Occurrence of viruses and unregulated contaminants in Iowa public water supply groundwater

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Project Period: 
Collaborating Institution(s): 
Iowa Department of Natural Resources, U.S. Geological Survey
UI Department of Geosciences, U.S. Department of Agriculture
Project Investigator(s): 
Robert Libra, Iowa Geological and Water Survey
Michael Wichman, State Hygienic Laboratory

Groundwater supplies drinking water to about 80% of Iowa’s population; most Iowans obtain water from public water supplies (PWS), which are required by EPA to monitor finished water for various chemical, physical, and biological contaminants; raw source water monitoring is infrequently required. EPA publishes a Drinking Water Contaminant Candidate List detailing contaminants that may require standards and monitoring in the future. A strategy to assess future drinking water regulatory needs, and to guide source water protection activities for both public and domestic wells is targeted sampling and analysis of raw PWS groundwater for currently unregulated contaminants with public health and environmental concerns. This project will sample 66 Iowa PWS wells with known construction and hydrogeologic vulnerability for a number of contaminants. Funding for this project comes from EPA and Iowa DNR Drinking Water and Source-Water Protection programs. CHEEC funds will be used for sampling and analysis of PWS wells for human enteric viruses. The upcoming federal Unregulated Contaminant Monitoring Rule will have an emphasis on groundwater contaminants; this project will complement the national plan and establish Iowa as a leader in monitoring groundwater quality for contaminants with public health implications.

Project Results: 

The work directly measured the quality of public water supply groundwater used by Iowans. It provides a baseline of contaminant occurrence and concentrations, allowing for challenges to current supplies and treatment systems to be realized in a timely manner. It also raised awareness of these unregulated contaminants with state agencies and water supply operators.

The study's key findings include:

  1. Pharmaceuticals commonly detected at trace levels.
  2. Human viruses present, and possibly more common during wetter periods?
  3. No obvious analytical indicators of virus occurrence.
  4.  Wastewater constituents, either pharmaceuticals and/or viruses, present almost 60% of raw public supplygroundwater.
  5. A long-standing Iowa Geological Survey groundwater vulnerability methodology works relatively well for these emerging contaminants.