Preliminary Investigation of the Potential for River Sediment Transport of PCBs from the Horton Iron & Metal NPL Site to areas within a 3.9 mile Cape Fear River Study Area near Wilmington, NC

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Title: Preliminary Investigation of the Potential for River Sediment Transport of PCBs from the Horton Iron & Metal NPL Site to areas within a 3.9 mile Cape Fear River Study Area near Wilmington, NC
Author: Daniel, Shawna
Abstract: Abstract Daniel, Shawna. Master of Environmental Assessment. Preliminary Investigation of the Potential for River Sediment Transport of PCBs from the Horton Iron & Metal NPL Site to areas within a 3.9 mile Cape Fear River Study Area near Wilmington, NC. A preliminary investigation of polychlorinated biphenyl (PCB) congener concentrations in the Cape Fear River near the Horton Iron & Metal National Priorities List (NPL) site was conducted in the spring of 2014; both sediment and water samples were collected for chemical analysis. The investigation was prompted by previous studies which indicated the presence of PCBs, polycyclic aromatic hydrocarbons (PAHs), semi-volatile organic compounds (SVOCs), volatile organic compounds (VOCs), and several metals in the sediments of the boat slips associated with the NPL site, as well as the presence of PCBs and metals in the sediments and water of the nearby Cape Fear Community College (CFCC) boat operations basin. PCB congeners were detected throughout the 3.9 mile stretch of the Cape Fear River that comprised the study area with PCB congeners 206 and 209 being both the most prevalent (detected in 9 of the 20 sediment samples) and in the highest per-sample concentrations. Of the 21 PCB congeners tested for in the samples, 11 congeners were detected (IUPAC 52, 101, 105, 118, 128, 138, 153, 180, 187, 206, and 209) with individual congener concentrations ranging from 0 to 15.77 ng/g in single sediment sample analysis. Maximum concentrations for the two most prevalent PCBs, 206 and 209, were found in sediment samples from the Horton boat slips (15.77 ng/g and 5.10 ng/g, respectively). Maximum summed PCB concentrations (ΣPCBs) for individual sediment samples were found to be 29.64 ng/g at a sample site located approximately 1250 feet from the Horton site, 22.72 ng/g at the Horton site, and 28.87 ng/g at the CFCC operations basin. Maximum ΣPCBs for individual water samples were found to be 3.91 ng/g in the CFCC basin (PCBs 105, 138, and 153). Concentrations of individual PCB congeners 52, 101, 187, 206, and 209 do appear to show a possible gradient effect in the sediments between the Horton basin and CFCC basin that may be indicative of PCB transportation; sample size for this study was too small to definitively delineate such a gradient. With PCB concentrations exceeding current no-risk thresholds (3.6×10-6 to 14 ng/g for total PCBs in sediment, dry weight), potential for adverse human and environmental health effects may be a concern at this site. This study warrants further investigation to examine the extent and distribution of PCB contamination as well as the existence of other contaminants with the potential to elicit adverse environmental effects.
Date: 2014-12
URI: http://www.lib.ncsu.edu/resolver/1840.4/8565


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