University of Technology, Atominstitut der Osterreichischen Universitäten, Stadionallee 2, 1020 Vienna, Austria. georg.steinhauser@ati.ac.at
Summary
This study analyzed trace elements in rock salt from various countries. Most essential trace elements like iron are not bioavailable, meaning rock salt does not significantly contribute to daily nutrient intake.
Area of Science:
- Geochemistry
- Nutritional Science
- Analytical Chemistry
Background:
- Rock salt is a common food additive and seasoning.
- Understanding its trace element composition is crucial for nutritional assessment.
- Bioavailability of minerals in food sources impacts human health.
Purpose of the Study:
- To investigate the trace element content of commercially available rock salt samples.
- To assess the bioavailability of these detected trace elements.
- To determine if rock salt can significantly contribute to the recommended daily intake of metal trace elements.
Main Methods:
- Instrumental neutron activation analysis (INAA) was used to detect trace elements.
- Samples were dissolved in diluted hydrochloric acid to simulate stomach acid.
- Filtrates were analyzed after evaporation to estimate bioavailability.
Main Results:
- 18 rock salt samples from six countries were analyzed.
- A wide range of trace elements (e.g., Al, Fe, Th, Zn) were detected.
- Bioavailability assessment showed that essential elements like iron are largely insoluble and thus not bioavailable.
- Thorium showed partial bioavailability in two samples.
Conclusions:
- Rock salt does not significantly contribute to the recommended daily intake of metal trace elements.
- The bioavailability of trace elements in rock salt is generally low due to their insoluble forms.
- Further research may be needed for specific elements like thorium.
Related Concept Videos
03:46Qualitative Analysis
For solutions containing mixtures of different cations, the identity of each cation can be determined by qualitative analysis. This technique involves a series of selective precipitations with different chemical reagents, each reaction producing a characteristic precipitate for a specific group of cations. Metal ions within a group are further separated by varying the pH, heating the mixture to redissolve a precipitate, or adding other reagents to form complex ions.
For instance, group IV...
For instance, group IV...
01:09Solubility Equilibria: Overview
When a substance such as sodium chloride is added to water, it dissolves, forming an aqueous solution. The extent of dissolution is called solubility. The process of dissolution can exist in equilibrium, just like other chemical processes. Solubility equilibria are also called precipitation equilibria because the process of solubility can be reversible. The reverse of the solubility process is called precipitation.
Solubility is important in biological and environmental processes. A notable...
Solubility is important in biological and environmental processes. A notable...
04:01Factors Affecting Solubility
Compared with pure water, the solubility of an ionic compound is less in aqueous solutions containing a common ion (one also produced by dissolution of the ionic compound). This is an example of a phenomenon known as the common ion effect, which is a consequence of the law of mass action that may be explained using Le Chȃtelier’s principle. Consider the dissolution of silver iodide:
01:17Precipitation and Co-precipitation
Precipitation and coprecipitation methods can be used to separate a mixture of ions in a solution. In qualitative inorganic analysis, ions that form sparingly soluble precipitates with the same reagent are separated based on the differences in solubility products. For example, consider the separation of Cu(II) and Fe(II) ions by precipitation as insoluble sulfides. First, copper(II) sulfide is precipitated by the addition of acidic H2S, where the dissociation of H2S is suppressed. Adding H2S...
04:08Determining the pH of Salt Solutions
The pH of a salt solution is determined by its component anions and cations. Salts that contain pH-neutral anions and the hydronium ion-producing cations form a solution with a pH less than 7. For example, in ammonium nitrate (NH4NO3) solution, NO3− ions do not react with water whereas NH4+ ions produce the hydronium ions resulting in the acidic solution. In contrast, salts that contain pH-neutral cations and the hydroxide ion-producing anions form a solution with a pH greater than 7. For...
01:19Ionic Strength: Effects on Chemical Equilibria
The addition of an inert ionic compound increases the solubility of a sparingly soluble salt. For example, adding potassium nitrate to a saturated solution of calcium sulfate significantly enhances the solubility of calcium sulfate. Le Châtelier's principle cannot predict this shift in the equilibrium. Instead, this could be explained in terms of changes in the effective concentration of the ions in solution in the presence of added inert salt.
In this solution, the primary cation—the calcium...
In this solution, the primary cation—the calcium...