Spatial and Seasonal Patterns of Mine Dust and Metal Deposition Near Two Open Pit Metal Mines in Northern Sweden
摘要
Fugitive dust and metal deposition from mining operations pose potential risks to human health and the environment. This study investigated the spatial extent and seasonal dynamics of dust and metal deposition from two open-pit metal mines (copper and iron) in northern Sweden. Monthly passive dust sampling was conducted during 2022–2023 across 50 locations, up to 22 km from mine perimeters, and analysed in relation to proximity to mines, climate, and prevailing winds. Passive NILU dust-deposition measurements were evaluated against reference-grade particulate matter PM10 and PM2.5 at three distances from the copper mine, and snow samples were analysed for elemental deposition and concentrations for one winter. Dust deposition rates were positively correlated with PM10 and PM2.5, peaking near the mines at downwind sites during months with strong maximum winds. Seasonal peaks occurred in spring and summer and were primarily driven by maximum downwind wind speeds and proximity to the mines rather than temperature or precipitation. Sites within ~ 1 km of mine perimeters experienced the highest deposition rates, although elevated dust deposition extended ~ 5–10 km downwind during months with strong winds. High-exposure zones, defined as areas within ~ 1.6 km of the mine and downwind > 3% of the time under non-calm winds (≥ 1 m/s), exhibited median dust deposition rates of 130 g/100 m2 per 30 days, compared to 25 g/100 m2 per 30 days at distant, upwind low-exposure sites. Elemental deposition generally declined with increasing distance from the mines and increased with higher downwind frequency at the copper mine. Near-mine, downwind metal(loid) deposition at the high-exposure sites of the copper mine exceeded levels at the low-exposure sites by approximately 20–50 × , with the greatest enrichment observed for Sb and Co, followed by Mn, Cr, Pb, Zn, Cd, and V, and lower enrichment for Mo, As, and Cu. At the iron mine, corresponding high-exposure deposits exceeded low-exposure levels more moderately (~ 2–7 ×), with relative enrichment decreasing in the order Fe > Mn > Cr > Co > Cu > V > As > Mo. These results identify environmentally relevant high-exposure zones, provide a baseline for monitoring and mitigation, and demonstrate the value of passive dust monitoring alongside standardized protocols and complementary PM measurements. Future studies should examine how climate, topography, vegetation, mining activity, particle size, and mineralogy interact to control dust deposition.