EMPLOYING CYANOBACTERIA SP. IN BIOREMEDIATION OF SALINE SOILS TO REDUCE WATER POLLUTION

Abstract

This study evaluated the influence of surface-applied wet algal biomass on key physicochemical properties of saline soil collected from the Abu Ghraib region of central Iraq. The algal mixture, a naturally occurring consortium obtained from a freshwater canal located within the University of Baghdad, was taxonomically identified as belonging to four major algal classes: Bacillariophyceae, Chlorophyceae, Cyanophyceae, and Zygnemataceae. These indigenous algae were applied to the soil surface to assess their capacity to modify salinity-related parameters through biological and physicochemical mechanisms. Temporal measurements of electrical conductivity (EC), total dissolved solids (TDS), NaCl percentage, and pH over 24, 48, 72, and 96 hours revealed distinct differences between the Control and algae-amended soils. The untreated Control showed a steady increase in EC, TDS, and NaCl%, indicating progressive dissolution and mobilization of inherent salts within the saline soil matrix. In contrast, soils treated with the algal mixture showed reductions in EC and TDS at most time points, reflecting decreased ionic strength and lower dissolved salt concentrations. NaCl% also declined at later intervals in algae-amended treatments, suggesting effective ion immobilization through biosorption, bioaccumulation, and organic matter interactions associated with the algal biomass. Soil pH remained relatively stable but exhibited slight alkalinization in some treatments, consistent with the release of basic cations and the decomposition of algal organic matter. Collectively, these results demonstrate that indigenous freshwater algae possess significant potential for reducing salt mobility and modifying the chemical behavior of saline soils when applied to the soil surface. The findings underscore the value of native algal communities as sustainable, low-cost bioremediation agents for managing salinity in agricultural systems such as those in Abu Ghraib. Furthermore, the study highlights the necessity of employing multiple salinity indicators (EC, TDS, NaCl%, pH) to capture the complex suite of interactions governing soil algae salt dynamics.