Investigating the Relationship Between Bioavailability of Heavy Metals with Physical, Chemical, and Biological Characteristics of Soil in Different Land Uses

Evaluating the bioavailability of heavy metals and determining the effective parameters of bioavailability play a key role in the management and remediation of contaminated soils. In various land uses with different soil properties (physical, chemical, and biological), there were different factors affecting heavy metals' bioavailability. The present study was conducted in order to investigate the relationship between the heavy metal’s bioavailability with the physical, chemical, and biological properties of soil in agricultural, industrial, and urban land uses in Arak city. One hundred surface soil samples were randomly collected from these three land uses, and their physical, chemical, and biological parameters were measured. By statistical methods, soil properties were compared for agricultural, industrial, and urban land uses. The correlation between heavy metal bioavailability and soil properties was calculated using Spearman's test. Based on the obtained results, there was a statistically significant difference between different land uses in terms of CEC, microbial respiration, CaCO3 and organic matter (p<0.05). Also, there was a statistically significant difference between different land uses in terms of the bioavailability of cobalt, manganese, zinc, copper, nickel and lead and the total amounts of copper, lead and zinc (p<0.05). In agricultural land use, clay percentage, soil pH and EC; for industrial land use, EC, the percentage of clay, sand, silt, carbonate, organic matter, CEC, and microbial respiration, and in urban land use, the percentage of silt, organic matter, microbial respiration, carbonate, CEC, and EC have a significant correlation with the metal’s bioavailability. In all three investigated land uses, EC has a significant correlation with the bioavailability of heavy metals and EC is an effective parameter in all three land uses. Meanwhile, EC, CEC, soil texture, microbial respiration, carbonate, and organic matter are effective parameters in the bioavailability of heavy metals in different land uses and these parameters should be managed in order to remediate the contaminated soils. For this purpose, considering the negative correlation between carbonate and pH and the bioavailability of heavy metals, it is possible to suggest the use of lime for the remediation of the studied soils.