Geological Society of America

26 Metal Pollution in the Eastern Midcontinent and Beyond

Friday, 8 April 2022
8:00 AM - 12:00 PM
North Meeting Room 206

LEAD SPECIATION, BIOACCESSIBILITY AND SOURCE ATTRIBUTION IN MISSOURI’S BIG RIVER WATERSHED

Paper number: 26-2
Program: Theme Sessions
Time: 8:05 AM – 8:20 AM

Authors

Matthew Noerpel Presenting Author
Office of Research and Development, Cincinnati, OH
Michael J. Pribil
U.S. Geological Survey, Denver, CO
Danny Rutherford
U.S. Geological Survey, Denver, CO
Preston Law
Region 7, Kansas City, KS
Karen Bradham
U.S. Environmental Protection Agency, Raleigh, NC
Clay Nelson
Office of Research and Development, Cincinnati, OH
Rob Weber
Region 7, Kansas City, KS
Gene Gunn
Region 7, Kansas City, KS
Kirk G. Scheckel
U.S. Environmental Protection Agency, Cincinnati, OH

Abstract

The Southeast Missouri Lead District is among the most productive lead deposits exploited in modern times. Intensive mining conducted prior to regulations resulted in a legacy of lead contaminated soil, large piles of mine tailings and elevated childhood blood lead levels. This study sought to identify the source of the lead contamination in the Big River and inform risk to the public. Isotopic analysis indicated the mine tailing piles at the head of the Big River are the primary source of the lead contamination. The isotopic signature of the lead in these mine tailings matched the lead in the stream bed and in the flood plain for over 100 km downstream. All of the other potential lead sources investigated had different isotopic signatures. Lead concentrations in soils and sediments decrease with distance downstream of the mine tailings piles. Additionally, the speciation of the lead changes from predominantly mineralized forms, such as galena, to adsorbed lead. This is reflected in the in-vitro bioaccessibility assay (IVBA) analysis which shows higher bioaccessibility further downstream, demonstrating the importance of speciation and bioaccessibility in risk evaluation.

Geological Society of America Abstracts with Programs. Vol. 54, No. 4

doi: 10.1130/abs/2022NC-374713

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