Pre-Columbian lead pollution from Native American galena processing and land use in the midcontinental United States

Abstract

The presence and sources of pre-Columbian (before 1492 CE) lead (Pb) pollution in the midcontinental United States were investigated using geochemical and Pb isotope analyses on sediment cores recovered from Avery Lake, a floodplain lake located directly adjacent to the Kincaid Mounds archaeological site on the lower Ohio River, Illinois. Geochemical results indicate the presence of Pb pollution during the Baumer (300 BCE to 300 CE) and Mississippian (1150–1450 CE) occupations, and since the 1800s. Pb isotope results link Mississippian Pb pollution to the processing and use of galena primarily from southeastern and/or central Missouri, and to a lesser extent the upper Mississippi River valley, with ∼1.5 t (metric tons) of galena-derived Pb deposited in Avery Lake during this time. Pb pollution during the Baumer phase, equating to ∼0.4 t of Pb, was not accompanied by a Pb isotope excursion and most likely originated from local biomass burning. These results provide new information about the environmental impacts associated with pre-Columbian Native Americans’ interaction with and utilization of their landscape and its resources.

High variability between regional histories of long-term atmospheric Pb pollution

“…In North America, there is little evidence of pre-European use of base metals 50 , so low levels of anthropogenic Pb pollution prior to this point is to be expected. A small increase during the Mississippian period (1150-1450 CE) in the North American synthesis may be observed, reflective of limited pre-Colombian pollution on the continent 51,52 , represented by a low-probability changepoint from 1100 CE onwards (Fig. 2C).…”

Lead pollution can be detected in North America for thousands of years

“…In this issue of Geology, a groundbreaking paper by Bird et al (2019b) uses Pb stable isotopes and a mixing model at Avery Lake to determine the specific mineral source of the Pb pollution. (Bird et al, 2019b).…”

“…In this issue of Geology, a groundbreaking paper by Bird et al (2019b) uses Pb stable isotopes and a mixing model at Avery Lake to determine the specific mineral source of the Pb pollution. (Bird et al, 2019b). Therefore, Pb pollution at Kincaid was likely galena powder that was washed or blown into Avery Lake (Bird et al, 2019b).…”

“…(Bird et al, 2019b). Therefore, Pb pollution at Kincaid was likely galena powder that was washed or blown into Avery Lake (Bird et al, 2019b). The Pb isotope mixing model approach taken by Bird et al (2019b) demonstrates that it is possible to estimate both the source and amount of Pb pollution derived from the long, mostly unknown, tradition of metal use in North America.…”

“…Therefore, Pb pollution at Kincaid was likely galena powder that was washed or blown into Avery Lake (Bird et al, 2019b). The Pb isotope mixing model approach taken by Bird et al (2019b) demonstrates that it is possible to estimate both the source and amount of Pb pollution derived from the long, mostly unknown, tradition of metal use in North America. Future research using Pb isotopes and sediments recovered near archaeological sites will likely reveal more information regarding the sources, spatial pattern, and duration of pre-Columbian Pb pollution in North America.…”