Effects of aquatic plants on reducing salinity and cation concentrations in different types of water

The efficiency of some aquatic plants, i.e., Azolla filicoides, Ceratophyllum demersum, and Lemna minor, in reducing electrical conductivity (ECs) and some cations were studied in a laboratory experiment with three filter sizes (300, 400, and 500 cm³) for each plant and type of water. Two sources of water samples were collected: Shatt al-Arab (EC 7 dS m-1) and Shatt al-Basrah water, collected on October 5, 2022 (EC 60 dS m-1), and February 20, 2022 (EC 43 dS m-1 adjusted to 20 dS m-1), respectively. Filtered water was kept in plastic containers while the EC and cations reduction efficiencies were calculated. Based on the results, Azolla had the highest reduction efficiency among the filters, followed by Ceratophyllum and duckweed for the filter size equal to 500 cm³. The other filter sizes were less efficient than those with a volume equal to 500 cm³ or greater. The different sizes showed varying abilities in reduction, all less than those of the 500 cm³ size.