Zinc fractionation of tropical paddy soils and their relationships with selected soil properties

The Monitoring of Selected Heavy Metals Content and Bioavailability in the Soil-Plant System and Its Impact on Sustainability in Agribusiness Food Chains

This study assisted in identifying and preventing the increase in heavy metals in soil and winter wheat. Its accumulation can affect cultivated crops, quality and crop yields, and consumers’ health. Selected heavy metals were analyzed using the GTAAS method. They were undertaken on selected heavy metals content (Cd, Cu, Pb, and Zn) in arable soils at three sites in Slovakia and their accumulation in parts of cultivated winter wheat. Our study showed that the limit value of Cd in soil samples was exceeded in the monitored arable soils from 2017–2019. The average content values of Cu and Zn did not exceed the limit values, even in Pb values (except for the spring period). The analyses also showed that the heavy metals content for plants bioavailable in soil did not exceed the statutory critical values for Cd, Cu, and Zn’s average content values. However, Pb content exceeded permitted critical values. Heavy metals bioaccumulation (Zn, Cu) was within the limit values in wheat. Analyzed Cd content in wheat roots and Pb content were determined in all parts of wheat except grain. The study showed that grain from cultivated winter wheat in monitored arable soils is not a risk for consumers.

Distribution of selenium and zinc in soil-crop system and their relationship with environmental factors

Selenium (Se) and zinc (Zn) are essential microelements for humans with crucial biological functions. In this study, we determined Se and Zn concentrations in soils and rice grains on Hainan Island and investigated how their spatial distributions are related to soil mineral elements, topography, and vegetation coverage. Overall, the concentrations of Se and Zn in soils were higher than the background values for Chinese soil; the Se concentrations in rice grains were higher than the threshold value for Se deficiency in grains, but Zn concentrations were lower than the proposed critical concentration. Both Spearman's correlation and stepwise regression analysis showed that the concentrations of soil Fe and Ca significantly affected soil Se and Zn: a difference of 1 g kg^-1 in soil Fe changed soil Se by 2.820 μg kg^-1 and soil Zn by 0.785 mg kg^-1, respectively, while a difference of 1 g kg^-1 in soil Ca changed soil Se by 3.249 μg kg^-1 and soil Zn by 0.356 mg kg^-1, respectively. For rice grains, Se and Zn concentrations decreased with increasing elevation; every 100 m increase in elevation could decrease Se by 0.022 mg kg^-1 and Zn by 0.912 mg kg^-1. Moreover, the impact of Fe and Ca on soil Zn was relatively strong in the northeast region, while the influence of elevation on rice grain Se was more significant in the central region. The findings contribute to a better understanding of factors driving the distribution of Se and Zn in soils and crops.