ASSESSING THE DISTRIBUTION OF MGP RESIDUALS IN CAYADUTTA CREEK SEDIMENTS – MATCHING THE TOOLS TO THE SITE

摘要

When tasked with delineating the nature and extent of Manufactured Gas Plant (MGP) constituents in an aquatic system, there are a number of characterization tools and sampling techniques available to a site or project manager. Our premise is that the development of a conceptual site model is an essential first step towards identification and implementation of a cost-effective characterization program. At an MGP site in Upstate New York, the presence of coal tar non-aqueous phase liquids (NAPL) was suspected in an adjacent creek as a result of surface water runoff and groundwater discharge from the site. The New York State Department of Environmental Conservation (NYSDEC) requested that the extent of MGP-related constituents in the creek be determined, and data be collected for use in a feasibility study for the site. Existing information along with historical and current observations were used to develop a conceptual site model. With this initial understanding of site dynamics established, we were better able to develop a phased characterization program for the site. The characterization program included site reconnaissance, probing and mapping, and a targeted sediment and bank soil sampling program designed to assess polynuclear aromatic hydrocarbon (PAH) extent, mobility, and source identification for use in the Remedial Investigation and Feasibility Study (RI/FS) process. Using the Cayadutta Creek as a case study, we will demonstrate the value of establishing a conceptual site model at the onset of an investigation, and the utility of a number of sediment characterization techniques.