Assessment of Heavy Metal Content of the Groundwater of Basilan Province, Bangsamoro Autonomous Region in Muslim Mindanao (BARMM), Philippines

Abstract

This study evaluates the groundwater quality in various municipalities of Basilan, focusing on the concentrations of heavy metals and overall water safety. Sampling wells were analyzed for parameters including mercury (Hg), arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), zinc (Zn), manganese (Mn), nickel (Ni), chromium (Cr), lead (Pb), and barium (Ba). Results indicate that most wells showed acceptable levels for these parameters, with notable exceptions: localized iron exceedances in wells SW4, SW1, and SW3, and consistently high arsenic levels 5.00 across all municipalities, raising significant health concerns. The Compound Pollution Index (CPI) values were generally below 1, suggesting that the groundwater is safe for drinking. However, the Heavy Metal Pollution Index (HPI) revealed slight contamination in certain areas, while Sumisip, Moh. Ajul and Lamitan City reported no contamination. The Excellent Water Quality Index (EWQI) further confirmed that the groundwater is classified as excellent across all sampled sites. These findings highlight the necessity for regular monitoring and investigation into sources of contamination, particularly concerning arsenic levels, to safeguard public health and maintain water quality in the study area.