U.S. Geological Survey Scientists Complete First Systematic Regional Survey of Algal Toxins in Streams of the Southeastern United States Completed
USGS Scientist Collecting Periphyton Samples
USGS Scientists Collecting Microcystin Samples from Enoree River, SC
U.S. Geological Survey (USGS) scientists detected microcystin—an algal toxin—in 39 percent of 75 streams assessed in the southeastern United States. These results will inform and become part of a larger, systematic national survey of algal toxins in small streams of the United States.
Cyanobacteria are photosynthetic microorganisms that are present in streams, lakes, wetlands, and oceans worldwide. Cyanobacteria are known to intermittently produce toxins (cyanotoxins) that can have adverse effects on a wide range of organisms including bacteria, algae, insects, plants, bivalves, fish, and humans, but the factors that trigger toxin production are not well understood. Microcystins are among the most commonly reported and widely studied cyanotoxins, and concerns are growing due to apparent increases in the frequency and severity of human and ecological health effects.
As a first step toward designing a survey to advance our understanding of microcystin occurrence in small streams, USGS scientists utilized historical periphyton data (1993–2011) and identified cyanobacteria including Leptolyngbya, Phormidium, Pseudoanabaena, and Anabaena species) in 74 percent of headwater streams in Alabama, Georgia, South Carolina, and North Carolina during this time period. Although microcystins were not measured during that initial research, the presence of microcystin producing cyanobacteria provided critical evidence that enabled the scientists to prioritize and design subsequent research.
With that evidence in hand, USGS scientists then collected environmental samples from 75 targeted streams with varying urban and agricultural land use in the southeastern United States for microcystin analyses. Five sites representative of a land use gradient were resampled monthly in August, September, and October 2014 to provide additional insight into the persistence and temporal variability of microcystin occurrence within the study area. Overall, microcystins were detected in 39 percent of the streams with median detected concentrations of 0.29 micrograms per liter (µg/L) and a maximum concentration of 3.2 µg/L.
Although none of the microcystin concentrations exceeded the World Health Organization moderate risk threshold of 10 µg/L, this study is the first of several regional assessments of algal toxins, (including the Pacific Northwest, the northeastern U.S., and California) being planned and conducted now. Together, these studies will provide important baseline data across the United States to understand and document the extent, magnitude, and sources of algal toxins in the environment.
Environmental Health Considerations
The environmental health significance and causal factors controlling the distribution and magnitude of microcystin occurrence remains poorly understood. Baseline data from these regional studies are being used to inform new research designed to improve those understandings and will be focused on investigations of land use and other factors that may affect or create new environmental pathways of exposure to cyanobacteria and associated toxins.
This research was funded by the USGS Ecosystems Mission Area’s Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology) and the USGS National Water-Quality Assessment Program (NAWQA).
Related research is listed below.
Toxins and Harmful Algal Blooms Science Team
USGS Scientist Receives Award for Assistance with National Wetlands Assessment
Nutrients in Dust from the Sahara Desert cause Microbial Blooms on the East Coast of the United States
USGS Scientists Measure New Bacterial Nitrogen Removal Process in Groundwater
Cyanobacterial (Blue-Green Algal) Blooms: Tastes, Odors, and Toxins
New Study on Cyanotoxins in Lakes and Reservoirs Provides Insights into Assessing Health Risks
Importance of Lake Sediments in Removal of Cyanobacteria, Viruses, and Dissolved Organic Carbon
Remote Sensing Provides a National View of Cyanobacteria Blooms
Algal Blooms Consistently Produce Complex Mixtures of Cyanotoxins and Co-Occur with Taste-and-Odor Causing Compounds in 23 Midwestern Lakes
Below are publications associated with this research.
Spatial and temporal variation in microcystins occurrence in wadeable streams in the southeastern USA
Field and laboratory guide to freshwater cyanobacteria harmful algal blooms for Native American and Alaska Native communities
Microphotographs of cyanobacteria documenting the effects of various cell-lysis techniques
Harmful algal blooms
Below are data or web applications associated with this project.
Regional Stream Quality Assessment (RSQA)
The Regional Stream Quality Assessment (RSQA), part of the National Water Quality Assessment project, seeks to characterize multiple water-quality factors that are stressors to aquatic life (contaminants, nutrients, sediment, and streamflow alteration) and to develop a better understanding of the relation of these stressors to ecological conditions in streams throughout the region.
Below are news stories associated with this project.
- Overview
U.S. Geological Survey (USGS) scientists detected microcystin—an algal toxin—in 39 percent of 75 streams assessed in the southeastern United States. These results will inform and become part of a larger, systematic national survey of algal toxins in small streams of the United States.
Cyanobacteria are photosynthetic microorganisms that are present in streams, lakes, wetlands, and oceans worldwide. Cyanobacteria are known to intermittently produce toxins (cyanotoxins) that can have adverse effects on a wide range of organisms including bacteria, algae, insects, plants, bivalves, fish, and humans, but the factors that trigger toxin production are not well understood. Microcystins are among the most commonly reported and widely studied cyanotoxins, and concerns are growing due to apparent increases in the frequency and severity of human and ecological health effects.
As a first step toward designing a survey to advance our understanding of microcystin occurrence in small streams, USGS scientists utilized historical periphyton data (1993–2011) and identified cyanobacteria including Leptolyngbya, Phormidium, Pseudoanabaena, and Anabaena species) in 74 percent of headwater streams in Alabama, Georgia, South Carolina, and North Carolina during this time period. Although microcystins were not measured during that initial research, the presence of microcystin producing cyanobacteria provided critical evidence that enabled the scientists to prioritize and design subsequent research.
With that evidence in hand, USGS scientists then collected environmental samples from 75 targeted streams with varying urban and agricultural land use in the southeastern United States for microcystin analyses. Five sites representative of a land use gradient were resampled monthly in August, September, and October 2014 to provide additional insight into the persistence and temporal variability of microcystin occurrence within the study area. Overall, microcystins were detected in 39 percent of the streams with median detected concentrations of 0.29 micrograms per liter (µg/L) and a maximum concentration of 3.2 µg/L.
Although none of the microcystin concentrations exceeded the World Health Organization moderate risk threshold of 10 µg/L, this study is the first of several regional assessments of algal toxins, (including the Pacific Northwest, the northeastern U.S., and California) being planned and conducted now. Together, these studies will provide important baseline data across the United States to understand and document the extent, magnitude, and sources of algal toxins in the environment.
Environmental Health Considerations
The environmental health significance and causal factors controlling the distribution and magnitude of microcystin occurrence remains poorly understood. Baseline data from these regional studies are being used to inform new research designed to improve those understandings and will be focused on investigations of land use and other factors that may affect or create new environmental pathways of exposure to cyanobacteria and associated toxins.
This research was funded by the USGS Ecosystems Mission Area’s Environmental Health Program (Contaminant Biology and Toxic Substances Hydrology) and the USGS National Water-Quality Assessment Program (NAWQA).
- Science
Related research is listed below.
Toxins and Harmful Algal Blooms Science Team
The team develops advanced methods to study factors driving algal toxin production, how and where wildlife or humans are exposed to toxins, and ecotoxicology. That information is used to develop decision tools to understand if toxin exposure leads to adverse health effects in order to protect human and wildlife health.USGS Scientist Receives Award for Assistance with National Wetlands Assessment
U.S. Geological Survey (USGS) scientist Dr. Keith A. Loftin received the U.S. Environmental Protection Agency (EPA) Office of Water's Achievement in Science and Technology Award for his contributions to the National Wetlands Condition Assessment.Nutrients in Dust from the Sahara Desert cause Microbial Blooms on the East Coast of the United States
Saharan dust nutrients, particularly iron, deposited episodically in tropical marine waters stimulate marine microbial bloom growth and change microbial community structure.USGS Scientists Measure New Bacterial Nitrogen Removal Process in Groundwater
For the first time, U.S. Geological Survey (USGS), Virginia Institute of Marine Science, and the University of Connecticut scientists have detected active anammox bacteria in groundwater.Cyanobacterial (Blue-Green Algal) Blooms: Tastes, Odors, and Toxins
Freshwater and marine harmful algal blooms (HABs) can occur anytime water use is impaired due to excessive accumulations of algae. In freshwater, the majority of HABs are caused by cyanobacteria (also called blue-green algae). Cyanobacteria cause a multitude of water-quality concerns, including the potential to produce taste-and-odor causing compounds and toxins that are potent enough to poison...New Study on Cyanotoxins in Lakes and Reservoirs Provides Insights into Assessing Health Risks
Newly published study provides new evidence of the widespread occurrence of cyanotoxins in lakes and reservoirs of the United States and offers new insights into measures used for assessing potential recreational health risks.Importance of Lake Sediments in Removal of Cyanobacteria, Viruses, and Dissolved Organic Carbon
U.S. Geological Survey (USGS) scientists determined that the colmation layer (top 25 centimeters of lake sediments) was highly effective in removing cyanobacteria, viruses, and dissolved organic carbon during water passage through the lake bottom to aquifer sediments.Remote Sensing Provides a National View of Cyanobacteria Blooms
Four Federal agencies, including the U.S. Geological Survey (USGS), are collaborating to transform satellite data into information managers can use to protect ecological and human health from freshwater contaminated by harmful algal blooms.Algal Blooms Consistently Produce Complex Mixtures of Cyanotoxins and Co-Occur with Taste-and-Odor Causing Compounds in 23 Midwestern Lakes
U.S. Geological Survey (USGS) scientists studying the effects of harmful algal blooms on lake water quality found that blooms of blue-green algae (cyanobacteria) in Midwestern lakes produced mixtures of cyanotoxins and taste-and-odor causing compounds, which co-occurred in lake water samples. Cyanotoxins can cause allergic and/or respiratory issues, attack the liver and kidneys, or affect the... - Publications
Below are publications associated with this research.
Spatial and temporal variation in microcystins occurrence in wadeable streams in the southeastern USA
Despite historical observations of potential microcystin-producing cyanobacteria (including Leptolyngbya,Phormidium, Pseudoanabaena, and Anabaena species) in 74% of headwater streams in Alabama, Georgia, South Carolina, and North Carolina (USA) from 1993 to 2011, fluvial cyanotoxin occurrence has not been systematically assessed in the southeastern United States. To begin to address this data gap,AuthorsKeith A. Loftin, Jimmy M. Clark, Celeste A. Journey, Dana W. Kolpin, Peter C. Van Metre, Paul M. BradleyField and laboratory guide to freshwater cyanobacteria harmful algal blooms for Native American and Alaska Native communities
Cyanobacteria can produce toxins and form harmful algal blooms. The Native American and Alaska Native communities that are dependent on subsistence fishing have an increased risk of exposure to these cyanotoxins. It is important to recognize the presence of an algal bloom in a waterbody and to distinguish a potentially toxic harmful algal bloom from a non-toxic bloom. This guide provides field imaAuthorsBarry H. Rosen, Ann St. AmandMicrophotographs of cyanobacteria documenting the effects of various cell-lysis techniques
Cyanotoxins are a group of organic compounds biosynthesized intracellularly by many species of cyanobacteria found in surface water. The United States Environmental Protection Agency has listed cyanotoxins on the Safe Drinking Water Act's Contaminant Candidate List 3 for consideration for future regulation to protect public health. Cyanotoxins also pose a risk to humans and other organisms in a vaAuthorsBarry H. Rosen, Keith A. Loftin, Christopher E. Smith, Rachael F. Lane, Susan P. KeydelHarmful algal blooms
What are Harmful Algal Blooms (HABs)? Freshwater and marine harmful algal blooms (HABs) can occur anytime water use is impaired due to excessive accumulations of algae. HAB occurrence is affected by a complex set of physical, chemical, biological, hydrological, and meteorological conditions making it difficult to isolate specific causative environmental factors. Potential impairments include reduAuthorsJennifer L. Graham - Web Tools
Below are data or web applications associated with this project.
Regional Stream Quality Assessment (RSQA)
The Regional Stream Quality Assessment (RSQA), part of the National Water Quality Assessment project, seeks to characterize multiple water-quality factors that are stressors to aquatic life (contaminants, nutrients, sediment, and streamflow alteration) and to develop a better understanding of the relation of these stressors to ecological conditions in streams throughout the region.
- News
Below are news stories associated with this project.