Post-rehabilitation Heavy Metal Contamination Analysis of Kangkong (Ipomoea aquatica) Cultivated in the Pasig River Waterway, Manggahan Floodway
DOI:
https://doi.org/10.65166/xf4mm102Keywords:
kangkong, heavy metals;, Pasig River, Manggahan Floodway, Pasig River Rehabilitation Commission, Priver rehabilitation, environmental monitoringAbstract
The Pasig River, once classified as a biologically dead water body, has been the focus of rehabilitation efforts since 1999 under the Pasig River Rehabilitation Commission (PRRC). Following the Commission’s dissolution in 2019, this study assessed the effectiveness of the rehabilitation program by evaluating heavy metal contamination in locally cultivated kangkong (Ipomoea aquatica), a recognized bioindicator species, from one of its major waterways, the Manggahan Floodway. Fresh kangkong samples were collected from three sites and analyzed for lead (Pb), cadmium (Cd), and mercury (Hg) using validated American Public Health Association (APHA) methods: Inductively Coupled Plasma–Atomic Emission Spectroscopy (ICP-AES) for Pb and Cd, and Cold Vapor Atomic Absorption Spectrometry (CVAAS) for Hg. The results confirmed the presence of Pb (<0.00517 ppm), Cd (<0.0010 ppm), and Hg (<0.00004 ppm) in all samples; however, all concentrations were substantially below the respective method detection limits and far lower than the maximum levels permitted for leafy vegetables under the Codex Alimentarius General Standard for Contaminants and Toxins in Food and Feed (CXS 193-1995). Comparative analysis with previously reported rehabilitation-period data revealed a pronounced reduction in heavy metal concentrations over time. These findings indicate a marked improvement in environmental quality, support the conclusion that kangkong harvested from the study sites is safe for consumption with respect to these metals, and affirm the long-term effectiveness of the Pasig River rehabilitation initiatives.
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