## 3 Results and Discussion
### The Bioaccumulation of Elements in Crops  
The Bioconcentration Factors (BFs) of soil heavy metals in crop plant leaves and caryopsis/achenes are shown in Figures 12 and 13.  
Figure 12: Bioaccumulation factor of heavy metals in wheat and corn leaves and caryopsis.  
The results indicate that, in the agroecological conditions of the studied area, _wheat_ plants tend to exclude the bioaccumulation of Cd, Co, Cr, Ni, and Pb in their tissues. BFs for Cd ranged from 0.01 to 0.38 for leaves and from 0.0013 to 0.43 for caryopsis. BFs for Co were between 0.005 and 0.06 for leaves and from 0.0016 to 0.01 for caryopsis. The lowest BFs were observed for Cr (0.0024-0.03 for leaves and 0.0005-0.001 for caryopsis). BFs for Ni ranged between 0.02 and 0.12 for leaves and from 0.01 to 0.04 for caryopsis. BFs for Pb ranged from 0.05 to 0.10 for leaves and from 0.0017 to 0.14 for caryopsis. In contrast, for Zn and Cu, the bioaccumulation pattern was different. While the trend for the other elements was leaves > caryopsis, for Zn and Cu, it was to 0.14 for caryopsis. In contrast, for Zn and Cu, the bioaccumulation pattern was different. While the trend for the other elements was leaves > caryopsis, for Zn and Cu, it was caryopsis > leaves. BFs for Zn ranged from 0.43 to 0.62 for leaves and from 0.54 to 0.72 for caryopsis. The bioaccumulation of Cu was particularly pronounced in caryopsis, with BFs ranging from 0.23 to 1.09 for leaves and from 0.33 to 2.44 for caryopsis.  
In the case of corn leaves and caryopses, the bioaccumulation factor for most elements was below one (the bioaccumulation threshold--B.Tresh.), indicating a limited capacity for phytoaccumulation under the ecological conditions in which the corn was grown. However, exceptions were observed for Cd, Zn, and Cu, with BFs exceeding one, suggesting a tendency for bioaccumulation of these elements in the leaves. Comparing the sections of the corn plant, the overall order of bioaccumulation was from leaf to caryopsis. Specifically, the BFs in leaves followed the order Cd (0.64-1.67) > Zn (1.00-1.23) > Cu (1.02-1.30) > Pb (0.16-0.41) > Ni (0.02-0.03) > Cr (0.0228-0.0229) > Co (0.005-0.009), while in caryopses, it was Zn (0.31-0.32) > Cd (0.03-0.21) > Cu (0.07-0.15) > Ni (0.0026-0.02) > Cr (0.0023-0.0052) > Co (0.0006-0.0010).  
The results for sunflower BFs indicate that the bioconcentration of Cu, Cd, and Zn in both the leaves and achenes (seeds) is higher than that of other elements. The highest bioaccumulation values are observed for Cu, which in sampling sites S-2, V-2, and V-3 show the most significant accumulation. Specifically, for leaves, the bioaccumulation factor decreases in the order Cu (0.69-25.03) > Cd (0.68-3.19) > Zn (0.39-1.50) > Pb (0.0005-0.16) > Ni (0.01-0.12) > Co (0.0026-0.02) > Cr (0.0001-0.006), while for achenes, the order is Cd (0.53-7.07) > Cu (0.84-5.62) > Zn (0.83-1.24) > Ni (0.07-0.18) > Pb (0.04-0.09) > Cr (0.0010-0.0127) > Co (0.0013-0.0052).  
Corn and sunflower, as high-biomass-producing plants, exhibit a notable capacity for the bioaccumulation of heavy metals in comparison to wheat. This study presents evidence indicating that corn and sunflower demonstrate a greater susceptibility for the bioextraction of copper, zinc, and cadmium.  
Figure 12: Bioaccumulation factor of heavy metals in sunflower leaves and achenes.