Clean water and sanitation is one of the Sustainable Development Goals set by the United Nations, supported by 193 countries all over the world. In the Philippines, nearly 5 million Filipinos rely on unsafe and unsustainable water sources (Water.org, 2021). With a growing population, especially in urban areas, water pollution, wasteful and inefficient use of water, and forest denudation in watersheds, the country’s water resources remained to be threatened (ADB, 2012). Additionally, water contamination due to increase in demand of gold and other mining products affect nearby water bodies which eventually lead to serious diseases among the settlers. Fortunately, in 2019, Dr. Shirley T. Palisoc of the National Research Council of the Philippines (DOST-NRCP) Scientific Division of Physics spearheaded the Project titled, Development of Low-Cost and Portable Electrochemical Sensor for Heavy Metal Detection in Water.
In collaboration with Dr. Michelle Natividad, Dr. Palisoc was able to fabricate the Bismuth nanoparticle (BiNP)/Nafion modified screen printed electrodes through screen printing and drop coating. For testing the developed technology, the researchers acquired real samples of filtered tap water, unfiltered tap water, treated wastewater, and water obtained from Manila Bay to detect and analyze metals such as lead and cadmium via anodic stripping voltammetry (ASV) and atomic absorption spectroscopy (AAS). Upon testing, they discovered that the lead and cadmium levels of the water from Manila Bay is beyond the safe limits according to the standards set by the U.S. Environmental Protection Agency and the World Health Organization. On one hand, other water samples contained a trace amount of lead (1-2 pbb). The treated wastewater contained the least amount of lead while the unfiltered sample recorded the highest which are within the tolerance levels per the standard of government agencies.
The fabricated electrode modified with bismuth nanoparticles and 1% (v/v) Nafion® can be used for on-site environmental monitoring due to its portability and compact design. The Project recommends a routine analysis of water and aquatic systems in the country as well as devising of strategies to reduce heavy metals’ water contamination.