Samples of the edible mushroom Laccaria amethystina, which is known to accumulate arsenic, were collected from two uncontaminated beech forests and an arsenic-contaminated one in Denmark.
The total arsenic concentration was 23 and 77 mug As g-1 (dry weight) in the two uncontaminated samples and 1420 mug As g-1 in the contaminated sample.
The arsenic species were liberated from the samples using focused microwave-assisted extraction, and were separated and detected by anion-and cation-exchange high-performance liquid chromatography with an inductively coupled plasma mass spectrometer as arsenic-selective detector.
Dimethylarsinic acid accounted for 68-74%, methylarsonic acid for 03-2.9%, trimethylarsine oxide for 0.6-2.0% and arsenic acid for 0.1-6.1% of the total arsenic.
The unextractable fraction of arsenic ranged between 15 and 32%. The results also showed that when growing in the highly arsenate-contaminated soil (500-800 mug Asg-1) the mushrooms or their associated bacteria were able to biosynthesize dimethylarsinic acid from arsinic acid in the soil.
Furthermore, arsenobetaine and trimethylarsine oxide were detected for the first time in Laccaria amethystina.
Additionally, unidentified arsenic species were detected in the mushroom.
The finding of arsenobetaine and trimethylarsine oxide in low amounts in the mushrooms showed that synthesis of this arsenical in nature is not restricted to marine biota. (...)
Mots-clés Pascal : Contamination chimique, Pollution sol, Danemark, Europe, Produit alimentaire, Champignon comestible, Fungi, Thallophyta, Analyse chimique, Chromatographie HPLC, Méthode couplée, Spectrométrie ICP, Spectrométrie masse, Analyse quantitative, Arsenic Composé organique, Arsine tertiaire oxyde, Spéciation, Evaluation, Risque, Toxicité, DNA, Laccaria amethystina, Arsénobétaïne, Arsinique acide(diméthyl)
Mots-clés Pascal anglais : Chemical contamination, Soil pollution, Denmark, Europe, Foodstuff, Edible fungi, Fungi, Thallophyta, Chemical analysis, HPLC chromatography, Coupled method, Inductive coupling plasma spectrometry, Mass spectrometry, Quantitative analysis, Arsenic Organic compounds, Tertiary arsine oxide, Speciation, Evaluation, Risk, Toxicity, DNA
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 98-0223756
Code Inist : 002A35B09. Création : 11/09/1998.