Influence of the soil pH in the uptake and bioaccumulation of heavy metals (Fe, Zn, Cu, Pb and Mn) and other elements (Ca, K, Al, Sr and Ba) in vine leaves, Castilla-La Mancha (Spain)

Each soil-plant system has specific parameters on the uptake of different minerals in the soil, depending on several factors. One of these factors, perhaps the most important, is the pH. The aim of the work described here was to ascertain the role of pH in the uptake of some mineral elements, including heavy metals. For this purpose, 101 vineyard plots have been selected in Castilla-La Mancha (Spain) and soils and leaf samples have been analysed by the XRF technique. The BAC (biological absorption coefficient) was also calculated. The behaviour observed for some of the studied elements was different in acidic and alkaline soils: Copper (Cu) and calcium (Ca) had high BAC values in alkaline soils (1.87 and 0.99, respectively) and in acidic soils (4.67 for Ca and 2.24 for Cu); in alkaline soils iron (Fe) and aluminium (Al) had the same BAC value (0.02). Barium (Ba) and lead (Pb) showed similar values in both cases (0.20 in acidic soil and 0.26 in alkaline soil for Ba; 0.15 in acidic soil and 0.29 in alkaline soil for Pb). In contrast, strontium (Sr), zinc (Zn) and manganese (Mn) were preferentially bioaccumulated in acidic soils (1.01, 1.00 and 0.50 respectively). Mineral elements are accumulated in the leaves of vines depending on the soil pH. The pH influences the ionic form in which the element is present in the soil.