Elemental analysis of Ipomoea aquatica (kangkong) bought in different public markets located in Pasig and Taguig using scanning electron microscopy with energy dispersive x-ray analysis, atomic absorption spectroscopy and inductively coupled plasma-atomic emission spectroscopy

Date of Publication


Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Premed Physics

Subject Categories

Biological and Chemical Physics


College of Science



Thesis Adviser

Maria Cecilia Galvez

Defense Panel Chair

Edgar Vallar

Defense Panel Member

Christopher T. Que
Ernest P. Macalalad


lpomoea aquatica (Kangkong) leaves are aquatic plants that are annually present along the Pasig River, C6 or Laguna de bay. Kangkong leaves were acquired from 6 particular public markets around Pasig and Taguig namely, Pasig Palengke, Pasig Bagong log, Pasig Bagong llog High way, Oranbo-Pasig, C6 and Taguig. These leaves were harvested particularly from Laguna de bay or C6 on the day of collection, April 2016. Thereafter, the leaves were subjected under freeze-drying for preservation, which went through SEM-EDX analysis to determine the elemental composition of the leaf samples as well as their respective heavy metal contents. The heavy metals considered for this analysis la.re the following: Fe, Si, Mn, Cr, Co, Ni, Cu, Al, Zn, Pb, Hg and Se. However, for the ICP­IAES and AAS analysis only 3 sources went through analysis particularly Pasig Palengke, C6 and Taguig; and a water sample from the source of the leaves which is from the waters of Laguna de bay along C6. For the EDX analysis, carbon and oxygen have the highest wt­¼ concentrations and are significantly different from the other elements as seen in the boxplots, p-values, hierarchal cluster analysis and post-hoc Tukey HSD test. Sodium and magnesium concentrations compared to the other elements posed a significant difference in the boxplot analysis against other elements while the rest of the elements remained trace. Consistent with the results acquired from the AAS and ICP-AES analysis. Manganese and magnesium in particular were found to have high concentrations in the leaf samples examined in the AAS and ICP-AES analyses. As for water, it is only magnesium that had notable concentrations while the 8 remaining elements (Cu, Fe, Cd, Hg, Cr and Ni) were below detection limit. Indicating the water sample to be a possible source of magnesium in the plant while manganese may be from another source. Furthermore, the water sample did not exceed the permissible limits set by the Department of Environment and Natural Resources (DENR). Selenium, manganese, and chromium showed the least dissimilarity in the Hierarchal Cluster Analysis (HCA) of they were always clustered together in all the locations due to property as metal but also due to their function in plants as essential micronutrients except for chromium—up taken through roots as a result of fertilizers or industrial wastes. HCA is supported or is consistent as well with the results of the post-hoc Tukey HSD analysis identifying the essential micro and macronutrients in plants. Lastly, for the Principal Component Analysis, elements that greatly affected a particular factor often came in pairs such as carbon and oxygen however, the correlation may not always be positive in the case of C and 0. From the correlations of the elements, a common source may be delineated such as industrial wastes, smog from the passing vehicles and the naturally occurring elements in the plant.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F, Henry Sy Sr. Hall


Ipomoea aquatica—Heavy metal content—Philippines—Pasig; Ipomoea aquatica—Heavy metal content—Philippines—Taguig

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