Oil and Gas Wastewater Exposure Pathways: What We Know and What Remains Unanswered
Produced water is a complex waste byproduct from oil and gas development that can be repurposed for beneficial uses. Understanding its applications, how it moves through the environment, and its potential effects on human health is essential. USGS researchers, in collaboration with Health Effects Institute (HEI) Energy, reviewed and analyzed existing literature to identify knowledge gaps about human exposure risks associated with produced water, synthesizing findings from 236 publications to highlight important areas that need further investigation for safe management and environmental protection.
Produced water, a byproduct of oil and gas extraction, has beneficial reuse options but can pose environmental management challenges. In the U.S., four trillion liters are produced annually, drawing attention to its management and potential uses, especially in water-scarce areas. Treated produced water can be reused in a variety of ways, such as for watering crops, providing drinking water for livestock, and maintaining roads. This repurposing helps save money on waste disposal. Additionally, when produced water is released into streams, it can help raise water levels in these waterways, benefiting local wildlife and recreational activities. Moreover, treating this water can also lead to the extraction of valuable minerals that are essential for various industries. As the push to use produced water expands beyond the oil fields, understanding how people might be exposed becomes increasingly important.
USGS researchers and their Health Effects Institute (HEI) Energy collaborators sought to clarify how people might be exposed to produced water and identify gaps in knowledge. Their review of existing literature analyzed what is known about produced water, the different ways people can be exposed, and the populations potentially at risk. This information aims to guide decisions on using produced water while ensuring public health is protected.
What is produced water?
Produced water is not just ordinary wastewater; it contains a complex mix of chemicals that vary based on the extraction site. It often has high salinity—up to ten times that of seawater—and includes dissolved solids, metals, organic compounds, and potentially hazardous materials. This variability complicates the assessment of human exposure risks and environmental impacts, with uncertainties remaining about its composition and toxicity.
How might people be exposed to produced water?
People can be exposed to produced water in several ways. This exposure may occur through spills or leaks that happen during its handling and management. Additionally, there are authorized releases, such as discharging the water into surface water, using it for crop irrigation, and applying it on roads for maintenance. Produced waters may move through surface- or groundwater, soil, and air, leading to multiple exposure pathways.
Who might be exposed to produced water?
Many studies have found evidence of contamination from produced water in different environments, highlighting the potential for human exposure. However, assessing whether exposures pose a significant health risk is challenging due to uncertainties about the composition of produced water and how its components move, change, and break down under various environmental conditions.
Simplified conceptual model of potential exposure pathways associated with oil and gas development (OGD) produced‐water management summarized in the current study. NPDES is an EPA permit program that regulates discharge of pollutants (https://www.epa.gov/npdes).
From the synthesis of current literature, several important knowledge gaps were identified that would improve the ability to assess human health risk from exposure to produced water, including:
- Analytical Methods: The need for improved techniques to detect and measure chemicals in produced water due to its high salinity and varying composition.
- Environmental Release Documentation: Inadequate records of environmental releases of produced water.
- Treatment Method Performance: Uncertainty about how well different treatment methods work for various intended uses of produced water.
- Tracking Movement through the Environment: Lack of understanding of how produced water components move through the environment and can lead to human exposure.
- Exposed Populations: Insufficient information on the communities that may be at risk of exposure.
This study was supported by the U.S. Geological Survey Ecosystems Mission Area, through the Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology), and the Health Effects Institute, HEI Energy.
To read the publication, "Pathways for Potential Exposure to Onshore Oil and Gas Wastewater: What We Need to Know to Protect Human Health"
USGS Efforts to Address Exposure to Produced Water
USGS Environmental Health-Energy Integrated Science Team scientists are actively addressing knowledge gaps regarding produced water and its potential health risks. Their research efforts prioritize understanding the chemical makeup of produced water, movement through the environment, improving cleanup methods, and supporting safe management of produced water in various regions.
- Chemical Analysis: USGS scientists are analyzing harmful chemicals, such as per- and polyfluoroalkyl substances (PFAS), and commodities such as lithium, in oil and gas produced water to ensure safe reuse, handling, and/or disposal of produced water.
- Pollutant Cleanup: USGS research includes testing new microbes for their effectiveness in cleaning up pollutants.
- Health Risk Measurement: Ongoing assessments focus on health risks from substances in produced water, like arsenic and ammonia, emphasizing their impact on public health.
- Contaminant Migration Studies: Studies in California are focused on how contaminants move through groundwater.
- Groundwater Quality Findings: Recent studies indicate that groundwater quality in oil-field areas is generally good, with natural sources contributing to detected contaminants.
- Illegal Dumping Management: In New Mexico, USGS is identifying sources of illegal dumping of produced water and proppants utilized in hydraulic fracturing to reduce cleanup costs and assess natural recovery processes.
For more information on USGS Environmental Health and related USGS studies on produced water or energy development, please visit the Energy Lifecycle Science website or click below to learn more!
Geochemical Signatures of Oil and Gas Wastewater from an Accidental Release
Amphibians Exposed to Oil and Gas Co-Produced Wastewaters:
Oil and Gas Waters Project
Advancements in Geochemistry and Geomicrobiology
California Oil, Gas, and Groundwater (COGG) Program
Illegal Oil and Gas Wastewater Dumps Disrupts Fragile Desert Ecosystems
Indication of Unconventional Oil and Gas Wastewaters Found in Local Surface Waters
Unlocking Arkansas' Hidden Treasure: USGS Uses Machine Learning
Produced water is a complex waste byproduct from oil and gas development that can be repurposed for beneficial uses. Understanding its applications, how it moves through the environment, and its potential effects on human health is essential. USGS researchers, in collaboration with Health Effects Institute (HEI) Energy, reviewed and analyzed existing literature to identify knowledge gaps about human exposure risks associated with produced water, synthesizing findings from 236 publications to highlight important areas that need further investigation for safe management and environmental protection.
Produced water, a byproduct of oil and gas extraction, has beneficial reuse options but can pose environmental management challenges. In the U.S., four trillion liters are produced annually, drawing attention to its management and potential uses, especially in water-scarce areas. Treated produced water can be reused in a variety of ways, such as for watering crops, providing drinking water for livestock, and maintaining roads. This repurposing helps save money on waste disposal. Additionally, when produced water is released into streams, it can help raise water levels in these waterways, benefiting local wildlife and recreational activities. Moreover, treating this water can also lead to the extraction of valuable minerals that are essential for various industries. As the push to use produced water expands beyond the oil fields, understanding how people might be exposed becomes increasingly important.
USGS researchers and their Health Effects Institute (HEI) Energy collaborators sought to clarify how people might be exposed to produced water and identify gaps in knowledge. Their review of existing literature analyzed what is known about produced water, the different ways people can be exposed, and the populations potentially at risk. This information aims to guide decisions on using produced water while ensuring public health is protected.
What is produced water?
Produced water is not just ordinary wastewater; it contains a complex mix of chemicals that vary based on the extraction site. It often has high salinity—up to ten times that of seawater—and includes dissolved solids, metals, organic compounds, and potentially hazardous materials. This variability complicates the assessment of human exposure risks and environmental impacts, with uncertainties remaining about its composition and toxicity.
How might people be exposed to produced water?
People can be exposed to produced water in several ways. This exposure may occur through spills or leaks that happen during its handling and management. Additionally, there are authorized releases, such as discharging the water into surface water, using it for crop irrigation, and applying it on roads for maintenance. Produced waters may move through surface- or groundwater, soil, and air, leading to multiple exposure pathways.
Who might be exposed to produced water?
Many studies have found evidence of contamination from produced water in different environments, highlighting the potential for human exposure. However, assessing whether exposures pose a significant health risk is challenging due to uncertainties about the composition of produced water and how its components move, change, and break down under various environmental conditions.
Simplified conceptual model of potential exposure pathways associated with oil and gas development (OGD) produced‐water management summarized in the current study. NPDES is an EPA permit program that regulates discharge of pollutants (https://www.epa.gov/npdes).
From the synthesis of current literature, several important knowledge gaps were identified that would improve the ability to assess human health risk from exposure to produced water, including:
- Analytical Methods: The need for improved techniques to detect and measure chemicals in produced water due to its high salinity and varying composition.
- Environmental Release Documentation: Inadequate records of environmental releases of produced water.
- Treatment Method Performance: Uncertainty about how well different treatment methods work for various intended uses of produced water.
- Tracking Movement through the Environment: Lack of understanding of how produced water components move through the environment and can lead to human exposure.
- Exposed Populations: Insufficient information on the communities that may be at risk of exposure.
This study was supported by the U.S. Geological Survey Ecosystems Mission Area, through the Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology), and the Health Effects Institute, HEI Energy.
To read the publication, "Pathways for Potential Exposure to Onshore Oil and Gas Wastewater: What We Need to Know to Protect Human Health"
USGS Efforts to Address Exposure to Produced Water
USGS Environmental Health-Energy Integrated Science Team scientists are actively addressing knowledge gaps regarding produced water and its potential health risks. Their research efforts prioritize understanding the chemical makeup of produced water, movement through the environment, improving cleanup methods, and supporting safe management of produced water in various regions.
- Chemical Analysis: USGS scientists are analyzing harmful chemicals, such as per- and polyfluoroalkyl substances (PFAS), and commodities such as lithium, in oil and gas produced water to ensure safe reuse, handling, and/or disposal of produced water.
- Pollutant Cleanup: USGS research includes testing new microbes for their effectiveness in cleaning up pollutants.
- Health Risk Measurement: Ongoing assessments focus on health risks from substances in produced water, like arsenic and ammonia, emphasizing their impact on public health.
- Contaminant Migration Studies: Studies in California are focused on how contaminants move through groundwater.
- Groundwater Quality Findings: Recent studies indicate that groundwater quality in oil-field areas is generally good, with natural sources contributing to detected contaminants.
- Illegal Dumping Management: In New Mexico, USGS is identifying sources of illegal dumping of produced water and proppants utilized in hydraulic fracturing to reduce cleanup costs and assess natural recovery processes.
For more information on USGS Environmental Health and related USGS studies on produced water or energy development, please visit the Energy Lifecycle Science website or click below to learn more!