Use of reclaimed water and stormwater for wetland restoration on a municipal wellfield: evaluating potential impacts to public health
The Section 21 Wellfield is located in northwest Hillsborough County, Florida. Wetlands and lakes within the wellfield have been impacted by historic wellfield pumping-related activities and local land development activities. The Section 21 Wellfield Restoration Project is a multi-agency effort designed to assess whether surface water and/or reclaimed water are viable water sources for wetland restoration. As part of this project, a Risk Assessment was performed to address public health concerns associated with the potential application of reclaimed water and surface water to wetlands located on the wellfield. Work performed in support of the Risk Assessment included background and source water quality sampling and a detailed field characterization of the subsurface geology, hydrogeology, and aquifer transport characteristics. Hydrologic models were developed to determine the potential travel times of the source waters from land surface to production wells and the relative contributions of source waters to pumped waters. The modeling results were utilized to perform a human health risk assessment, following EPA guidance and other published documents, to evaluate the potential risk associated with the proposed application of reclaimed or surface water to wetlands. The risk assessment results indicate no risks to human health due to a chemical exposure. Microbiological risks due to ingestion of drinking water would be comparable to less than background. Use of reclaimed water/storm/surface water for wetland restoration presents varying risk profiles for recreational activities as compared to the background risk with respect to microbiological constituents.