Modeling & Monitoring of PCBs in Sediments for the Kalamazoo River RI/FS

The Challenge

In order to respond to the requirements of the CERCLA RI/FS process, the KRSG was required to develop a detailed technical understanding of the nature, extent, transport and fate of PCBs in the Kalamazoo River. Development of a cleanup approach required a broad range of services, including field data collection; data management and analysis; and model development, application, and forecasting of remedy effectiveness. All of this work had to be completed under a demanding schedule to meet State and Federal deadlines.

The Solution

LimnoTech was an integral part of the team performing the RI/FS. KRSG and the consultant team worked to assess the extent of contamination and the importance of existing loadings. Due to the complexity of the site and proposed remedies, the team recognized the need for numerical models of PCB fate and transport, as well as bioaccumulation in fish, to evaluate the effectiveness of remedial alternatives.

We developed a suite of modeling tools to provide an analysis of remedial alternatives, including a model of bank erosion, a hydraulic and sediment transport model of the river, and a PCB fate and transport model based on a version of the US EPA WASP model that LimnoTech refined and customized for application to contaminated sediment problems. The models were applied for a 40-year time frame to evaluate the expected effectiveness of different remedy alternatives.

The development of the RI/FS models also helped to identify critical data needs. To address these needs, we also designed and implemented an intensive sediment and water quality monitoring program that involved measurement of sediment resuspension properties, remotely sensed distribution of sediment types and bathymetry, and water quality. Based on our findings, we developed cost-effective remedial alternatives to reduce human and ecological health risks associated with PCB exposure. Our work has served as a basis for decision-making and remedy implementation, which are ongoing at the site.