Concentrations and bioaccessibility of metals in vegetation and dust near a mining haul road, Cape Krusenstern National Monument, Alaska

Abstract

Vegetation, sub-surface peat, and road dust were sampled near the Delong Mountain Transportation System (DMTS) haul road in northwest Alaska in 2005-2006 to document aluminum, barium, cadmium, lead, and zinc concentrations, and to evaluate bioaccessibility of these metals. The DMTS haul road is the transport corridor between Red Dog Mine (a large-scale, lead-zinc mine and mill) and the coastal shipping port, and it traverses National Park Service lands. Compared to reference locations, total metal concentrations in four types of vegetation (birch, cranberry, and willow leaves, and cotton grass blades/stalks) collected 25 m from the haul road were enriched on average by factors of 3.5 for zinc, 8.0 for barium, 20 for cadmium, and 150 for lead. Triple rinsing of vegetation with a water/methanol mixture reduced metals concentrations by at most 50%, and cadmium and zinc concentrations were least affected by rinsing. Cadmium and zinc bioaccessibility was greater in vegetation (50% to 100%) than in dust (15% to 20%); whereas the opposite pattern was observed for lead bioaccessibility (<30% in vegetation; 50% in dust). Barium exhibited low-to-intermediate bioaccessibility in dust and vegetation (20% to 40%), whereas aluminum bioaccessibility was relatively low (<6%) in all sample types. Our reconnaissance-level study indicates that clean-up and improvements in lead/zinc concentrate transfer activities have been effective; however, as of 2006, metal dispersion from past and/or present releases of fugitive dusts along the DMTS road still may have been contributing to elevated metals in surface vegetation. Vegetation was most enriched in lead, but because bioaccessibility of cadmium was greater, any potential risks to animals that forage near the haul road might be equally important for both of these metals.

Trends in spatial patterns of heavy metal deposition on national park service lands along the Red Dog Mine haul road, Alaska, 2001–2006

“…The Pb and Zn-enriched dusts deposited on the tundra initially contain these metals in reduced sulfide forms (Exponent 2007), which tend to exhibit low bioaccessibility [33]. Over time chemical weathering and exposure to air will oxidize these contaminants to more bioavailable forms.…”

Application study on complex wetting agent for dust-proof after gas drainage by outburst seams in coal mines

“…Its main ingredient is surfactant, some chemical additives and inorganic salt which can help to develop some new features, so that the wetting agent's effect can be optimized [20,21]. To determine the optimal mixture proportions having the best wetting effect and cost performance, the character and mixture principles of surfactant and inorganic salts were researched and five kinds of wetting agents were made.…”

Mineral constraints on arctic caribou (Rangifer tarandus): a spatial and phenological perspective

“…Road dust blown from trucks carrying mining ore have also been shown to contaminate vegetation concentrating potentially toxic levels of lead and zinc in downwind forages (Brumbaugh et al. ). However, windblown dust only has been detected on forages within 1.5 km from roads in Alaska's arctic, which is a small portion of the summer range (Walker and Everett ).…”

“…Roads perpendicular to migration routes on the range of WAH caribou may have a greater effect on migration routes, thereby limiting foraging time on autumn ranges (Wilson et al 2016). Road dust blown from trucks carrying mining ore have also been shown to contaminate vegetation concentrating potentially toxic levels of lead and zinc in downwind forages (Brumbaugh et al 2011). However, windblown dust only has been detected on forages within 1.5 km from roads in Alaska's arctic, which is a small portion of the summer range (Walker and Everett 1987).…”