Abstract

Artisanal and small-scale gold mining (ASGM) degrades soil fertility and physicochemical quality while causing multi-metal contamination, underscoring the need for low-cost, environmentally friendly remediation strategies. This study evaluated the capacity of a plant growth-promoting rhizobacteria (PGPR) + arbuscular mycorrhizal fungi (AMF) consortium, applied without organic amendments or soil ameliorants, to improve degraded soil from a former artisanal gold mine. Soil was collected from an ASGM site in Kulon Progo, Yogyakarta, Indonesia. Seedlings of Capsicum frutescens were inoculated with a consortium of AMF and PGPR, while uninoculated seedlings served as controls. Soil pH, cation exchange capacity, water content, soil organic carbon, nitrogen, phosphorus, potassium, mercury (Hg), iron (Fe), cadmium (Cd), manganese (Mn), zinc (Zn), arsenic (As), aluminum, and sulfate were analyzed, together with selected metal concentrations in roots and shoots. ASGM reduced soil pH, fertility-related properties, and nutrient status, while increasing concentrations of several metals. AMF+PGPR inoculation improved selected soil properties, enhanced root colonization, and increased seedling biomass. Metal responses were selective rather than uniform: Accumulation of Hg, As, and Zn in plant tissues decreased, Fe and Mn translocation to shoots was maintained or enhanced, and Cd showed partial regulation. These findings indicate partial, early-stage improvement of ASGM-affected soil, but not full restoration.

Key words: AMF+PGPR consortium, artisanal and small-scale gold mining, soil quality improvement, multi-metal contamination, Capsicum frutescens.