Health Risk and Quality Assessment of Vegetables Cultivated on Soils from a Heavily Polluted Old Mining Area

Abstract

Three garden vegetables—radish, carrot and lettuce—were cultivated in a pot experiment using two soils from the Příbram area polluted mainly by cadmium (Cd), zinc (Zn), lead (Pb) and chromium (Cr). The soils of the Příbram district, Czech Republic, are heavily polluted as a result of the atmospheric deposition of toxic elements originating from historic lead–silver mining and smelting activities. The results showed that lettuce absorbed the highest amounts of toxic elements (Cd 28 and 30, Cr 12 and 13, Zn 92 and 205 mg·kg−1 DW), except Pb, which was higher in radish (30 and 49 mg·kg−1 DW). Changes in macronutrient contents in edible parts were not found, except for sulfur. A higher total free amino acids (fAAs) accumulation was shown in all vegetables in more contaminated soil, with the highest fAA content being in radish. A group of essential fAAs reached 7–24% of total fAAs in vegetables. The risk to human health was characterized using the target hazard quotient and total hazard index (HI). The cumulative effect of the consumption of vegetables with HI > 1 showed possible non-carcinogenic health effects for lettuce and carrot. HI decreased in the order Cd > Pb > Cr > Zn. The carcinogenic risk of toxic elements decreased in the order Cd > Cr > Pb (0.00054, 0.00026, 0.00003). These values showed a carcinogenic risk from the consumption of lettuce and carrot and confirmed that the adult population of the studied area is at high risk if lettuce and carrot cultivated in this area are consumed daily.

Multicontamination Toxicity Evaluation in the Model Plant Lactuca sativa L.

“…According to Zhu et al [61], N metabolism is central to the plant response to TEs, and its influence by TEs is related to the changes in free AA metabolism. Even though changes in AA metabolism in plants can vary widely due to the influence of TEs and the plant itself, several researchers have confirmed that AA increases in plant leaves and roots are caused by As, Cd, Pb, and Zn [3,[61][62][63][64][65][66][67][68]. Consistent with these results, the TEs of the multicontamination group induced an increase in total free AA content in lettuce leaves, while the content in the lettuce roots was not significantly affected.…”

“…Floodplain soils of the Litavka River (Příbram region, Czech Republic) are heavily multicontaminated by historic lead-silver mining and smelting activities and extreme flooding events that occurred at various time between 1932 and 2002 [1]. Analyses from this region have shown that the highest enrichment levels of soils are observed for Pb, Zn, Cd, and As [2,3]. The effect of soil multicontamination on plants is influenced by many factors, such as availability, mobility, and oxidation state of TEs in soil; interactions between elements; soil properties (pH, redox potential, texture, clay content, and soil organic matter); plant species and cultivars; and plant growth period [4][5][6].…”

“…Bioaccumulation of TEs in the edible parts of vegetables cultivated in contaminated soils results in their entry into the food chain and represents a potential health risk [3]. TE uptake by vegetables can be classified as follows according to the TE concentrations in their edible parts: leafy/stem vegetables > root vegetables > tubers > fruiting vegetables/fruits/berries.…”

Response of Carrot (Daucus carota L.) to Multi-Contaminated Soil from Historic Mining and Smelting Activities

“…In this study, a decline in the total content of free AAs was observed in the roots, but this was not a statistically significant difference between the variants (Table 3). Similarly, the decrease in free AA content was confirmed in edible parts of carrot, radish and lettuce growing on strong multi-contaminated soil [86]. Zhu et al [87] observed a significant decrease in AAs in the roots of Crassocephalum crepidioides caused by Cd applied to soil.…”

“…The Cd, Pb and Zn content was determined according to Pavlíková et al [86]. Briefly, homogenised dry material (0.5 ± 0.05 g) was digested in 10 mL of a mixture of HNO 3 and H 2 O 2 (4:1, v/v) in an Ethos 1 device (MLS GmbH, Leutkirch im Allgäu, Germany).…”