Impact of Oxides and Physiochemical Properties of Agricultural Soil on Bioaccumulation of Toxic Heavy Elements in Wheat Grains in Yaychi, Northeast of Iraq

Abstract

To investigate the potential link between toxic heavy elements in soil with soil physiochemical properties and oxides, as well as their impact on the bioaccumulation of these elements in wheat grains. Agriculture soil and wheat grains were sampled from Yaychi area, Kirkuk northeast of Iraq. Soil physiochemical properties, oxides and toxic heavy elements contents were determined. The average concentration of toxic heavy elements in soil was in this order Ni> Cr> Pb> As> Cd> Hg, and some of these elements had exceeded their average in earth's crust and Canadian Agricultural Soil Quality Guidelines. While in wheat grains the toxic heavy elements, contents were in the following order Cr> Ni> Pb> As> Cd> Hg. The soil physiochemical properties in the study area are shown to be medium alkaline, non-saline, calcareous, non-gypsiferous, inorganic and loam texture. It became clear from the correlation matrix that the toxic heavy elements except for arsenic have significant relationships with different soil physiochemical properties and major oxides. In turn, oxides and the physiochemical properties of the soil and its type reduced the bioaccumulation of these elements in wheat grains except for arsenic, as appeared in the present study, that toxic heavy elements do not accumulate in wheat grains. And among the studied elements, arsenic had the highest bioaccumulation rate in wheat grains, because its concentration in soil has been affected by only human activities.

Geochemical Distribution of Some Heavy Metals in Agricultural Soil and Their Environmental Impacts in Kirkuk, Northern Iraq

“…It is also observed that the element concentration in all the studied samples is less than the two selected standard samples they are surface (SA6) is 130.44ppm and the subsurface (SbA6) is 132.59ppm. It may be related to the high application of fertilizers and herbicides in agriculture, which is an important source of nickel in the soil (Chauhan et al, 2008;Yasmeen et al 2010;Al-Jumaily and Hasseb, 2021). Or it is a result of the sulfur rich geological formations , such as the Fatha Formation exposed in the study area which contain gypsum quarries in the region, nickel exhibits high geochemical affinity with sulfur under reduce conditions, and the element is concentrated in rich organic contain clays and precipitates as sulfide (Rankama and Sahama, 1950;Butu, 2013).…”