Date of Award

1-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Earth and Environmental Studies

Thesis Sponsor/Dissertation Chair/Project Chair

Duke Ophori

Committee Member

Clement Alo

Committee Member

Huan Feng

Abstract

Regression analyses of major ion concentration, and specific conductance were compared on a decadal basis from field data of the 1960s, 1980s, 1990s, 2000s, and 2010s to find if there is a statistically significant increase in calcium, chloride, and sodium compared to other major groundwater ions in the Middle and Lower Passaic River Basins. Time series graphical analyses, bivariate coefficient relationships, statistical prediction interval evaluations, and multivariate analyses were used to determine the significance of the individual ion concentration trends. Through ArcGIS, bedrock geochemistry was examined in correlation with well locations, ion concentrations, and road placements. GIS was used to create groundwater flow maps using previously collected hydraulic head measurements.

Time series analyses for the Middle Passaic River Basin indicated that sodium and chloride levels are increasing at different rates throughout the study period. Bivariate plots showed no significant correlation between chloride and sodium nor between chloride and total dissolved solids. Piper diagrams indicate that the groundwater species in this region showed little to no change throughout time. These observations indicate that sodium and chloride show only slight to moderate increases from the 1960s to 2010s in the Middle Passaic River Basin groundwater. The combination of low deicing application, low-porosity basalt, gneiss, and granite bedrock, and the presence of large water reservoirs were considered the responsible variables for the low levels of observable contamination in the Middle Passaic River Basin.

Comparatively, ion concentrations for sodium, chloride, as well as calcium (a component of the less common deicing material liquid calcium chloride) increased at substantially greater rates in the Lower Passaic River Basin. Overall, calcium, sodium, chloride, and total dissolved solids increased at significant rates. Sodium against chloride and calcium against chloride bivariate analyses showed strong correlations. This suggests that there is an observable relationship between the ions individually produced via NaCl and CaCl2. Additionally, calcium and sodium show no correlation with one another, suggesting no intermolecular relationship between the two deicing agents. Through multivariate analyses, a shift in groundwater ionic composition from freshwater to salt water was observed in the Lower Passaic River Basin within the study timeframe. These observations indicate that deicing application in the Lower Passaic River Basin has contaminated the underlying groundwater. The high urbanization, road density, and porous bedrock are considered the responsible variables for this outcome.

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