International Journal of Multidisciplinary Research and Publications ISSN (Online): 2581-6187 43 Mariano, Louie Ian B., “Health Risk Assessment of Heavy Metals via Ingestion and Dermal Absorption of Water in Mogpog and Boac Rivers, Marinduque, Philippines,” International Journal of Multidisciplinary Research and Publications (IJMRAP), Volume 1, Issue 9, pp. 43-50, 2019. Health Risk Assessment of Heavy Metals via Ingestion and Dermal Absorption of Water in Mogpog and Boac Rivers, Marinduque, Philippines Mariano, Louie Ian B. 1 1 College of Liberal Arts and Sciences, Colegio de San Juan de Letran, Manila, Philippines Email address: louieian. mariano@letran. edu. ph Abstract— The purpose of this paper was to assess the potential human health risk posed by heavy metals in surface water in Marinduque, specifically Boac and Mogpog River. Secondary data from Regional Environmental Management Bureau were used. The health risk assessment was patterned from the model made by the United States Environmental Protection Agency (US EPA) In this study, the pathways of exposure considered were ingestion, and dermal absorption of water pathways. Result revealed that the mean concentrations of the heavy metals in water varied significantly. Among the two exposure pathways for children, dermal absorption provided a higher Hazard Quotient (HQ) for copper, lead and cadmium. On the contrary, for adults only copper and lead have higher HQ of dermal absorption pathway. Hazard indexes (HI) for adult and children via different exposure pathways were found to be less than the standard value of 1. This means that there is less potential to non-carcinogenic health effects and risks. More so, adults were more at risk to cancer via ingestion of water while for dermal absorption exposure pathway children were more at risk. Keywords— Dermal Absorption: Hazard Index: Hazard Quotient: Health Risk Assessment: Heavy Metals: Ingestion. I. INTRODUCTION World’s urban communities are increasing faster than global population as the urbanization progresses (UN- HABITAT, 2004) (Mahmood and Malik, 2014) in the less- developed countries. Though urbanization, to a certain extent, provides economic comfort, it is one of the factors that alter certain environmental condition by increasing waste material build-up through different man-made activities (Mahmood and Malik, 2014). Two of the most important causes of heavy metal contamination in the environment are mining exploitation and ore smelting. According to Liang et al. in 2017, severe heavy metal contamination is brought about by the huge quantity of wastes produced in mining industries. This heavy metal concentration alters ground and surface waters, agricultural soils and food crops. It even poses great health risk to human population thru different exposure pathways. Environmental pollution arises and becomes one of the biggest concerns of humans today. As time passes by, environmental pollution worsens becoming a major threat to public health on a global scale (Neris et al., 2019). Heavy metals in waste water drained from tailing ponds pose a serious threat to the environment and to human. Mine tailing wastewater may contain but not limited to different heavy metals like copper, lead, cadmium and mercury. Mine tailing can percolate in the groundwater sources through seepage. According to Amari et al. (2017) and World Health Organization (WHO) (1993), heavy metals pose a cancer risk to human. The effect of heavy metal contamination occurs in the environment through different exposure methods and pathways (Liang et al., 2017) which includes direct ingestion, skin contact, and inhalation. Lenntech (2004), Dinis and Fuiza (2011) defined heavy metal as elements with high densities. These are also considered toxic even at low concentrations in soil and water sources. These group of elements include cadmuim (Cd), copper (Cu), chromium (Cr), iron (Fe), lead, (Pb), silver (Ag) and zinc (Zn) (Farlex, 2005; Duruibe et al., 2007). These metals are the most frequent environmental wastes and the presence in different water sources could be due to either natural or anthropogenic activities. Natural sources may occur because of chemical weathering of minerals and leaching (Titilawo et al., 2018) while mining of ore and smelting of metals are few of the anthropogenic activities by which it can be transferred to the environment. Groundwater and surface water contamination by heavy metals continues to become a serious threat to the ecological systems in the environment. Although trace concentrations of micro-nutrient heavy metals – Fe, Cu and Zn – an increase concentration still poses toxic effects to the physiology of living organisms (Baby et al., 2010; Nair et al., 2010; Manoj et al., 2012). Meanwhile, Cd and Pb are extremely poisonous even at a low concentration and bioaccumulates in body tissues over long period of time which leads to affect human health negatively (Titilawo et al., 2018). Since source contamination occurs in different ways, exposure pathways occur differently. According to Neris et al. (2018), there are three pathways by which exposure to heavy metals can occur – soil and sediment; surface and groundwater and particulate matter and vapors (U.S. EPA, 1989). According to Neris et al. in 2018, in industrial set-up humans are continuously subjected to contaminants in the site source and the vulnerability are assessed for contacts to surface soil and water. In most cases, the main exposure pathways are ingestion, dermal contact and inhalation of particulate matter. More so, adults and children are at higher risk than those in the industrial set-up because the exposure is determined for a lifetime duration (Neris et al., 2018) and that consumption of food is also taken into consideration. In this study, exposure