Validation of an Electrothermal Atomization Atomic Absorption Spectrometry Method for Quantification of Total Chromium and Chromium(VI) in Wild Mushrooms and Underlying Soils

Abstract

An ETAAS method was validated to quantify total Cr and Cr VI in mushrooms and the underlying soils. The method includes a sample pretreatment for total Cr dissolution using a wet acid digestion procedure and a selective alkaline extraction for Cr VI . The limits of detection were, expressed in µg/L, 0.15 and 0.17 for total Cr and Cr VI , respectively. The linearity ranges under the optimized conditions were 0.15-25.0 and 0.17-20.0 µg/L for total Cr and Cr VI , respectively. The limits of quantification were, expressed in µg/g of dry weight, 0.0163 and 0.0085 for total and hexavalent chromium, respectively. The precision of the instrumental method for total Cr and Cr VI was lower than 1.6%, and for the analytical method, it was lower than 10%. The accuracy of the method for Cr VI quantification was evaluated by the standard additions method, with the recoveries being higher than 90% for all of the added concentrations. For total Cr, certified reference materials (lichen CRM 482 and soil sample NCS ZC73001) were used. An interference study was also carried out in a mushroom simulated matrix, and it was verified that the deviations of the expected values were lower than 4.0% for both total Cr and Cr VI . The validated method was applied to the evaluation of total Cr and Cr VI in 34 wild mushrooms and 34 respective underlying soil samples collected in two different regions of Portugal (Beira Interior and Trá s-os-Montes), with different locations regarded as noncontaminated or contaminated areas. The species were identified by a mycologist and subdivided into 10 genera and 15 species: Amanita (rubescens, muscaria, and ponderosa), Boletus (regius), Lactarius (deliciosus, vellereus, and piperatus), Suillus (granulatus and luteus), Tricholoma (acerbum), Agaricus (sylvicola), Volvariella (gloiocephala), Lecopaxillus (giganteus), Macrolepiota (procera), and Psilocybe (fascicularis). The mean values found for total Cr were 1.14 and 1.11 µg/g of dry weight, and for Cr VI , the mean values were 0.103 and 0.143 µg/g of dry weight for cap and stalk, respectively. For soils, the mean concentrations found were, for total Cr, 84.0 µg/g and, for Cr VI , 0.483 µg/g. The bioconcentration factors (BCFs) based on dry weight for cap and stalk were determined, and the values found, for both total Cr and Cr VI , were always <1, although for hexavalent chromium, the BCFs were 10 times higher than for total chromium. KEYWORDS: Mushroom; soil; total Cr; Cr VI ; atomic absorption spectrometry INTRODUCTIONHeavy metals are considered to be among the most pollutant agents in all of the environmental compartments. In the soils, heavy metals are derived from natural components or geological sources, as well as from anthropogenic activities. Apart from the occupational exposure, the human exposure to toxic metals is mainly through the diet, and the vegetable fraction is an important contribution for metal intake.Mushrooms constitute part of the human diet because they provide carbohydrates, proteins, vitamins, and minerals (1). Moreover, mushroom...

Cr(VI) speciation in foods by HPLC-ICP-MS: investigation of Cr(VI)/food interactions by size exclusion and Cr(VI) determination and stability by ion-exchange on-line separations

“…In the optimal experimental conditions, limits of detection (LOD) and limits of quantification (LOQ) were calculated according to IUPAC criteria as the concentration corresponding to three times and ten times the standard deviation of ten blank solutions, respectively. These detection limits, even if higher than those previously reported for Cr(VI) determination in foods [10][11][12][13][14], are, to our knowledge, the first ones obtained from an on-line speciation-based analytical protocol.…”

“…Soares et al [12] measured total Cr in an alkaline extract of bread, assuming that it was corresponding to Cr(VI) because of the expected precipitation of Cr(III) at this pH. Figueiredo et al did the same for wild mushrooms [13] and Panichev et al [14] for different plant samples. In these studies, Cr(VI) concentrations reported were up to 15 μg/kg.…”

Tolerance and Bioaccumulation of Copper by the Entomopathogen Beauveria bassiana (Bals.-Criv.) Vuill. Exposed to Various Copper-Based Fungicides

“…For the highest doses of fungicides (2RD), copper content in B. bassiana decreased. It is known that fungi are able to accumulate significant amounts of metals (Gadd 1993;Figueiredo et al 2007;Baptista et al 2009), including entomopathogenic fungi (Popowska-Nowak et al 2004;Fomina et al 2005b). Although B. bassiana was able to solubilize copperbased fungicides, and therefore increase copper bioavailability and toxicity, this strain has shown high tolerance to those fungicides, especially to copper hydroxide and copper oxychloride.…”

The Accumulation of Risk and Essential Elements in Edible Mushrooms Chlorophyllum rhacodes, Suillus grevillei, Imleria badia, and Xerocomellus chrysenteron Growing in the Czech Republic

“…Total Cr contents were determined after a microwave assisted digestion of the samples and determination of Cr VI was following the method described by Figueiredo et al [14] Total chromium contents in samples of Chlorophyllum rhacodes, Suillus grevillei, Imleria badia, and Xerocomellus chrysenteron were 0.08 � 0.03, 0.16 � 0.09, 0.09 � 0.07, and 0.17 � 0.16 mg kg À 1 DM, respectively. Total Cr contents were determined after a microwave assisted digestion of the samples and determination of Cr VI was following the method described by Figueiredo et al [14] Total chromium contents in samples of Chlorophyllum rhacodes, Suillus grevillei, Imleria badia, and Xerocomellus chrysenteron were 0.08 � 0.03, 0.16 � 0.09, 0.09 � 0.07, and 0.17 � 0.16 mg kg À 1 DM, respectively.…”

“…Sarikurkcu et al [6] reported that Lycoperdon perlatum collected from the South Aegean Region in Turkey exceeded legal limits for Pb (as well as for Fe, Mn, Cr, Ni, and Co). Toxic Cr VI contents were measured solely by Figueiredo et al [14] They reported mean contents of total chromium 1.14 and 1.11 mg kg À 1 DM in caps and stalks for 34 samples of 15 mushroom species and mean contents of hexavalent chromium 0.10 and 0.14 mg kg À 1 DM, respectively. [7] Zinc is another metal with high contents in edible mushroom fruiting bodies.…”