Dust-related impacts of mining operations on rangeland vegetation and soil: a case study in Yazd province, Iran

摘要

Destructive mining operations are affecting large areas of natural ecosystems, especially in arid lands. The present study aims at investigating the impact of iron mine exploitation on vegetation and soil in Nodoushan (Yazd province, central Iran). Based on the dominant wind, topography, slope, vegetation and soil of the area, soil and vegetation parameters close to the mine were recorded and analyzed according to the distance from the mine. To obtain the vegetation cover, a transect and plot on the windward and leeward side of the mine, with 100 m intervals and three replicates at each sampling location was used, yielding 96 soil samples. The amount of dust on the vegetation, the seed weight and seed germination rate of Artemisia sp. as the dominant species within the area, and the soil microbial respiration were measured. The relationship between vegetation cover and distance from the mine was not linear, which was due to an interplay between pollution from the mine and local grazing, while other factors did increase or decrease linearly. The results showed that, as the distance from the mine increased, the weight of 1000 seeds of Artemisia sp. was significantly increased from 271 to 494 mg and seed germination rate and soil microbial respiration were significantly increased from 11.7 to 48.4% and from 4.5 to 5.9 mg CO2 g(-1) soil day(-1), respectively, while the amount of dust significantly decreased from 43.5 to 6 mg (g plant)(-1) between the distance of 100 and 600 m from the mine in the leeward direction. A similar trend was observed in the windward side, though negative effects were lower compared to the same distance along the leeward sample locations. The direct and indirect effects on plant growth and health from mining impacts generally decreased linearly with increasing distance from the mine, up to at least 600 m. Our study serves as a showcase for the potential of bio-indicators as a cost-effective method for assessing impacts of mining activities on the surrounding environment.