Arsenic in soil and grapes and changes in elemental content during winemaking

Abstract

Healthiness is a prerequisite for all agricultural products, foods and beverages. The presence of arsenic (As) in these products creates concern, due to its carcinogenicity. In the case of vines grown on soils naturally rich in As, investigation of its content in grapes and the relative wines, as well as its possible effects on the winemaking process, may be appropriate.

28 different vineyards planted with Chardonnay in Trentino (north-eastern Italy) were studied. 10 of these were close to an ancient mining area with deposits of arsenopirite and other sulfide minerals containing As traces. Soil and grapes from each vineyard were analysed to determine As content. The content of aqua regia extractable As was measured in the soil samples using the ISO 11466/1995 method, whereas  As in grapes was determined after acid mineralisation in a closed vessel.

White wines were produced from 7 vineyards characterised by the highest As content using 10 yeast strains. Furthermore, the same grape samples were fermented with skin-contact during fermentation using only 1 yeast strain.

The content of As in the soil and grapes was higher in vineyards near the ancient mining area. Skin-contact increased As in wine and statistically significant differences were found among yeast strains. Nevertheless, in the conditions of this study, the content of As in wines was always below the limit (200 µg/L) suggested by the OIV, by at least 100 times.