Long-Term Monitoring
The Lower Fox River PCB Cleanup Project is in the monitored recovery phase. The project will remain in this phase until fish, water and sediment evaluations indicate that the remedial action objectives have been met, which often takes many years following remedial activities. In addition to tracking progress toward those objectives, monitoring is also conducted to ensure the integrity of the engineered caps.
This page provides an overview of the condition of fish, water, sediment and caps in the project area as of the most recent monitoring event (completed in 2022). Please see the Records of Decisions and Long-term Monitoring Plans in the "Technical Documents" section of the Fox River Project Documents page for specifics about the remedial action objectives and requirements to cease monitoring.
The next monitoring event will be in 2027.
Fish Summary
One of the main remedial goals of the Lower Fox PCB Cleanup Project was to lower the risk of PCB exposure through fish consumption. To track progress toward this goal, fish tissue samples are routinely collected from each of the Operational Units (OUs) to ensure PCB concentrations are declining. The primary fish species sampled as part of the long-term monitoring as a consumption indicator is walleye. Smallmouth bass may also be used as a human health risk due to consumption indicator species. Since the remediation was completed in the various OUs, fish tissue PCB concentrations have significantly declined (see the Long-term Monitoring Summary reports on the documents page for details). For the most up-to-date fish consumption advisory, please see the information on the Wisconsin Department of Natural Resources's (DNR) Eating Your Catch page.
In addition to human health-related fish monitoring, monitoring is required to ensure the fish exposure to PCBs is decreasing in the environment. Carp and gizzard shad are the primary fish species used to demonstrate declines in exposure in the environment.
In 2024, the Environmental Protection Agency (EPA) and the DNR approved the termination of continued monitoring for the carp (ecological index) in all the OUs and gizzard shad (young of the year forage) in OU1 and OU4. This monitoring was terminated because the data demonstrated that the conditions to cease monitoring of these fish species in those OUs were met. See the ecological index letter and young of the year letter on the documents page for more information. All other fish categories will be sampled again in 2027.
Water Summary
Water samples are collected in all the OUs to ensure that the PCB concentrations in water are declining. As of the 2022 Long-term Monitoring Summary Report (see Technical Documents section), all the OUs have shown large reductions in PCB concentrations within the water, with some OUs demonstrating over 80% reductions in PCB surface water concentrations. Surface water PCB levels will be monitored again in 2027.
Sediment Summary
Sediment quality is only monitored in the Monitored Natural Recovery areas (OU2 and OU5). Sediment sampling is not required in the other OUs, as active remedial actions were taken in those OUs and those actions met the construction requirements. See the Cleanup Operations and Document sections for more details.
Sediment samples were taken in OU5 in 2021 and OU2 in 2022. Surficial sediment samples show that the PCB concentrations are lower than those collected prior to remediation in 1989/1990. This suggests natural recovery of surface sediments is occurring in these stretches of the river.
Cap Monitoring And Maintenance
Engineered caps require long-term monitoring and maintenance by the responsible parties with oversight by the government. Cap monitoring and maintenance are done following approved plans, including the Cap Monitoring and Maintenance Plan for OU1 and the Cap Operations, Maintenance and Monitoring Plan for OUs 2-5. Cap monitoring and maintenance events take place after the installation of caps and continue thereafter regularly in perpetuity. If cap damage is identified at any time, responsible parties must perform maintenance and repair work with approval and oversight by the agencies. The Cap Monitoring and Maintenance Plan and Cap Operations, Maintenance and Monitoring Plan Reports explain the results of each monitoring event. Plan documents and monitoring reports can be found on the documents page.
Detailed Schedule Review
Long-term monitoring takes place in each OU after cleanup operations are complete. Baseline data refers to samples taken in 2006 and 2007 in each OU. Prior to 2022, the OUs were on different monitoring event schedules due to when remedial actions were completed in the OUs. Starting in 2022, all OUs will be sampled in one event and then every five years thereafter to be on the same monitoring schedule throughout the system and to coordinate with the EPA's 5-Year Review cycle for this project.
For a detailed review of future and past monitoring efforts, please see the long-term monitoring schedule.