Effects of Lead (Pb) from Smelter Operations in an Urban Terrestrial Food Chain at a Colorado Superfund Site

Lead (Pb) is ubiquitous in urban environments, and it is a risk factor for wildlife. But wildlife are particularly at risk for exposure near smelters in urban areas where higher than safe Pb levels in the soil have the potential to transfer to the food chain. Therefore, we investigated whether wildlife are at risk of Pb exposure and differences in Pb bioaccumulation in trophic levels at a Superfund site in an urban area of Colorado. We sampled soil, vegetation, arthropods, and birds at four sites: two contaminated sites (one at the Superfund site and one near the Superfund site) and two reference sites with low predicted Pb contamination. We found significantly higher Pb levels in the soil at the contaminated Slag pile at the Superfund site, compared to the other sites. At the Slag pile, Pb levels were the highest in vegetation and both arthropods and birds accumulated Pb. However, Pb did not increase between trophic levels in the terrestrial food web at the site. We concluded that smelter operations at the Superfund site resulted in significantly higher levels of Pb in the soil and sublethal accumulation in all taxa studied. This research can be used to mitigate the risks to vulnerable wildlife populations exposed to Pb at the Superfund site. Further examination of Pb toxicity in vulnerable taxa is critical to conserving wild populations and ecosystems near contamination zones.