Recovery of Stream and Adjacent Groundwater After Wastewater Treatment Facility Closure Completed
A Map of Fourmile Creek Study Area in Ankeny, Iowa
The hydrology and chemistry of a wastewater-impacted stream and adjacent groundwater responded rapidly (had fewer chemicals at lower concentrations) following wastewater treatment facility shutdown. However, the adjacent shallow groundwater remained a continuing source of some wastewater-derived contaminants to the stream at least 1 year post-shutdown.
Contamination of stream water and adjacent groundwater in wastewater-impacted streams is a concern due to the presence of chemicals including pharmaceuticals in wastewater treatment facility (WWTF) effluent that are mobile in the environment and are specifically designed to be bioactive. In this study, scientists had the unique opportunity to assess hydrologic and chemical recovery processes in a stream and adjacent surficial groundwater system following WWTF closure. A combined pre/post-closure assessment (2012–14) was conducted near a long-term WWTF on Fourmile Creek in Ankeny, Iowa. Water samples were collected and water levels monitored continuously in the stream and adjacent groundwater located upstream and downstream from the WWTF outfall. Water samples were analyzed for 110 organic chemicals including 107 human-use pharmaceuticals and degradates.
The hydrology and chemistry of the stream and shallow groundwater system responded rapidly to the WWTF shutdown. There was a nearly instantaneous decrease in water levels of surface-water and groundwater, and immediate elimination of the characteristic, diurnal wastewater-discharge pattern. The number of chemicals detected and cumulative concentrations decreased in Fourmile Creek and the adjacent groundwater. Although the numbers and concentrations of detected chemicals were substantially higher in surface water than in the adjacent groundwater system prior to closure, the reverse was true following WWTF closure. This finding is consistent with the adjacent shallow groundwater system acting as a continuing source of wastewater-derived contaminants to the stream for at least a year after WWTF closure. The persistence of wastewater-derived contaminants in adjacent groundwater suggests the potential for the shallow groundwater system to serve as a long-term source of wastewater-derived contaminants to the stream. Improved understanding of the environmental fate and transport of wastewater-derived contaminants is essential for understanding organism exposure and ecosystem recovery.
This study is funded by the U.S. Geological Survey (USGS) Ecosystem Mission Area's Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology)
See below for other science related to this research.
Drinking Water and Wastewater Infrastructure Science Team
Sources of Contaminants to Congaree National Park—USGS and National Park Service Working Together
Study Highlights the Complexity of Chemical Mixtures in United States Streams
Contaminants of Emerging Concern in the Environment
Chemical Mixtures and Environmental Effects
- Overview
The hydrology and chemistry of a wastewater-impacted stream and adjacent groundwater responded rapidly (had fewer chemicals at lower concentrations) following wastewater treatment facility shutdown. However, the adjacent shallow groundwater remained a continuing source of some wastewater-derived contaminants to the stream at least 1 year post-shutdown.
Sources/Usage: Some content may have restrictions. View Media DetailsA map of Fourmile Creek study area in Ankeny, Iowa, showing the locations of shallow groundwater piezometers, stream water sampling locations, and the direction of flow in the stream. Solid and dashed red arrows indicate the flow direction of the effluent from the wastewater treatment facility. Figure 1 from Bradley and others, 2016. Aerial photo credit: ArcGIS basemap, ESRI. Contamination of stream water and adjacent groundwater in wastewater-impacted streams is a concern due to the presence of chemicals including pharmaceuticals in wastewater treatment facility (WWTF) effluent that are mobile in the environment and are specifically designed to be bioactive. In this study, scientists had the unique opportunity to assess hydrologic and chemical recovery processes in a stream and adjacent surficial groundwater system following WWTF closure. A combined pre/post-closure assessment (2012–14) was conducted near a long-term WWTF on Fourmile Creek in Ankeny, Iowa. Water samples were collected and water levels monitored continuously in the stream and adjacent groundwater located upstream and downstream from the WWTF outfall. Water samples were analyzed for 110 organic chemicals including 107 human-use pharmaceuticals and degradates.
The hydrology and chemistry of the stream and shallow groundwater system responded rapidly to the WWTF shutdown. There was a nearly instantaneous decrease in water levels of surface-water and groundwater, and immediate elimination of the characteristic, diurnal wastewater-discharge pattern. The number of chemicals detected and cumulative concentrations decreased in Fourmile Creek and the adjacent groundwater. Although the numbers and concentrations of detected chemicals were substantially higher in surface water than in the adjacent groundwater system prior to closure, the reverse was true following WWTF closure. This finding is consistent with the adjacent shallow groundwater system acting as a continuing source of wastewater-derived contaminants to the stream for at least a year after WWTF closure. The persistence of wastewater-derived contaminants in adjacent groundwater suggests the potential for the shallow groundwater system to serve as a long-term source of wastewater-derived contaminants to the stream. Improved understanding of the environmental fate and transport of wastewater-derived contaminants is essential for understanding organism exposure and ecosystem recovery.
Sources/Usage: Public Domain. View Media DetailsBefore and after photos of Fourmile Creek near Ankeny, Iowa, showing a wastewater outfall from a wastewater treatment facility (WWTF). The top photo is the creek before the WWTF was closed, and the bottom photo is after the WWTF was shutdown. After the shutdown flow in the creek decreased significantly. Photo credits: Laura E. Hubbard, USGS, Layout by David W. Morganwalp, USGS. This study is funded by the U.S. Geological Survey (USGS) Ecosystem Mission Area's Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology)
- Science
See below for other science related to this research.
Drinking Water and Wastewater Infrastructure Science Team
The team studies toxicants and pathogens in water resources from their sources, through watersheds, aquifers, and infrastructure to human and wildlife exposures. That information is used to develop decision tools that protect human and wildlife health.Sources of Contaminants to Congaree National Park—USGS and National Park Service Working Together
A National Park Service (NPS) and U.S. Geological Survey (USGS) study determined the concentrations, potential for degradation, and potential for aquatic and terrestrial animal exposure to organic contaminants in water and sediment within the flood-plain/aquatic environments of Congaree National Park which is located downstream from urban and agricultural areas.Study Highlights the Complexity of Chemical Mixtures in United States Streams
A new study highlights the complexity of chemical mixtures in streams and advances the understanding of wildlife and human exposure to complex chemical mixtures.Contaminants of Emerging Concern in the Environment
The USGS is conducting source-to-receptor research on a broad range of chemical and microbial contaminants including pharmaceuticals, personal care products, pathogens, antibiotic resistant genes, and natural toxins that are not commonly considered in environmental research but have the potential to impact environmental health.Chemical Mixtures and Environmental Effects
The USGS is investigating the occurrence and environmental effects of complex mixtures of both natural and man-made chemicals in environmental waters. - Publications