Statistical evaluation of geochemical parameter distribution in a ground water system contaminated with petroleum hydrocarbons.

A shallow-depth ground water area was investigated to identify the dominant processes governing the distribution of hydrocarbon contaminants and hydrogeochemical parameters. The ground water in the study site has been highly contaminated with petroleum hydrocarbons. A preliminary pump-and-treatment remediation technology was applied for 4 yr at the site. Multivariate analyses were applied to hydrogeochemical data obtained before and after the rainy season. The pump-and-treatment application, indigenous biodegradation, and mixing by precipitation recharge are the major factors or events involved in the distribution of geochemical parameters of the ground water in the study area. Site-specific artificial pavement also played an important role in the evolution of the ground water chemistry. A conventional graphical analysis method (Piper plot) of major ions did not effectively reveal these effects. In this study, we demonstrate the usefulness of multivariate analysis (factor and cluster analyses) using biodegradation indicator parameters, as well as major cations and anions, for the study of the ground water system in the hydrocarbon-contaminated site.