Quantitative Study of Microbial Contaminant Attachment and Detachment in Calcareous Soil

Bacteria attachment to soil is an important component in bacteria transport models. The objective of this study was to quantify the influence of calcium carbonate on bacteria attachment anddetachment in calcareous soil. Consequently, 60 calcareous soil samples were collected from Central Province and their bacteria (Escherichia coli) adsorption isotherm, physical and chemical properties were measured. Three types of adsorption isotherms were evaluated. The results indicated that linear isotherm leads to a better prediction of bacteria attachment to calcareous soil in comparison with the Freundlich and Langmuir isotherms. A pedotransfer function was also derived to predict the kd parameter of the linear isotherm from soil particle size distribution and calcium carbonate content. The attachment and detachment of bacteria in three treatments of calcium carbonate content (10, 21 and 37%) were tested in a completely randomized design (CRD) with three replications. According to the results, increasing soil calcium carbonate content leads to enhanced equilibrium and kinetic bacteria attachment (p<0.05). Bacteria detachment also decreases by increasing soil calcium carbonate (p<0.05).