Chemical dataset of levels of heavy metals in vineyard soil and grapevine leaf samples from Cape Winelands, South Africa.

The chemical analysis of vineyards is an essential tool for the early detection of risks, such as excessive fertilization and heavy metal and pesticide contamination in farm management. Soil and plant samples were collected in summer and winter from six different vineyards with varying agricultural practices in the Cape Winelands of the Western Cape Province, South Africa. The samples were pretreated in a microwave using CEM MARS 6™ Microwave Digestion and Extraction System (CEM Corporation, Matthews, NC, USA). Chemical element data were obtained using an inductively coupled plasma optical emission spectrometer (ICP-OES) (ICP Expert II, Agilent Technologies 720 ICP-OES). The data will be valuable for selecting and improving farming practices and gaining insights into the influence of seasonal variation and agricultural practices on the elemental accumulation in farmlands.

Levels of Heavy Metals in Grapevine Soil and Leaf Samples in Response to Seasonal Change and Farming Practice in the Cape Winelands.

Heavy metal toxicity is a major threat to the health of both humans and ecosystems. Toxic levels of heavy metals in food crops, such as grapes, can have devastating effects on plant health and the market value of the produce. Two important factors that may influence the prevalence of heavy metals in grapevines are seasonal change and farming practices. The objectives of this study were (i) to conduct a detailed pioneer screening of heavy metal levels in soils and grapevine leaf tissues in selected wine farms and (ii) to study the influence of season and farming on heavy metal levels in soils and grapevine leaf tissues. Soil and grapevine leaf samples were collected from demarcated areas in selected vineyards in the Cape Winelands region of South Africa. The sampling was conducted in winter and summer from the same sites. The soil and leaf samples were analysed using inductively coupled plasma mass spectrometry (ICP-MS) techniques. The pooled data from the farms practising conventional or organic farming showed that seasonal variation had no significant effect (DF = 1, 22; p > 0.05) on the heavy metal contents in the soil. When the soil data from the winter and summer months were compared separately or pooled, the influence of agricultural practice was well-pronounced in As (DF = 1, 22, or 46; p < 0.05) and Cu (DF = 1, 22, or 46; p <0.05). The agricultural practice greatly influenced (DF = 1, 22; p< 0.05) Cu, As, Cr, and Hg uptake, with little effect on Ni, Co, Cd, and Hg leaf contents. Generally, the heavy metals studied (Cr, Co, Ni, Zn, As, Cd, Hg, and Pb) were substantially below the maximum permitted levels in plant and soil samples, per the recommendations of the WHO and Er indices, respectively. However, moderate contamination of the soils was recorded for Cr, Ni, Zn, and Pb. Remarkably, the Cu levels in the organic vineyard soils were significantly higher than in the conventional vineyards. Furthermore, based on the Igeo index, Cu occurred at moderate to heavy contamination levels.