A characterization scheme based on landfill leachate chemical signatures could support studies of leachate evolution over time, liner performance, and help confirm or disprove potential leachate contamination of groundwater. Wide variations in single constituents across time, sites, and site practices, and inconsistencies related to common bivariate measures suggest a robust, multivariate analysis could be useful. A variant Stiff diagram approach (a subjective analytical comparison of soluble salts) has been developed, and supports graphical depictions of multiple samples. The hypothesis is that leachates with similar chemistry form clusters, and this was tested using a data set of 652 samples from 26 distinct liner systems collected from a Long Island (New York, USA) landfill over more than 20 years. Most (75%) of diagrams were classified into three general leachate groupings that associated with the kinds of wastes received in the particular landfill module (90% if "early" leachate results are not considered).
Tonjes, David J., "A Classification Methodology for Landfill Leachates" (2013). Technology & Society Faculty Publications. 20.