MAGNESIUM TO CALCIUM CONCENTRATION RATIO DISHARMONY OF THE SAUGUS RIVER, BOSTON, MA

For most New England Rivers, the Magnesium to Calcium concentration ratio varies independently from Magnesium and Calcium concentrations. However, this is not true for the Saugus River. The Magnesium to Calcium concentration ratio of the Saugus River appears to be dependent on the Magnesium concentration. The objective of this study is to determine why this is observed for the Saugus River, but not for the other New England Rivers. Possible causes include sea spray, industrial contamination, and upstream cation exchange reactions.

For this study, we use a robust dataset consisting of Magnesium and Calcium concentration records collected by the USGS from nine New England Rivers. Eight of these rivers, the Kennebec River, Merrimack River, Charles River, Aberjona River, Ipswich River, Stillwater River, Wading River, and Neponset River, display the typical Magnesium and Calcium concentration behavior described above. However, the Magnesium and Calcium concentration behavior of the Saugus River is markedly different. The magnitude of change over time in the Magnesium to Calcium concentration ratio of the Saugus River is similar to the magnitude of change over time observed for the other rivers. But the Magnesium to Calcium concentration ratio is not independent of Magnesium and Calcium concentrations, as is observed for the other rivers. Longitudinal profiles of Magnesium and Calcium concentrations of the Saugus River were created to assist in determining the source of the observed discrepancy.