Author

Milejczak

Date of Award

12-1989

Degree Name

Master of Arts

Department

Geological and Environmental Sciences

Department

Geosciences

First Advisor

Dr. Alan E. Kehew

Second Advisor

Dr. Richard Passero

Access Setting

Masters Thesis-Open Access

Abstract

The Michigan Department of Public Health (MDPH) sampled 149 residential wells producing from glacial drift and Saginaw Formation aquifers in Bay, Midland, Saginaw, and Tuscola counties in 1987. These wells were analyzed for 226Ra, 228Ra and general chemistry. Of the 149 samples, 50 exceeded the USEPA MCL of 5 pCi/L or greater for combined 226Ra + 228Ra activities. A geochemical model (WATEQF, Plummer et al., 1976) was used to determine activity coefficients, activities, ionic strength, and mineral saturation. The radium isotopes were statistically analyzed with respect to the chemical data from MDPH and the geochemical model output. The analysis included the Pearson "r" correlation analysis, linear regression analysis of X-Y plots , and R- Mode factor analysis. 226Ra and 228Ra are positively correlated (r = .89) and may be in equilibrium. Also, radium concentrations correlate positively with Na+, Ca2+, K+, Sr2+, and Cl-. Analysis of bedrock cores from Saginaw Formation cores showed 226Ra, Al2O3, Na2O, CaO, and K2O to be elevated in samples of shale relative to sandstone. The source of radium and the oxides appears to be insoluble clay minerals in the Saginaw Formation. If this is the case, elevated radium, Al3+ , Na+ , Ca2+ , and K+ ions in the bedrock and drift aquifers may be derived from deeper strata.

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Geology Commons

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