Study Highlights the Complexity of Chemical Mixtures in United States Streams Completed
Collecting Water-Quality Samples from the Enoree River, SC
Processing Water-Quality Samples Collected from the Enoree River, SC
A new study highlights the complexity of chemical mixtures in streams and advances the understanding of wildlife and human exposure to complex chemical mixtures.
Chemical contaminants do not occur alone in our water resources and detections of complex chemical mixtures are commonly documented in rivers and streams across the United States. Fish and other wildlife are exposed to these complex mixtures of chemicals. There is also the potential for human exposure through direct skin absorption, ingestion of contaminated drinking water, or consumption of contaminated wildlife.
This study builds on previous work that identified mixtures of contaminants in streams across the United States. The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (EPA) collaborated to assess more than 700 organic chemicals as well as indicators of biological effects in 38 streams within the United States, which represented one of the most comprehensive set of contaminants ever monitored at individual stream sites. This study was an opportunity to assess the factors related to site-to-site differences in stream-contaminant complexity and to put the chemical data into context with potential effects on aquatic animal health.
The results indicate that the mixtures of chemicals in streams reflect combined contaminant contributions originating from a combination of agricultural, industrial, municipal, and residential sources in individual watersheds. Complex chemical mixtures (a range of 4 to 161 chemicals per stream) were detected in streams across a range of urban and agricultural areas in the United States. As expected, fewer chemicals were detected in the 4 streams that had low population density compared to the 34 urban/agricultural-influenced locations.
Indicators of biological activity, such as estrogen receptor activation, were present in all stream samples except for one reference site. Estrogenicity activity values have yet to be firmly established; however, multiple sites exceeded activity levels estimated to signal potential adverse effects on aquatic organisms. The indicators were related to target chemicals in the water samples to different degrees, which advanced our understanding of exposure and relative risk of specific chemicals and mixtures.
The results of this overall effort yield insights into the complexity of chemical mixtures present in a wide range of surface waters across the United States and their potential for eliciting adverse ecological health consequences. These results are important to answer questions about minimizing health risks and economic costs, if any, associated with mixed-contaminant exposures.
The USGS Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology), the EPA Safe and Sustainable Water Resources, and the Chemical Safety for Sustainability Research Programs funded this study.
Related research is listed below.
Drinking Water and Wastewater Infrastructure Science Team
Food Resources Lifecycle Integrated Science Team
Sources of Contaminants to Congaree National Park—USGS and National Park Service Working Together
Recovery of Stream and Adjacent Groundwater After Wastewater Treatment Facility Closure
Chemical Mixtures and Environmental Effects
Long-Term Study Finds Endocrine Disrupting Chemicals in Urban Waterways
Assessing Environmental Chemical Mixtures in United States Streams
Chemical Combo and Intersex Fish Found at Smallmouth Bass Nesting Sites
Complex Mixture of Contaminants Persists in Streams Miles from the Source
- Overview
A new study highlights the complexity of chemical mixtures in streams and advances the understanding of wildlife and human exposure to complex chemical mixtures.
Chemical contaminants do not occur alone in our water resources and detections of complex chemical mixtures are commonly documented in rivers and streams across the United States. Fish and other wildlife are exposed to these complex mixtures of chemicals. There is also the potential for human exposure through direct skin absorption, ingestion of contaminated drinking water, or consumption of contaminated wildlife.
Sources/Usage: Public Domain. View Media DetailsUSGS scientist collecting water-quality samples from the Enoree River, SC This study builds on previous work that identified mixtures of contaminants in streams across the United States. The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (EPA) collaborated to assess more than 700 organic chemicals as well as indicators of biological effects in 38 streams within the United States, which represented one of the most comprehensive set of contaminants ever monitored at individual stream sites. This study was an opportunity to assess the factors related to site-to-site differences in stream-contaminant complexity and to put the chemical data into context with potential effects on aquatic animal health.
Sources/Usage: Public Domain. View Media DetailsUSGS scientist processing water-quality samples. She is surrounded by lots of equipment The results indicate that the mixtures of chemicals in streams reflect combined contaminant contributions originating from a combination of agricultural, industrial, municipal, and residential sources in individual watersheds. Complex chemical mixtures (a range of 4 to 161 chemicals per stream) were detected in streams across a range of urban and agricultural areas in the United States. As expected, fewer chemicals were detected in the 4 streams that had low population density compared to the 34 urban/agricultural-influenced locations.
Indicators of biological activity, such as estrogen receptor activation, were present in all stream samples except for one reference site. Estrogenicity activity values have yet to be firmly established; however, multiple sites exceeded activity levels estimated to signal potential adverse effects on aquatic organisms. The indicators were related to target chemicals in the water samples to different degrees, which advanced our understanding of exposure and relative risk of specific chemicals and mixtures.
The results of this overall effort yield insights into the complexity of chemical mixtures present in a wide range of surface waters across the United States and their potential for eliciting adverse ecological health consequences. These results are important to answer questions about minimizing health risks and economic costs, if any, associated with mixed-contaminant exposures.
The USGS Environmental Health Program (Toxic Substances Hydrology and Contaminant Biology), the EPA Safe and Sustainable Water Resources, and the Chemical Safety for Sustainability Research Programs funded this study.
- Science
Related research is listed below.
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.Food Resources Lifecycle Integrated Science Team
The team studies the movement of toxicants and pathogens that could originate from the growing, raising, and processing/manufacturing of plant and animal products through the environment where exposure can occur. This information is used to understand if there are adverse effects upon exposure and to develop decision tools to protect 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.Recovery of Stream and Adjacent Groundwater After Wastewater Treatment Facility Closure
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.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.Long-Term Study Finds Endocrine Disrupting Chemicals in Urban Waterways
U.S. Geological Survey (USGS) scientists determined that endocrine disrupting chemicals (EDCs) were present in wastewater treatment plant (WWTP) effluent, water, and fish tissue in urban waterways in the Great Lakes and upper Mississippi River Regions (Indiana, Illinois, Michigan, Minnesota, and Ohio) during 1999 through 2009.Assessing Environmental Chemical Mixtures in United States Streams
The U.S. Geological Survey (USGS) and the U.S. Environmental Protection Agency (EPA) are collaborating on a field-based study of chemical mixture composition and environmental effects in stream waters affected by a wide range of human activities and contaminant sources.Chemical Combo and Intersex Fish Found at Smallmouth Bass Nesting Sites
Chemical contaminants including herbicides, veterinary pharmaceuticals, and biogenic hormones have been detected at fish nesting sites in the Potomac River watershed where endocrine disruption in smallmouth bass ( Micropterus dolomieu ) was also observed. Although these contaminants are known to originate from a variety of human and animal-waste sources, results of a recent U.S. Geological Survey...Complex Mixture of Contaminants Persists in Streams Miles from the Source
Natural processes in stream ecosystems such as dilution and microbial degradation are known to attenuate some contaminants to below levels that can cause harm to ecosystems. However, a team of U.S. Geological Survey (USGS) scientists has shown that many chemicals discharged from municipal wastewater treatment facilities persist for miles downstream at levels known, or suspected, to cause adverse... - Data
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