WASTEWATER CONTAMINANTS AS TRACERS OF HYDROLOGIC PROCESSES

Rapid developments in liquid chromatography coupled with mass spectrometry (LC-MS) have allowed for low femto-mole detection of many polar and amphiphilic compounds found in high concentrations (0.1 – 100 nM) in municipal and industrial wastewater effluents. Special attention is presently being paid to pharmaceuticals, disinfectants, surfactants, disinfection by-products and natural and synthetic endocrine disrupters that are either produced or not efficiently removed in conventional municipal wastewater treatment. To date, most work has focused on analytical detection and environmental occurrence. However, due to the large analytical dynamic range and properties of specific wastewater contaminants, they can serve as valuable and perhaps unique tracers of hydrologic transport and several hydrologic processes. Presented in this paper will be selected examples of how wastewater contaminants can be used as conservative tracers of wastewaters (x-ray contrasting agents and anti-seizure drugs); particle tracers (selected surfactants and disinfectants); measures of direct and indirect photolysis (fluorescent whitening agents); and tracers of the efficiency of microbially mediated sewage treatment processes (alkyl phenol ethoxylates and other parent-metabolite compositions). To illustrate recent progress in analytical approaches to the study of wastewater contaminants, applications of LC-time-of-flight mass spectrometry (TOF-MS) will be presented. Specifically, LC-TOF-MS provides both high sensitivity and accurate mass calculation of target analytes and of unknown transformation products.