Distribution of Enhanced Potentially Toxic Element Contaminations Due to Natural and Coexisting Gold Mining Activities Using Planet Smallsat Constellations

Abstract

Potentially toxic elements (PTEs) from natural and anthropogenic activities threaten the environment and human health. The associations of PTEs with natural hazards can be powerful and prominent mechanisms to release PTEs, considerably hastening their multiple contaminations and widespread distribution. This study primarily aimed to investigate the enhanced potential distribution of PTE contaminations (arsenic, lead, and mercury) from coexisting gold mining operations combined with massive riverbank erosion in Indonesia from 2002 to 2022, where soil and water are highly contaminated naturally, using PlanetScope smallsat constellations, Google Earth imagery, and hydrographic datasets. According to the findings, increased barren extents were found because of mining deposits and road network developments. Enhanced natural and anthropogenic PTE runoffs would be transported across two different sub-basins, affecting broader parts of the Bone River. Between 2002 and 2022, 139.3% of river expansion was identified, eroding a maximum of 3,436,139.4 m3 of contaminated soil. Particularly land surfaces were repeatedly transformed from rivers to agricultural lands in the low Bone River, possibly contaminated by fertilizer spills. The combination of PTE potentials from different sources would further exacerbate the contamination level at an estuary. These findings are expected to aid in the timely monitoring of and assuming volumes, rates, and distribution of PTEs from various natural and anthropogenic activities and alert PTE contamination risks to ecosystems and human health. Future work in this area should aim to investigate contamination levels at the estuary, where contaminated materials from both natural and anthropogenic activities are accumulated.