Soil quality changes in an Iberian pyrite mine site 15 years after land reclamation

Reclamation of highly degraded mine lands to a sustainable environmental quality has become major policy concern in many countries with long mining tradition. This paper reports the soil status historical site fifteen years after its reclamation, using indicators chemical reactivity, fertility and health, discusses progress effectiveness implemented measures by comparative analysis between pre- post-reclamation conditions. Twenty composite surface samples (0–20 cm depth) were obtained for physical characterization from open pit waste disposal area, stratified random sampling approach. Additionally seven sites selected collect topsoil microbiological testing. Results showed that changed noticeably over study period (2003–2018), overall improvements key properties, such as structural stability, cation exchange capacity, degree base saturation, organic carbon, available phosphorus. Prior was unable support vegetation due hyperacidity coupled elevated levels toxic metals nutrient deficiencies. The combined use sugar beet lime composted biosolids low-cost, locally available, amendment effective neutralizing both active exchangeable acidity, reducing mobility, plant uptake human bioaccessibility trace elements. addition also enhanced fertility, carbon storage, availability microbial biomass (bacteria fungi). Revegetation Pinus pinea Nerium oleander proven be successful strategy create vegetative cover aesthetically pleasant environmentally compatible surrounding undisturbed landscape, although further efforts should made monitor time phytotoxic bioaccessible residual metals, notably Cd, Cu Zn. insights gained this land reclamation experience provide success criteria assisting natural attenuation other abandoned worldwide.