Effect of Ballast Water on the Growth of Two Aquatic Macrophytes (Azolla pinnata R.Br and Lemna paucicostata Hegelm)

Abstract

The study investigated the effect of ballast water on the growth of two aquatic macrophytes, Azolla pinnata R.Br. and Lemna paucicostata Hegelm. The ballast water used for this study was sourced from MTCRARROCH vessel which berthed in Koko Port. The macrophytes were grown at different concentrations (25%, 50%, 70% and 100%) of ballast water, using distilled water as control (0%). The experiment lasted for twelve (12) days. There was increased growth in both macrophytes with increasing concentration of ballast water. There was an increase in the growth of both macrophytes at all concentrations from the beginning to the end of the experiment. Of both test macrophytes, L. paucicostata was more tolerant to ballast water. The ballast water was acidic (pH 6.7) and with high electrical conductivity (1790 μS/cm). Iron, zinc, lead and cadmium were within the permissible limits of Standard Organization of Nigeria and the World Health Organization. Water quality parameters such as pH, electrical conductivity, total dissolved solids, salinity, dissolved oxygen, biochemical oxygen demand, NO₃, SO₄, PO₄, Fe, Pb, Zn, Cd; chlorophylls a and b, removal efficiency, percentage inhibition and yield were determined. Most of the water quality parameters of ballast water for the test macrophytes were significant.