_{² Exponent
1730 Rode Island Ave., NW
Washington, DC  20036
Phone (202) 441-6484  Fax (703) 834-2707}

Most evaluations of the contribution of different sources to environmental contamination at different locations begin with a set of measurements of chemical species at different locations. One then calculates either a variance-covariance or correlation matrix and performs some type of factor analysis. The resulting multivariate patterns shown in the factor solution are then used to identify the contribution of different sources to contamination and proportion the cleanup cost. The present discussion takes a different approach that derives from the Bayesian analysis of genetic data to determine the likely paternity of a given child given a set of data from potential fathers, the mother and the child. We demonstrate the use of two variants this approach. One assumes independence of chemical contaminant production while the other considers the specific multi-contaminant production. In both we begin with a non-informative prior that assumes that all sources are equally likely to have contributed to the site contamination and use the data to calculate a posterior probability of each source being responsible for the contamination.

In: McRoberts, R. et al. (eds).  Proceedings of the joint meeting of The 6th International Symposium On Spatial Accuracy Assessment In Natural Resources and Environmental Sciences and The 15th Annual Conference of The International Environmetrics Society, June 28 – July 1 2004, Portland, Maine, USA.