Implementation of a geographic information system in the chemistry curriculum: an exercise in integrating environmental analysis and assessment

Abstract

The rate of nonlinear sediment deposition in a local pond was determined through the application of Geographic Information System (GIS) software to an established laboratory method. Determination of total sediment deposition is difficult to solve using a single method as a result of the high degree of spatial variability. The spatial analysis tools available in the software, such as interpolation and overlay operations, provides a mechanism to interpolate sediment accumulation at distinct sampling points. The depth of sediment accumulated at individual sample locations was related to the lead content as determined by atomic absorption spectrometry (AAS). As a result of the discontinuation of leaded gasoline in 1970, a decline in lead emissions has occurred, with a corresponding peak in lead concentrations evident in collected sediments. This makes lead a useful tracer to determine sediment deposition since 1970. ArcView 3.2 was employed to integrate sample site locations obtained from the Global Positioning System (GPS), features digitized from aerial photographs, tabular values of lead concentrations from the AAS analysis, and depth data collected by sounding sample sites. After integrating this information the software could then generate graphic representations of sediment deposition throughout a local pond over a thirty-year timeframe. The data obtained suggest sediment accumulation between 10 and 75 cm at different sites throughout the study area and an estimated total accumulation of over 1900 m3 of sediment since 1970.