Date of Award

2018-01-01

Degree Name

Doctor of Philosophy

Department

Environmental Science and Engineering

Advisor(s)

Philip Goodell

Abstract

Regional geochemical mapping constitute the chemistry of the surface of the earth in a large scale and relatively low sample density. It is widely accepted scientific activity and man uses some cases to identify contamination. In the present study, data present in national geochemical survey database was used to investigate the chemical loading loading of the agricultural soil. In the mid-continent region of the United States. Several traditional parameters were used mainly the enrichment factor (EF), and geoaccumulation index (I geo). Total chemical influence (TCI) maps were used to guide sampling. In addition, regional trace element chemistry of bedrock was created and residual geochemical mapping was initiated. The heavy metals selected for this study include As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se, V, and Zn, selected in the basis of toxicity and maximum permitted limit (MPL). Analysis in this study showed that Co, Cu, V, and Zn with high concentrations values (outliers) could be potentially associated with potential anthropogenic applications. Principal Component Analysis (PCA) showed one family has a strong correlation including the elements As, Co, Cr, Ni, and Zn. Maps of loess distribution and glacial encroachment were investigated to test the influence in soil chemistry. Point sourness of chemical emissions were also considered, but except few cases, there were no influences in soil chemical anomalous. The heavy metals in geochemical maps within values 1.4-7.6 investigated anthropogenic outputs from different point sources ranging from moderate to substantially enriched soil EF’s.. It is not evident that air releases contributed to heavy metals in soil chemistry. Surprisingly, the results of generated litheogeochemical maps showed different aspects of soil chemistry. The soil chemistry of these states reflects anthropogenic activities. Considering the spatial variations of soil chemistry, approximately 70% of the soil suffered from overloading of heavy metals. Certain biological properties of the soil were determined to test soil fertility. PO43- is the most abundant nutrient in

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the soil. High values observed in some regions in Midwest of USA implies great chemical inputs by the human rather than natural sources, causing important implications for soil fertility. The results suggest possible long time overloading of fertilizers inputs into the surface soil of agricultural regions n mid-continent of USA.

Language

en

Provenance

Received from ProQuest

File Size

248 pages

File Format

application/pdf

Rights Holder

Najwah Alssaeidi Ahmed Almesleh

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