Abstract:
Soil can retain heavy metals originating from various sources, especially Cr (VI), which in
turn poses a risk to humans and the environment and this risk leads to the need to evaluate soil
properties.
In this study, soil quality, physicochemical properties and the extent of hexavalent chromium
contamination were assessed. Samples were taken from multiple locations in the city of Djelfa
(agricultural, industrial and residential areas) and were analyzed in the laboratory, including
pH measurement to determine soil reactivity, organic matter and water content as indicators
of fertility level, electrical conductivity reflecting soil salinity, and hexavalent chromium
concentration using UV-visible technique to determine the degree of contamination.
Based on the experimental procedure, the results obtained indicated the average pH (7.64),
OM (3.91%), WC (5.38%), EC (0.1mS/cm) and Cr (8.28mg/kg).
Then, the relationship of soil properties on Cr(VI) concentration was evaluated based on the
external influences on the sample site, where we found that both organic matter and pH
increase the deposition, oxidation and reduction of Cr(VI) in the soil, and pollution sources
such as car smoke, tanning and fertilizers positively affect the increase in Cr(VI)
concentration.
Description:
Based on our experimental results, we reached the following conclusions:
Physical and chemical analyses of soil properties (OM, pH, EC, WC) showed that they
are directly related to the level of Cr (VI) concentration in the soil.
Cr (VI), EC and OM were the most important factors in explaining the variation of
soil properties between samples.
Relatively high levels of Cr (VI) were recorded at some sites, indicating the presence
of pollution sources.
High concentrations of Cr (VI) were associated with soils with lower pH values,
indicating increased metal mobility under these conditions.
Low concentrations of Cr (VI) were recorded in soils with acidic pH values, indicating
the oxidation of chromium to its less toxic counterpart chromium (III).
Organic matter contributes to the stabilization and transformation of Cr (VI) in the soil.
As perspectives of this work, we suggest to do deep research on hexavalent chromium
distribution and effects on flora and fauna, and also, we think that a proposition of Cr (VI)
removal method will be a good continuation of this subject. It may be a good idea if we apply
AI to predict the Cr (VI) pollution in the future and to find solutions for this problem
