278 Understanding Temporal Dynamics in Hydrogeochemistry and Sedimentary Processes in Estuarine Environments

This session explores temporal changes in estuarine environments with respect to water chemistry and sediment inputs. Effects of evolving physiochemical properties and isotopic composition of water, as well as the geochemical attributes of sediments on the environment will be presented.

Wednesday, 22 October 2025
1:30 PM - 5:30 PM
HBGCC, 213AB

Analysis and sources of Heavy Metal Contaminants in Waterbodies in Mills and Fremont Counties in Iowa

Paper number: 278-2
Program: Technical Sessions
Time: 1:55 PM – 2:10 PM

Authors

Abstract

After our previous study (Spring 2024) took a broad look at Nebraska, Iowa, and Missouri, this study focus is on a smaller geographic area: Fremont and Mills County in southwest Iowa, as well as Cass and Sarpy County in southeast Nebraska. The goal of this study is to confirm the contaminant level and gain a better understanding of the water quality across southwest Iowa as well as identifying any possible effects from recent flooding. Water samples were collected using plastic sampling jars from various water bodies around Mills and Fremont counties in southwest Iowa. These samples were analyzed using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) machine. Additional measurements including alkalinity, nitrate, anions, conductivity, and others using testing strips were undertaken. Within this area, the analyzed water samples from different water bodies (river, lake, pond, stream) helped determine and confirm that the 2024 concentration levels of heavy metals (As, Al, Cd, Co, Cr, Cu, Fe, Ni, Pb, Zn) have changed when compared with the US-EPA standard. The analytical calibration curves plotted, the linearity of data, and value of correlation coefficients for each toxic and essential metal shows that most of the Fe and Al concentrations are still far above the EPA threshold limit ((Fe = 295.94µg/L) and (Al = 308.22 µg/L)) whereas, Co, Cr, Cu, Ni, Pb, and Zn are below the threshold limit in the selected counties. Furthermore, As, Cd, and Pb concentrations in the water bodies (creek, lake, and pond) in Iowa were confirmed to be slightly high above the EPA threshold and this conforms with our previous study (Spring, 2024). The source of metals in the counties were most likely mobi­lized through weathering of the porous slag soil material and long distance mine transport. Future work will adequately evaluate the potential for distance off-site pollution contamination, ground and surface water, lake sediment, and metal uptake in aquatic vegetation and fisheries will be evaluated as well to discuss the health effects.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-411911

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