The full OKI Spring 2023 Newsletter is available for download (click the text link).

PFAS Characterization in Groundwater, Lakes, and Streams

PFAS the ‘forever chemicals’ Per- and polyfluoroalkyl substances (PFASs) are manmade compounds used in a variety of applications such as non-stick cookware, food packaging, and firefighting foam. PFAS have been manufactured since the 1940’s and more than 7,800 PFAS are known to exist. By virtue of their molecular structure and composition, PFAS are bioaccumulative, mobile, persistent, and ubiquitous in the environment.

Exposure to PFAS may result in a wide range of adverse health impacts, but the long-term health and ecological risks are not fully known. In 2016, the U.S. Environmental Protection Agency released Health Advisories (HAs) for two of the commonly detected PFAS, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). The HAs set a lifetime exposure of 70 parts per trillion (ppt) in drinking water. Some states and regional organizations have established additional advisories for PFAS.

The Ohio-Kentucky-Indiana Water Science Center (OKI WSC) has adapted existing USGS sample-collection methods to collect PFAS samples and characterize PFAS distribution in groundwater, lakes, and streams. (Read more in Full Newsletter)

Update on the Illinois River Basin Next Generation Water Observing System and Integrated Water Availability Assessment

The Illinois River Basin (IRB) was the third of ten Integrated Water Science (IWS) basins selected in 2021 to represent watersheds across the Midwestern U.S. that are impacted by excess nutrients and harmful algal blooms (HABs). There are three key components of the IWS studies nationwide. The Next Generation Water Observing System (NGWOS) study brings next generation monitoring tools to better define the nutrient and HABs issues in the IRB. The Integrated Water Availability Assessments (IWAAs) effort in the IRB will use existing models to direct NGWOS monitoring activities, identify data gaps, and make water availability assessments in the IRB. The Integrated Water Prediction will pull the basin information together for predictive modeling of nutrients and HABs in the IRB. Together, these components of the IWS study of the IRB will advance the science of nutrient loads and HABs in Midwestern US basins. (Read more in Full Newsletter)

The Role of Groundwater on Nutrient Mobility and Best Management Practice Success at Great Lakes Restoration Initiative Edge-of-Field Sites

The Great Lakes Restoration Initiative (GLRI) is evaluating best management practices (BMPs) that may reduce the discharge of agrichemicals from surrounding states to the Great Lakes. Agrichemicals may cause multiple deleterious effects, including stimulating harmful algal blooms (HABs) that reduce water availability and limit recreational uses. Tile drains that intercept shallow groundwater are monitored by the USGS at GLRI Edge-of-Field (EOF) sites, but to date, work has not considered the transport and fate of agrichemicals in pore water from the unsaturated zone or deeper groundwater that may be nutrient reservoirs (legacy nutrients) that contribute to tile drains and streams.

Monitoring wells have been installed at three monitoring sites positioned along a regional groundwater flow path to understand shallow and deep groundwater nutrient dynamics between the regional recharge area (glacial moraine) and discharge area (Maumee River). Shallow monitoring wells (<15 ft below ground surface) are instrumented with sensors to measure continuous water level, temperature, and specific conductance. Monthly water-quality sampling for shallow and deep (>15 ft below ground surface) monitoring wells was initiated in the spring of 2022 to understand the temporal variability of nutrients in groundwater. (Read more in Full Newsletter)

Employee Spotlights

Employee spotlights in this edition include Shawn Naylor (Hydrologist), Chad Toussant (Physical Scientist), David Kidd (Hydrologic technician), Les Arihood (50 years with the USGS), Clyde Jefferson Sholar (In Memoriam), and Scott Edwin Morlock (In Memoriam).