Lead isotope ratios as tool for elucidation of chemical environment in a system of Macrolepiota procera (Scop.) Singer - soil

Abstract

The analysis of isotope ratios of lead in the mushrooms and soil, where they were grown, assisted with a principal component analysis, offered a new perspective for understanding possible chemical environment in a real setup of those compartments. The content of lead and its isotope compositions were determined in soil samples and mushroom Macrolepiota procera from unpolluted area of Mountain Goč, Serbia. Sequential extraction procedure based on the Commission of the European Community Bureau of Reference (BCR) was applied on soil samples in order to determine the distribution of lead in the labile and un-labile fractions of the soil. Caps and stipes of mushrooms were subjected to microwave acid-assisted digestion prior to measurements by inductively coupled plasma quadrupole mass spectrometer for determination of lead content and lead isotope ratios. Information about the chemical fractionation of Pb in soil, Pb isotopic data from soil fractions and fruiting bodies allowed a more detailed insight on the uptake mechanisms. Lead was predominantly associated with reducible fraction (~60%). Only its small portion (∼ 1%) was present in the exchangeable and acid-extractable fractions suggesting the low mobility of Pb. Lead isotope analysis revealed the presence of anthropogenic lead in the surface soil. Significant lower 206 Pb/ 207 Pb compared with other fractions was found in exchangeable and acid-soluble fraction (1.331 ± 0.010), which corresponds to the isotope ratio of European gasoline. The highest 206 Pb/ 207 Pb ratio was observed in reducible fraction (1.162 ± 0.007), while in oxidizable and residual fraction, those values were similar (1.159 ± 0.006 and 1.159 ± 0.004, respectively). Distinction of exchangeable and acid-extractable fractions from others was also confirmed, for the first time, by principal component analysis. The analysis of four isotope ratios ( 206 Pb/ 207 Pb, 208 Pb/ 206 Pb, 206 Pb/ 204 Pb, and 207 Pb/ 204 Pb) indicated that the analyzed M. procera accumulates lead from the first two fractions of topsoil layers.

Is a Lead Isotope Ratios in Wine Good Marker for Origin Assessment?

“…Accordingly, ICP-QMS has not the same sensitivity for different masses, due to differences in ion transmission and detection ( Devulder et al, 2013 ). This phenomenon causes a difference between the true values and the obtained LIRs data ( Đurđić et al, 2020 ; Marguí et al, 2007 ). Therefore, it is mandatory to correct the instrumental LIRs data on the mass-bias effect in order to improve accuracy in LIRs measurements.…”

“…Also, for the correction of instrumental LIRs data, it is necessary to calculate the bias factor ( K ). For calculation of K , a linear, potential or exponential algorithm can be used ( Đurđić et al, 2020 ; Marguí et al, 2007 ). In Table 1 , the values of LIRs of the certified reference material NIST SRM 981 were compared with LIRs instrumental data after their correction to the mass-bias effect, using external and internal standardization with potential algorithm ( Đurđić et al, 2020 ).…”

“…Lead isotopic composition, based on different ratios of stable isotopes ( 206 Pb/ 207 Pb, 208 Pb/ 206 Pb, 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 Pb), serves as a “ fingerprint ” for definition of different lead sources in the environment ( Erel et al, 1997 ; Larcher et al, 2003 ; Komárek et al, 2008 ; Đurđić et al, 2020 ). Analysis of the lead isotope ratios (LIRs) in food and beverages has provided a powerful tool for determining the geographical origin and authenticity, most often, of wine ( Medina et al, 2000 ; Tian et al, 2000 ; Barbaste et al, 2001 ; Mihaljevič et al, 2006 ; Bora et al, 2018 ; Epova et al, 2020 ).…”

“…Analysis of the lead isotope ratios (LIRs) in food and beverages has provided a powerful tool for determining the geographical origin and authenticity, most often, of wine ( Medina et al, 2000 ; Tian et al, 2000 ; Barbaste et al, 2001 ; Mihaljevič et al, 2006 ; Bora et al, 2018 ; Epova et al, 2020 ). In addition, LIRs can be used as a tool for elucidation of chemical environment in a mushrooms-soil system ( Đurđić et al, 2020 ).…”

“…On the other side, lead in wines can also be found as a result of human activities. Anthropogenic lead in wines mainly originates from traffic, fertilizer, pesticide treatment, as well as from metallurgical and smelting activities ( Almeida and Vasconcelos, 1999 ; Đurđić et al, 2020 ). LIRs might provide information on the origin of the wine assuming that sources of contamination do not distort the original isotope ratio pattern present in the local environment ( Tian et al, 2000 ).…”