Spatial patterns of cadmium and lead deposition on and adjacent to National Park Service lands in the vicinity of Red Dog Mine, Alaska

Abstract

Heavy metal escapement associated with ore trucks is known to occur along the DeLong Mountain Regional Transportation System (DMTS) haul road corridor in Cape Krusenstern National Monument, northwest Alaska. Heavy metal concentrations in Hylocomium splendens moss (n = 226) were used in geostatistical models to predict the extent and pattern of atmospheric deposition of Cd and Pb on Monument lands. A stratified grid-based sample design was used with more intensive sampling near mine-related activity areas. Spatial predictions were used to produce maps of concentration patterns, and to estimate the total area in 10 moss concentration categories.Heavy metal levels in moss were highest immediately adjacent to the DMTS haul road (Cd N 24 mg/kg dw; Pb N 900 mg/kg dw). Spatial regression analyses indicated that heavy metal deposition decreased with the log of distance from the DMTS haul road and the DMTS port site. Analysis of subsurface soil suggested that observed patterns of heavy metal deposition reflected in moss were not attributable to subsurface lithology at the sample points. Further, moss Pb concentrations throughout the northern half of the study area were high relative to concentrations previously reported from other Arctic Alaska sites. Collectively, these findings indicate the presence of mine-related heavy metal deposition throughout the northern portion of Cape Krusenstern National Monument.Geospatial analyses suggest that the Pb depositional area extends 25 km north of the haul road to the Kisimilot/Iyikrok hills, and possibly beyond. More study is needed to determine whether higher moss heavy metal concentrations in the northernmost portion of the study area reflect deposition from mining-related activities, weathering from mineralized Pb/Zn outcrops in the This article is a U.S. government work, and is not subject to copyright in the United States.broader region, or a combination of the two. South of the DMTS haul road, airborne deposition appears to be constrained by the Tahinichok Mountains. Heavy metal levels continue to diminish south of the mountains, reaching a minimum in the southernmost portion of the study area near the Igichuk Hills (45 km from the haul road). The influence of the mine site was not studied. D

How robust are community-based plant bioindicators? Empirical testing of the relationship between Ellenberg values and direct environmental measures in woodland communities

“…Some systems rely on single species indicators, for example, the plant Astragalus racemosus for selenium concentration (Trelease and 40 Trelease, 1938) and the bryophyte Hylocomium splendens for heavy metal pollution (Hasselbach et al, 2005). However, the majority of indicator systems use community-based approaches whereby the presence (and sometimes abundance) of multiple species is taken into account.…”

Metal exposure and effects in voles and small birds near a mining haul road in Cape Krusenstern National Monument, Alaska

“…The haul road is the primary component of the Delong Mountain Regional Transportation System (DMTS) that also includes the mine and port facilities (Fig. 1); it traverses 32 km of CAKR land, for which a 100-year transportation easement was granted in 1985 by Congressional approval (Hasselbach et al 2005).…”

“…Moss sampled along the haul road corridor in 2000 contained elevated concentrations of cadmium (Cd), Pb, and Zn the source of which was attributed to escape of ore concentrate from trucks during transport (Ford and Hasselbach 2001). In a followup study, heavy metal concentrations in moss were measured throughout CAKR (n = 226) and geostatistical models were used to predict the extent and pattern of atmospheric deposition of Cd and Pb on NPS lands (Hasselbach et al 2005). Spatial regression analyses indicated that heavy metal deposition decreased with distance from the haul road and the port site.…”

“…Risks associated with exposure by ingestion tend to be greater in smaller animals because weight-normalized food intake rates tend to increase with decreasing body weights (U.S. Environmental Protection Agency 1993). Areas along the haul road in the northwestern part of CAKR were targeted based on previous studies that indicated that metal deposition within CAKR was greatest along the road and nearest to the port site (Hasselbach et al 2005). Areas north of the haul road are subject to greater contamination from fugitive dusts because of prevailing southerly winds.…”

Atmospheric Deposition and Critical Loads for Nitrogen and Metals in Arctic Alaska: Review and Current Status

“…Tissue concentrations of Pb were previously determined in mosses 1 collected from 24 sites across Arctic Alaska [65]; from multiple 1600-m transects lying perpendicular to a lead-zinc mine haul road and from nearby reference sites [141,142] in Cape Krusenstern National Monument-one of the NPS western Arctic management areas-and finally at Denali National Park and Preserve located in Interior Alaska [107]. Notably, moss samples of the latter study were washed before analysis, but washing was not done with the other studies.…”