Accumulation patterns and health risk assessment of potentially toxic elements in the topsoil of two sloping vineyards (Tokaj-Hegyalja, Hungary)

Abstract

Purpose In agricultural soils, accumulation and bioavailability patterns of potentially toxic elements (PTEs) are key ecological and health risk issues, especially in metal-based crop protection systems such as those applied in vineyards. However, PTE levels in the topsoils of historical wine-growing regions of Hungary have been scarcely studied so far. The specific goals of this research were to assess the accumulation tendencies and bioavailability of PTEs complemented with human health risk assessment in two sloping vineyards with pH-contrasted soils in Tokaj-Hegyalja, Hungary, and under different farming practices. Methods Composite topsoil (< 20 cm) and borehole samples were collected from two vineyards and local forests. The total and bioavailable PTE contents (Zn, Pb, Co, Ni, Cr, Cu) were analyzed following digestion in aqua regia and extraction with a strong chelating agent (0.05 M Na2-EDTA). Enrichment factors (EFs) were calculated based on Fe as a reference element and the local uncultivated soil. The hazard indexes (HIs) for outdoor workers, children, and adults living in residential areas near the vineyards were calculated to assess the health risks associated with the target PTEs. Results Higher PTE contents were observed in the organic vineyard (near Tokaj) compared to the conventional one (near Tállya), except for Cu and Pb. The EFs confirmed that the duration of Cu-fungicide applications mainly determines the soil-bound Cu levels, with an average of 2.6 in the 28-year-old organic vineyard and 9.6 in the more than 100-year-old conventional vineyard. The PTEs predominantly accumulated at the top of the hillslope in Tállya, while in Tokaj, a general trend of downslope accumulation of PTEs can be noticed. Bioavailable Cu reached a maximum of 50% of total Cu at the top of the hillslope (Tállya) and positively correlated with soil organic matter content. Iron/Mn oxides, total Ca content, and soil pH show a significant correlation with the PTE total contents (other than Cu); meanwhile, their bioavailability is mainly influenced by Mn oxides. The calculated HIs are less than 1, indicating no elevated health risk. Total Cr is the major contributor to the HI in both vineyards, reaching 79.0% (Tokaj) and 49.7% (Tállya). Conclusion Overall, the accumulated Cu contents mainly depended on the vineyard age, while farming practices and terrain morphology play a minor role in its spatial distribution. The further accumulation of PTEs, especially in high-metal hotspots within the vineyards, may ultimately cause toxicity to re-planted grapevines, soil biota, and, in the longer term, farmers and residents.

Spatial distribution and source apportionment of DTPA-extractable metals in soils surrounding the largest Serbian steel production plant

“…As soil properties such as soil texture, OM content, and pH may impact the distribution and bioavailability of PTEs in soil [ 21 , 41 , 42 ], their relationship with PTEs is analyzed in this study. The correlation matrix ( Table 3 ) was used to estimate the strength of the relationships among analyte pairs in the soil samples.…”

Quantification of Intra- vs. Inter-Row Leaching of Major Plant Nutrients in Sloping Vineyard Soils

“…Management includes the use of fertilizers and pesticides, tillage, and trafficking with subsequent subsoil compaction [19], because of which an extensive lateral preferential flow network can be formed on top of a compaction layer, e.g., the plough pan. Thus, nutrient loss at sloped vineyards frequently occurs, not only via leaching, but also via surface or subsurface runoff [20]. Cover crops can decrease erosion and surface runoff [21], and therefore minimize the transport of nutrients to the surrounding environment, with greater reduction of erosion confirmed for cover formed by grass than other plant species, such as legumes [22].…”

Risk Assessment and Limiting Soil Factors for Vine Production—Cu and Zn Contents in Vineyard Soils in Galicia (Rías Baixas D.O.)

“…Despite the necessary and beneficial use of fungicides in vineyards, their prolonged and uncontrolled use has led to an accumulation of Cu and also Zn in many vineyard soils. These elements have led to soil degradation and severe environmental problems in other ecosystem compartments [3,4].…”

“…Among these soil factors, it is necessary to highlight those related to soil characteristics (e.g., effective depth, stoniness, erosion risk associated with the slope, organic matter content, N and P contents, C/N ratio, effective cation exchange capacity, macronutrient (K, Mg, Ca) balance, pH, and/or salinity) [28,30]. Moreover, total metal contents, particularly Cu and Zn, are used as indicators to assess vineyard soil pollution associated with fungicides [4,31,32]. In any case, the total metal content is not usually a good indicator to assess pollution in vineyard soils.…”

“…In any case, the total metal content is not usually a good indicator to assess pollution in vineyard soils. Several studies have shown that to study the contamination and the possible toxicity, mobility, distribution, and/or transport of metals in vineyard soils, it is much better to determine the (bio)available metal content [4,[33][34][35].…”