ANALYSIS OF POSSIBLE ANTHROPOGENIC IMPACT IN SURFACE WATER QUALITY IN EASTERN MASSACHUSETTS

Using our data and data from the USGS National Water Quality Assessment (NAWQA) Program for New England streams, we present a characterization of current state of surface water, changes in time and dependence on land use, precipitation regime, and possible other natural and human influences. Time series analysis is used to detect changes and relationship with discharge and precipitation regime. Statistical techniques are employed to analyze relationships among multiple chemical variable monitored. Analysis of ion concentrations reveals information about possible natural sources and processes, and anthropogenic influences. A notable example is the increase in salt concentration in ground and surface waters, with impact on drinking water quality. Salt concentration increase in water can be linked to road salt usage during winters with heavy snowfall and other factors. Another example, is suggested by magnesium concentrations anomaly in Saugus River. The concentration of Mg was found less than 5 mg/L in most rivers, except in Saugus, where the measured concentrations were mainly higher than 5 mg/L. Also, Ca-Mg data are typically highly correlated in all streams but are uncorrelated in water samples from Saugus River. This anomaly, corroborated with the fact that Saugus was the site of the Saugus Iron Works (~1647-1669), led to further investigation. Magnesium oxide is often used as a lining for furnaces. The use of MgO in furnace bricks at the site and disposal of used bricks in the vicinity of the sampling site for Saugus River water samples might be a source of enhanced Mg in samples that were collected at this site. While this effect is small, the purpose of this study is to illustrate the value of NAWQA data, statistical analysis and GIS to address water quality issues and improve our understanding of relationship between human activities and environment.