VOL. 10, NO. 12, DECEMBER 2015 ISSN 1990-6145 ARPN Journal of Agricultural and Biological Science © 2006-2015 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 458 SEM/EDX ANALYSIS OF THE ROOTS OF WATER HYACINTHS (Eichornia crassipes) COLLECTED ALONG PASIG RIVER IN MANILA, PHILIPPINES Maria Cecilia Galvez 1 , June Francis De Guzman 1 , Steven Doniel Gueco 1 , Jeane Camelo 2 , Red Castilla 1 and Edgar A. Vallar 1 1 Environment and Remote Sensing Research (EARTH) Laboratory, Physics Department, De La Salle University, Taft Avenue, Malate, Manila, Philippines 2 Institute of Civil Engineering, G/f MelchorHall Osmeña Avenue, Diliman, Quezon City, Philippines E-Mail: maria.cecilia.galvez@dlsu.edu.ph ABSTRACT To study the possibility of using water hyacinths (Eichornia crassipes) as bioindicator of water pollution along Pasig River in Manila, Philippines, elemental analysis on the roots of water hyacinths was performed using scanning electron microscope equipped with energy dispersive X-ray analysis (SEM/EDX). For water samples a Total X-ray Fluorescence Spectroscopy (T-XRF) was used. Samples of water hyacinths were collected at four well-known bridges (Jones Bridge, Mabini Bridge -formerly Nagtahan Bridge, Makati-Mandaluyong Bridge, and Bambang Bridge) from February - April 2011. For comparison, samples were also taken from a swamp at Tulay na Bato, Daet, Camarines Norte, Philippines where no known pollutants were recorded and this site is free from any anthropogenic sources. All water samples were found to contain elements like S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, Br, Sr, and Al. Co was detected only in Jones Bridge and the concentration of Cu in Mabini Bridge exceeded the maximum allowable limit of 0.05 ppm. Elements found in the water samples, such as Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, and Al were also present in the roots of water hyacinths. Result of elemental analysis using EDX also showed that heavy metals like Pb and Hg were not detected in the epidermis and cross-section of the samples collected in Camarines Norte site but they were detected in the roots of water hyacinth collected along Pasig River. Keywords: water hyacinths, roots, SEM/EDX, Pasig River. INTRODUCTION Plants have been known to accumulate essential metal ions (Fe, Mn, Zn, Cu, Co, etc) as well as non- essential metal ions that are toxic to soil and water (Schor- Fumbarov et al., 2003). Large amounts of heavy metals can be detected in the roots due to absorption that commonly occurs in the root system, where it is in direct contact with pollutants (Bernd, 1993). The metal ions from the roots can either be stored in the stems or moved through the xylem to the shoot (Baker and Walker, 1990). Water hyacinths (Eichhornia crassipes) popularly known in the Philippines as water lilies are very common plants found in ponds, ditches, muddy lakes, and mostly shallow water. They reproduce easily and have the capacity to release up to 2,000 seeds (Salt et al., 1993). During rainy season these plants pose a threat to rivers and floodways due to clogging drains. Because of this, water hyacinths are considered as invasive alien species in the Philippines (MacKinnon, 2002). Some species of these plants have been reported to grow in toxic environments such as sludge and polluted rivers. Studies have shown that water hyacinths are able to accumulate heavy metals such as Cd, Pb, Hg, Mn and Fe at substantial amounts without being toxic to the plant (Lavid, et al., 2001). Figure-1. Map showing the sampling sites along Pasig River (Map data ©2015 Google).