The paper reports some of the re sults of an evaluation of the utility of the J.W. Criss fundamental parameters computer program for environmental assessment samples in which only one standard per element was used an d where the standard matrix did not strictly resemble the unknown matrix. In general, the fundamental program, involving the application of x-ray fluorescence and diffraction, proved to be quite capable of yielding meaningful results. Relative errors ranged from 2 to 20% for a variety of sample types. This accuracy was obtained using only one readily available pure compound (usually a simple inorganic oxide) as a standard per element determined. The advantage of this approach to a laboratory that receives a variety of unique samples is apparent. Additionally, the computer search of powder diffraction data of environmental samples was shown to contribute to the speciation of the complex samples that are encountered in environmental assessments.