## 4 Discussion  
Oriental Mindoro, an island province, is vulnerable to GW pollution and degradation due to natural and human activities. Due to structural disadvantages and characteristics such as smaller land area and population, insufficient natural resources, geographical distribution, and other global factors beyond domestic control, a small island economy is less resilient to the threat of GW deterioration and contamination than larger and more diverse economies [70]. Water plays a critical part in achieving the United Nations' Sustainable Development Goals (SDGs). One of the problems that population has been experiencing is ensuring that everyone achieves SDG 6 (clean water and sanitation) which seeks to guarantee universal access to, and sustainable management of water. Continuous data integration and frequent monitoring remain to be critical components to achieving SDG 6 [71]. Hence, creating tools to aid in carrying out GW monitoring is significant. Tools such as the hybrid NN-PSO+EBK in making GW monitoring convenient to researchers and authorities are important. Various heavy metals were detected at various sampling sites across Calapan City. The mean concentration of these metals in GW remained below the WHO and PNSDW acceptable levels. The recorded in-situ physicochemical characteristics were also compared to the WHO and PNSDW acceptable limits. The average GW temperature observed in the study area was 29.99 \({}^{\circ}\)C while the average GW pH observed was 7.69. Both figures are within the permissible range of WHO and PNSDW. One (1) sampling location exhibited pH value exceeding the maximum limit for pH of PNSDW. The average EC for the area of study was 560.36 \(\upmu\)S/cm. This is within the permissible limit of the WHO. One (1) sampling location exhibited an EC value exceeding the WHO limit of 1500 \(\upmu\)S/cm. The EC observation made in this location was categorized as Type II. The EC greater than 1500 \(\upmu\)S/cm but less than 3000 \(\upmu\)S/cm implies medium salts enrichment [72]. The average TDS is 277.15 ppm which was below the maximum allowable limit by the PNSDW and WHO. Though, TDS levels did not exceed the permissible limits set by WHO and PNSDW but were substantially lower or higher than the suggested TDS range of 600\(-\)1000 impairing palatability. Specifically, data of water samples from Ibaba West recorded TDS of 900. This number is at the high side of the limit which suggested the probability of impaired taste. On the other hand, the TDS concentrations recorded in Balingayan (60), Biga (50), Canubing (50), Comunal (90), Ibaba East Site 1 (160), Managpi (100), Personas (60), and Sta. Rita (40) were all significantly lower than the recommended range (600\(-\)1000 ppm) which may result to flat and inspid flavor. The heavy metals concentration for GW was also observed in the study area. The Fe concentrations detected in multiple locations were above the WHO and PNSDW standards. However, the rest of the heavy metals detected were within the permissible limits. Water with elevated metals concentration has the potential to cause several public health issues. Health risks associated with elevated Fe in GW is probable. Pollutants entering the human body through drinking water have been shown in numerous studies to have detrimental health consequences for consumers. Micronutrients are essential in living organisms; how  
Figure 14: Summary of MSE per Barangay considering (**a**) Ba, (**b**) Cu, (**c**) Fe, (**d**) Mn, and (**e**) Zn. ever, elevated concentration adversely affects public health. Similar case with Mn which is necessary for humans; however, excessive quantities will have negative consequences. Neurological disorders, such as aberrant walking, ataxia, muscle hypotonicity, and a face devoid of lasting emotions, are frequently associated to Mn [64]. Dysfunction of liver was also reported [73]. Furthermore, excess Mn concentration has been demonstrated to produce neurotoxicity in infants receiving parenteral nonishment [74].