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In the Philippines, legacy mines and active mine wastes pose potential threats since these may contain elevated concentrations of potentially toxic elements (PTEs) and high natural radioactivity. In this study, legacy mine wastes from the Philippine Iron Mine (PIM), Barlo Mine (BM), and Rapu-Rapu Mine (RRM) and active mine tailing from Padcal Mine (PM) were analyzed to determine the concentrations of fifteen (15) PTEs and the activity concentrations of natural radionuclides. Several quantitative risk indicators and radiological health risk parameters were utilized to determine the potential effects of these mine wastes to the natural environment and to human health. Legacy mine wastes have higher contents of PTEs and are more polluted by PTEs than PM tailing. Both enrichment factor (EF) and geoaccumulation index (Igeo) values suggest that legacy mine wastes are strongly polluted by As, Cd, Cu, and Mo. BM and RM wastes are also polluted by Pb, Sb, and Zn; PIM waste is polluted by Ni and V; and BM waste is polluted by Tl. Padcal mine tailing is only moderately polluted by Cu and Mo. The natural radionuclide activity concentrations of legacy and active mine wastes are below the global background values and the radiological hazard indices are also all lower than their permissible limits, except for 40K, 238U, and absorbed gamma dose rate in PIM due to a geogenic source. Unlike the PTEs, radioactivity in the legacy and active mine wastes are not enhanced by mining activities and is not a significant risk factor to human health. [ABSTRACT FROM AUTHOR]

Abandoned mines pose high risks to human health and the environment due to the disturbed and exposed metal-laden soils and sediments. In this study, soils and sediments in an abandoned mercury (Hg) mine in Puerto Princesa City, Philippines were analyzed to assess the potential adverse health effects of the exposure to trace metals associated with the mine wastes. A total of 63 soil and sediment samples were collected in the area and analyzed for Hg concentration using a direct Hg analyzer and inductively coupled plasma--mass spectrometry (ICP-MS) for other trace metals. Analysis results showed that aside from Hg, there are anomalous concentrations of Ni (nickel), Cr (chromium), and Mn (manganese) in the area brought by the value of the mineralogy of the ores that were mined. The measured trace metal concentrations, together with the United States (US) Environmental Protection Agency's (EPA) exposure parameters and the US Department of Energy's (DOE) toxicity values were used to calculate the dose contacted from different exposure pathways. The result of the health risk assessment showed that Hg was considered as the main contributor of non-carcinogenic risk in the area with a hazard index of > 1 for both children and adults. Inhalation of Hg vapor from the soils and sediments is found to be a significant addition to the health risks in the area. Other trace metals such as Co (cobalt), Fe (iron), Ni (nickel), and Tl (thallium) were calculated with a hazard index greater than 1, which poses a health risk to children due to the ingestion pathway. All carcinogenic trace metals assessed were below the guidance value, indicating no significant carcinogenic health risks for both adults and children in the area. This work serves as an initial step of the country in the assessment of the risks to human health and the environment brought by Hg contaminated areas, as stated in the Minamata Convention on Mercury. [ABSTRACT FROM AUTHOR]

The rising demand for critical metals presents a major economic opportunity for mineral-rich countries. For a sustainable transition to a low-carbon future, it is essential to minimise impacts of mineral resource development to the environment, ecosystems, and societies of these nations. Although there has been considerable progress in the social aspects of the mining sector, environmental metrics are not showing comparable improvement. The Philippines exemplifies this challenge as a country that aims to conserve its exceptional biodiversity to maximise ecosystem services while expanding mining activities for economic growth, in a geographical setting with high mineral potential and vulnerability to natural hazards and climate change. Similar to many mining areas, environmental baselines are mostly non-existent, compounded by a legacy of mining impacts despite an established policy framework. We review issues associated with large- and small-scale mining and identify underlying research challenges and opportunities in the Philippines. Potential environmental research pathways include (i) innovative approaches for catchment scale characterisation and identification of contaminant sources; (ii) quantifying and predicting contaminant transport; (iii) deployment of flexible monitoring devices for larger-scale water quality monitoring programmes; (iv) tailings dam monitoring and management; and (v) resource assessment and metal recovery in ores and tailings. By integrating geomorphological tools with geochemical data, as well as 2D/3D numerical modelling techniques, it becomes possible to predict and understand the behaviour and fate of contaminants across different spatial and temporal scales. The development of cost-effective water quality assessment devices and protocols can help overcome logistical challenges in monitoring a wider range of hydrological conditions. Advanced applications of remote sensing, combined with machine learning, and geophysical monitoring systems provide new opportunities to detect mining footprints and observe change in tailings dams more effectively. Potential impacts of mine wastes can be further minimised by exploring innovative technologies such as the use of metal-accumulating native plant species and environmentally safe solvents to reprocess modern and legacy tailings. Insights from these pathways will enable the realisation of a more sustainable mining future, through the incorporation of findings into existing and future governmental and small- and large-scale mining policy and practice. This will lead to sustainable development for society, particularly in nations that are well positioned to benefit from sustainable mineral resource development. [Display omitted] • The Philippines is mineral-rich and a global biodiversity hotspot. • Five environmental research challenges and opportunities are identified. • Contaminant management needs geochemical observations and geomorphological models. • National-scale water quality monitoring needs bioavailability-based devices. • Native plants & organic solvents have potential for ore and tailings metal extraction. [ABSTRACT FROM AUTHOR]