Stormwater runoff from a portion of a 273 ha ͑675 acres͒ Midwestern rail yard contacts industrial facilities including fuel storage tanks and fueling and servicing operation areas. Stormwater draining from a smaller 64 ha ͑159 acres͒ sub-basin containing the industrial facilities previously flowed into a retention pond within the rail yard. The retention pond had a surface area of 607 m 2 ͑0.15 acre͒ and a maximum storage capacity of 1.4 million L ͑370,000 gal͒. Given the large drainage area of the pond the retention time within the pond was shorter than optimal, limiting its potential effectiveness for improving water quality. To address these issues the pond was redesigned to have a 6.25 million L ͑1.65 million gal͒ storage capacity and configured into a constructed wetland to control a 50-year storm event and increase its ability to treat stormwater runoff. A network of riparian plants ͑5,700͒ was placed within the stormwater wetland to treat runoff prior to discharge off-site. Evaluating the performance of both the former and current retention basins revealed significant improvements in the retention and treatment ability when comparing the two structures. Mean total suspended solid concentrations and oil and grease concentrations were reduced approximately 45% when comparing pre-and postconstruction flow analysis. This innovative multiuse approach has demonstrated effectiveness in controlling storm flows and treating runoff from the rail yard.

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Although vapor monitoring is generally a component of remedial action activities, most sites do not have routine gaseous releases or vapor clouds erupting from the soil during implementation of the cleanup process (or during cleanup of the site). At the North Carolina State University Lot 86 National Priorities List Site, over 8410 m 3 (11,000 yd 3 ) of chemical waste was disposed at the Site, including organic solvents and shock-sensitive and airand water-reactive compounds. During the Remedial Action, it was imperative to protect site workers and off-site populations from potential inhalation exposures. Engineering controls were incorporated into the shallow soil mixing process to limit the release of gaseous compounds. To quantify potential exposures to on-site and off-site receptors, modeling was conducted to evaluate potential exposure routes and migration pathways. To demonstrate acceptable levels of airborne constituents, a multifaceted air sampling and monitoring program was implemented. To ensure that potential exposures could be quantified, passive dosimeters, continuous real-time monitoring, time-weighted whole air sampling, and grab samples of vapor clouds were all critical components of the air monitoring program. After the successful completion of the Remedial Action, the pre-Resource Conservation and Recovery Act (RCRA) chemical waste generated from the University's educational and research laboratories was entirely encapsulated and neither on-site workers nor offsite populations were exposed to analyzed compounds above any health-based action level (i.e., 15-min shortterm exposure limit [STEL], 8-hr threshold limit value, or time-weighted average permissible exposure limit).