Objectives:The major objective of the proposed work is to determine the horizontal, vertical and temporal distributions of total dissolved organic carbon (DOC) and ca class of trace contaminants, the polycyclic aromatic hydrocarbons (PAH), real-time in Boston Harbor. Sources such as river discharge, atmospheric deposition, sewage outfall, and benthic fluxes will be examined for relative strengths to help predict the future water quality in Boston Harbor. A long-term objective of this work is development of a fiber optic fluorometry system for multiple chemical sensors allowing simultaneous measurement of several environmental parameters and specific contaminants to aid in assessing the status of coastal waters.Methodology:A time resolved fiber optic based spectrofluorometry system will be used to detect these two classes of compounds simultaneously in situ. A CTD sensor system and global positioning system (GPS) will help place horizontal, vertical and temporal organic measurements in a physical and geochemical perspective. In addition, discrete samples will be taken in order to ground truth the real time measurements by using a laboratory spectrofluorometer, solvent extraction, and gas chromatography (GC) and gas chromatography/mass spectrometry (GCMS).Rationale:High spatial and temporal resolution is needed to map plume geometries and distributions of non point source contaminants. Time resolved spectrofluorometry is a technique that can be applied real time, in situ, for measurement of DOC and PAH. These measurements in conjunction with tradition compound specific analyses will allow better assessment of contaminants in urban harbors and coastal waters.