Lead contamination in Portuguese red wines from the Douro region: from the vineyard to the final product

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

Lead isotope ratio pattern (²⁰⁶Pb/²⁰⁷Pb, ²⁰⁸Pb/²⁰⁶Pb, ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb) was analyzed in 59 samples of Serbian wine, from four geographical regions. By utilization of powerful inductively coupled plasma mass spectrometry (ICP-QMS), lead isotope ratios were used as unique "fingerprint", when combined with multivariate methods of analysis (Principal Component Analysis), provided information on the geographical origin of wine. In validation of ICP- QMS method and quantitative analysis, the certified reference material NIST SRM 981 was employed to test the mass-bias correction and thallium isotopes ²⁰³Tl and ²⁰⁵Tl (NIST SRM 997) as an internal standard. The obtained results were discussed in correlation with the corresponding values of LIRs of different European and Australian wines. In addition, the impact of anthropogenic Pb from different sources on the total Pb isotopic composition in Serbian wines was analyzed too. On the other side, the obtained values of Pb content were compared with the applicable health safety standards, according to the International Code of Oenological Practices.

A Multidisciplinary Fingerprinting Approach for Authenticity and Geographical Traceability of Portuguese Wines

The interest in developing reliable wine authenticity schemes is a hot-topic, especially for wines with recognized added-value. In order to accomplish this goal, two dimensions need to be considered: the grapevine variety determination and the geographical provenance. The aim of this study was to develop a multidisciplinary approach applicable to wines from the sub region Melgaço and Monção of the demarcated Vinho Verde region and from the demarcated Douro region. The proposed scheme consists on the use of DNA-based assays to detect Single Nucleotide Polymorphisms (SNPs) on three genes of the anthocyanin pathway (UFGT, F3H and LDOX) coupled with High-resolution melting (HRM) analysis aiming the varietal identification. The Alvarinho wines revealed to have the same haplotype using this marker set, demonstrating its applicability for genetic identification. In addition, to assess their geographical provenance, a multi-elemental approach using Sr and Pb isotopic ratios of wine, soil and bedrock samples was used. The isotopic data suggest a relation between Sr and Pb uptake by vine roots and soil's texture and clay content, rather than with the whole rock's isotopic ratios, but also highlights the potential of a discriminating method based on the combination of selected isotopic signatures.

Distinguishing between Natural and Industrial Lead in Consumer Products and Other Environmental Matrices

California's Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) was designed to protect the state's populace from exposures to toxic levels of chemicals in consumer products, including foods, by requiring businesses to warn the public about any of those hazards. There is, however, one qualification in the legislation, which is that warnings are not required if the source of that contamination is natural, as opposed to industrial. That qualification is especially problematic for lead because "natural" and "industrial" lead have a common origin and behave the same in the environment and industrial lead contamination has been pandemic for millennia. As a result of that historic and ongoing contamination, ambient lead levels in the biosphere may be orders of magnitude above natural levels, limiting comparisons of "natural" versus "industrial" lead concentrations in products. Further complicating those comparisons are reports of erroneously high measurements of lead concentrations in the biosphere as a result of sample contamination during collection, storage, and analysis. Some of those problems may be addressed with measurements of lead concentrations using rigorous trace metal clean techniques. These techniques often yield lead concentrations that are below the Act's maximum exposure in foods and non-foods of 0.5 μg/day, eliminating the need for a public alert. Those techniques have also been used to derive natural lead concentrations in a few organisms (marine fish, humans, rats, and dandelions), which range from 2- to 100-fold below ambient levels. However, extrapolating from those few determinations to establish natural lead levels in other organisms is complicated and often inappropriate. Complementary stable lead isotopic composition measurements have also been used to estimate the percent of natural and industrial lead in some consumer products, including foods, wine, and dietary supplements. These measurements, however, require the isotopic compositions of both the "natural" and "industrial" lead end members, which may be poorly defined. In addition, the global market has further complicated identification of the "industrial" lead end member, because lead contamination of foods can occur during production, harvesting, storage, shipping, processing, and packaging, which can happen in different locales within a country, different countries, and even different continents.

Processing Aids in Food and Beverage Manufacturing: Potential Source of Elemental and Trace Metal Contaminants

There are currently increased efforts to determine potential sources of trace metal contaminants in the food supply. While there are likely many sources of these elements, processing of foods has gained attention as one such route. Research is reviewed on how processing aids used for food production, including beverage filtration and fining, have been targeted as potential sources of trace metals. Potential remediation methods to reduce elemental transfer occurring during processing is discussed. While food processing aids are often a critical part of food manufacturing, they can be a potential source of trace metal contaminants, including heavy metals.

Use of Lead Isotopic Ratios as Geographical Tracer for Lambrusco PDO Wines

In this study, the lead isotope signature was tested with the aim to verify its potential as geographic tracer for wine production and particularly for the Lambrusco PDO wines of the province of Modena (Italy). A solid phase extraction procedure, for separating lead from the investigated matrices, soil and wine, was optimized. Furthermore, different mathematical models, based on an exponential law and internal or external correction approach, were evaluated for the correction of instrumental mass dependent fractionation. The optimized analytical procedure yielded isotopic ratio data relative to the lead NIST 981 standard, ²⁰⁸Pb/²⁰⁶Pb = 2.16664 and ²⁰⁷Pb/²⁰⁶Pb = 0.914645, in good agreement both with the tabulated values and with the most recent literature data. Measured isotope ratio data highlight the contribute of multiple lead sources in bottled wine but different from the one present in soils.

High-Precision In Situ 87Sr/86Sr Analyses through Microsampling on Solid Samples: Applications to Earth and Life Sciences

An analytical protocol for high-precision, in situ microscale isotopic investigations is presented here, which combines the use of a high-performing mechanical microsampling device and high-precision TIMS measurements on micro-Sr samples, allowing for excellent results both in accuracy and precision. The present paper is a detailed methodological description of the whole analytical procedure from sampling to elemental purification and Sr-isotope measurements. The method offers the potential to attain isotope data at the microscale on a wide range of solid materials with the use of minimally invasive sampling. In addition, we present three significant case studies for geological and life sciences, as examples of the various applications of microscale ⁸⁷Sr/⁸⁶Sr isotope ratios, concerning (i) the pre-eruptive mechanisms triggering recent eruptions at Nisyros volcano (Greece), (ii) the dynamics involved with the initial magma ascent during Eyjafjallajökull volcano's (Iceland) 2010 eruption, which are usually related to the precursory signals of the eruption, and (iii) the environmental context of a MIS 3 cave bear, Ursus spelaeus. The studied cases show the robustness of the methods, which can be also be applied in other areas, such as cultural heritage, archaeology, petrology, and forensic sciences.

Trace metals transfer during vine cultivation and winemaking processes

BACKGROUND

The study was focused on Zn, Cu and Pb transfer in the system of soil-grape-must-juice-wine in a Chardonnay grape variety from Ukrainian vine growing regions. The analyses of soil, grape, must, pomace, juice and wine were done at the study plot in the south-west of Crimea.

RESULTS

Commercial white wines of Chardonnay from different vine growing regions in Ukraine were analysed for trace metals content. Results revealed that trace elements transfer was related to diverse Zn, Cu and Pb sources, trace metals bioavailability, their speciation and complexes during the wine making processes. The analysed commercial wines had lower Cu, Zn and Pb concentrations than wine from the Inkerman study plot.

CONCLUSION

Trace metals concentrations were comparable to those in European wines and lower than limits recommended by International Organization of Vine and Wine. The tentative relationship between wine and soil was found for Zn at the study plot. The method can be used to describe the relationship between the soil and wine in other study areas. © 2017 Society of Chemical Industry.

Tracing changes in atmospheric sources of lead contamination using lead isotopic compositions in Australian red wine

Air quality data detailing changes to atmospheric composition from Australia's leaded petrol consumption is spatially and temporally limited. In order to address this data gap, wine was investigated as a potential proxy for atmospheric lead conditions. Wine spanning sixty years was collected from two wine regions proximal to the South Australian capital city, Adelaide, and analysed for lead concentration and lead and strontium isotopic composition for source apportionment. Maximum wine lead concentrations (328 μg/L) occur prior to the lead-in-air monitoring in South Australia in the later 1970s. Wine lead concentrations mirror available lead-in-air measurements and show a declining trend reflecting parallel reductions in leaded petrol emissions. Lead from petrol dominated the lead in wine ((206)Pb/(207)Pb: 1.086; (208)Pb/(207)Pb: 2.360) until the introduction of unleaded petrol, which resulted in a shift in the wine lead isotopic composition closer to vineyard soil ((206)Pb/(207)Pb: 1.137; (208)Pb/(207)Pb: 2.421). Current mining activities or vinification processes appear to have no impact with recent wine samples containing less than 4 μg/L of lead. This study demonstrates wine can be used to chronicle changes in environmental lead emissions and is an effective proxy for atmospherically sourced depositions of lead in the absence of air quality data.

Correlating wine quality indicators to chemical and sensory measurements

Twenty-seven commercial Californian Cabernet Sauvignon wines of different quality categories were analyzed with sensory and chemical methods. Correlations between five quality proxies-points awarded during a wine competition, wine expert scores, retail price, vintage, and wine region-were correlated to sensory attributes, volatile compounds, and elemental composition. Wine quality is a multi-faceted construct, incorporating many different layers. Depending on the quality proxy studied, significant correlations between quality and attributes, volatiles and elements were found, some of them previously reported in the literature.

The combined impact of vineyard origin and processing winery on the elemental profile of red wines

The combined effects of vineyard origin and winery processing have been studied in 65 red wines samples. Grapes originating from five different vineyards within 40 miles of each other were processed in at least two different wineries. Sixty-three different elements were determined with inductively coupled-plasma mass spectrometry (ICP-MS), and wines were classified according to vineyard origin, processing winery, and the combination of both factors. Vineyard origin as well as winery processing have an impact on the elemental composition of wine, but each winery and each vineyard change the composition to a different degree. For some vineyards, wines showed a characteristic elemental pattern, independent of the processing winery, but the same was found for some wineries, with similar elemental pattern for all grapes processed in these wineries, independent of the vineyard origin. Studying the combined effects of grapegrowing and winemaking provides insight into the determination of geographical origin of red wines.

Detection of copper, lead, cadmium and iron in wine using electronic tongue sensor system

An array of 10 potentiometric chemical sensors has been applied to the detection of total Fe, Cu, Pb and Cd content in digested wine. As digestion of organic matter of wine is necessary prior to the trace metal detection using potentiometric sensors, sample preparation procedures have been optimized. Different variants of wet and microwave digestion and dry ashing, 14 conditions in total, have been tested. Decomposition of organic matter was assessed using Fourier transform mid-infrared spectroscopy and total phenolic content. Dry ashing was found to be the most effective method of wine digestion. Measurements with sensors in individual solutions of Fe(III), Cu(II), Pb(II) and Cd(II) prepared on different backgrounds have shown that their detection limits were below typical concentration levels of these metals in wines and, in the case of Cu, Pb and Cd below maximum allowed concentrations. Detection of Fe in digested wine samples was possible using discrete iron-sensitive sensors with chalcogenide glass membranes with RMSEP of 0.05 mmol L(-1) in the concentration range from 0.0786 to 0.472 mmol L(-1). Low concentration levels of Cu, Pb and Cd in wine and cross-sensitivity of respective sensors resulted in the non-linearity of their responses, requiring back-propagation neural network for the calibration. Calibration models have been calculated using measurements in the model mixed solutions containing all three metals and a set of digested wine sample. RMSEP values for Cu, Pb and Cd were 3.9, 39 and 1.2 μmol L(-1) in model solutions and 2, 150 and 1 μmol L(-1) in digested wine samples.

Lead isotopes reveal different sources of lead in balsamic and other vinegars

Fifty-eight brands of balsamic vinegars were analyzed for lead concentrations and isotopic compositions ((204)Pb, (206)Pb, (207)Pb, and (208)Pb) to test the findings of a previous study indicating relatively high levels of lead contamination in some of those vinegars--more than two thirds (70%) of them exceeded California's State Maximum Level (34 μg/L) based on consumption rates ≥0.5 μg Pb per day. The lead isotopic fingerprints of all those vinegars with high lead concentrations were then found to be primarily anthropogenic. This isotopic analysis unquestionably reveals multiple contamination sources including atmospheric pollutant Pb and an unidentified contamination source, likely occurring after grape harvest. Organically grown grape vinegars display the same Pb content and isotopic signatures as other vinegars. This implies that pesticides might not be a significant source of pollutant Pb in vinegars. A significant post-harvest contamination would be inherited from chemicals added during production and/or material used during transport, processing or storage of these vinegars. This is consistent with the highest Pb levels being found in aged vinegars (112±112 μg/L) in contrast to other vinegars (41.6±28.9 μg/L) suggesting contamination during storage. It is, therefore, projected that lead levels in most vinegars, especially aged balsamic and wine vinegars, will decrease with improvements in their manufacture and storage processes consequential to recent concerns of elevated levels of lead in some vinegars.

Identification of Marchfeld asparagus using Sr isotope ratio measurements by MC-ICP-MS

This work focuses on testing and application of Sr isotope signatures for the fast and reliable authentication and traceability of Asparagus officinalis originating from Marchfeld, Austria, using multicollector inductively coupled plasma mass spectrometry after optimised Rb/Sr separation. The major sample pool comprises freeze-dried and microwave-digested asparagus samples from Hungary and Slovakia which are compared with Austrian asparagus originating from the Marchfeld region, which is a protected geographical indication. Additional samples from Peru, The Netherlands and Germany were limited in number and allowed therefore only restricted statistical evaluation. Asparagus samples from Marchfeld were harvested within two subsequent years in order to investigate the annual variation. The results show that the Sr isotope ratio is consistent within these 2 years of investigation. Moreover, the Sr isotope ratio of total Sr in soil was found to be significantly higher than in an NH4NO3 extract, reflecting the mobile (bioavailable) phase. The isotope composition in the latter extract corresponds well to the range found in the asparagus samples in Marchfeld, even though the concentration of Sr in asparagus shows no direct correlation to the concentration of Sr in the mobile phase of the soil. The major question was whether the 'Marchfelder Spargel' can be distinguished from samples from the neighbouring countries of Hungary and Slovakia. According to our findings, they can be clearly (100%) singled out from the Hungarian samples and can be distinguished from the Slovakian asparagus samples with a probability of more than 80%.

Cadmium, lead and phytochemicals

Some metals are essential, others are found as contaminants in foodstuffs. There is some doubt on the antioxidant nature of foods or beverages containing phytochemicals because of cadmium and lead in foods. Evidence from epidemiological and experimental data has found an association between high fruit and vegetable intake and low cancer risk. However, these foods may also contain high amounts of carcinogenic metals, e.g., cadmium and lead shown to interfere with the repair of DNA damage. In this context, healthy and harmful effects of some nutrients are debated. As the benefits of a diet rich in fruits and vegetables are emphasized, attempts for regular mass administration of single food should be done prudently.

Determination of lead and cadmium in wines by graphite furnace atomic absorption spectrometry

The lead (Pb) and cadmium (Cd) content of various wines on the Korean market were determined by graphite furnace atomic absorption spectrometry using Zeeman background correction and peak area mode. All wine samples were microwave-digested in concentrated HNO(3). Ammonium dihydrogen phosphate and magnesium nitrate were used as matrix modifiers for both Pb and Cd analyses. The mean Pb content of the wines was about 29 microg l(-1) ranging from 5 to 87 microg l(-1). Also, the means of Cd were about 0.5 microg l(-1) ranging from < 0.1 to 3.0 microg l(-1). The mean recoveries of Pb and Cd were 92.8 and 101.3% and their analytical detection limits were 1.0 and 0.1 microg l(-1), respectively. Sixty brands of wine were classified into red and white, but no statistically significant difference in Pb and Cd content was observed.