Related Experiment Video
Updated: Jun 28, 2026
08:01
Removal of Arsenic Using a Cationic Polymer Gel Impregnated with Iron Hydroxide
Published on: June 28, 2019
Extraction of arsenic compounds from lichens
Tanja Mrak1, Zdenka Slejkovec, Zvonka Jeran
1Department of Environmental Sciences, Jozef Stefan Institute, Jamova 39, Ljubljana, Slovenia. tanja.mrak@ijs.si
Talanta
|October 31, 2008
Summary
Optimizing arsenic extraction from lichens is crucial for environmental monitoring. A sequential soil extraction method significantly improved arsenic recovery from Hypogymnia physodes and Cladonia rei, identifying various arsenic compounds.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Biogeochemistry
Background:
- Lichens are sensitive bioindicators of environmental contamination, particularly for heavy metals like arsenic.
- Understanding arsenic speciation in lichens is vital for accurate ecological risk assessment.
- Previous extraction methods showed limited efficiency for arsenic compounds in lichen matrices.
Purpose of the Study:
- To evaluate and enhance extraction efficiency of arsenic compounds from two lichen species.
- To identify and quantify different arsenic species present in the extracted samples.
- To investigate the effectiveness of a sequential soil extraction procedure for lichen analysis.
Main Methods:
- Applied various extraction solvents (water, methanol/water, Tris buffer, acetone) at different temperatures.
- Utilized a sequential extraction procedure adapted from soil analysis protocols.
- Employed High-Performance Liquid Chromatography with Ultraviolet detection and Hydride Generation Atomic Fluorescence Spectrometry (HPLC-UV-HGAFS) for speciation.
Main Results:
- A sequential extraction procedure significantly increased arsenic recovery (45% for H. physodes, 83% for C. rei) compared to single solvent methods (<23%).
- Identified multiple arsenic compounds including arsenous acid, arsenic acid, and organoarsenic species in both lichen species.
- The lipid-soluble arsenic fraction was found to be negligible.
Conclusions:
- Sequential extraction protocols designed for soils are effective for improving arsenic recovery from lichens.
- A diverse range of arsenic compounds can be found in lichens from contaminated environments.
- Further research into lichen-specific extraction methods may yield even higher recovery rates.
Related Concept Videos
00:56Extraction: Advanced Methods
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is formed in...
01:27Microbial Leaching
Microbial leaching, also known as bioleaching, is an environmentally favorable method for extracting metals from low-grade ores using specific microorganisms. This biotechnological approach is particularly valuable for mining operations targeting copper, gold, and uranium, where traditional extraction methods may be economically or environmentally impractical.Copper Leaching and Microbial CatalysisIn copper bioleaching, crushed ore is arranged into heaps and irrigated with a dilute sulfuric...
01:08Sample Preparation for Analysis: Advanced Techniques
Accurate analysis of complex samples often requires advanced preparation techniques to achieve reliable and reproducible results. Samples containing inorganic or organic materials can be challenging to dissolve or decompose effectively. Standard sample preparation methods include acid digestion, fusion, dry ashing, and wet digestion.
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
Acid digestion with strong acids is commonly used to dissolve inorganic materials that are insoluble (do not dissolve) in water. This method can be useful for...
01:19Acid Mine Drainage
Mining activities that disturb sulfide-rich rocks, particularly those containing pyrite (FeS₂), initiate a cascade of geochemical and microbiological processes with serious environmental implications. When exposed to air and water, pyrite undergoes oxidation, releasing sulfate, ultimately forming sulfuric acid and mobilizing heavy metals into surrounding water systems. This phenomenon, known as acid mine drainage (AMD), results in low pH waters laden with toxic elements that threaten aquatic...
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...