Size fractionation in mercury-bearing airborne particles (HgPM10) at Almadén, Spain: Implications for inhalation hazards around old mines

Almadén has a >2000y mining history and an unprecedented legacy of mercury contamination. Resuspended airborne particles were extracted from mine waste (Las Cuevas), retort site soil (Almadenejos), and urban car park dust (Almadén), separated into fine (PM10) and coarse (PM>10 μm) fractions, analysed for mercury using ICP-MS, and individual HgPM characterised using SEM. Cold extractable mercury concentrations in PM10 range from 100 to 150 μg g−1 (car parks), to nearly 6000 μg g−1 (mine waste), reaching a world record of 95,000 μg g−1 above the abandoned retort at Almadenejos where ultrafine HgPM have pervaded the brickwork and soil and entered the food chain: edible wild asparagus stem material from here contains 35–65 μg g−1 Hg, and pig hair from animals living, inhaling and ingesting HgPM10 at the site yielded 8–10 μg g−1. The PM10 fraction (dusts easily wind transported and deeply inhaled) contains much more mercury than the coarser fraction. The contribution of HgPM10 to ecosystem contamination and potential human health effects around old mercury mines has been underestimated.