Ecosystem Health

Sealcoat is the black, viscous liquid applied to many asphalt parking lots, driveways, and playgrounds in North America to protect and enhance the appearance of the underlying asphalt. Coal-tar-based pavement sealcoat is a potent source of polycyclic aromatic hydrocarbon (PAH) contamination in urban and suburban areas and a potential concern for human health and aquatic life.

Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.

Metals, metalloids, and radionuclides all are trace elements that occur naturally in the Earth's crust. In small quantities many trace elements are essential for health in all living organisms, but some trace elements can be toxic or cause cancer, and some can bioaccumulate. The USGS investigates where and how trace elements make their way into our Nation's surface water and groundwater.

Humans, just like aquatic organisms, need water. Flood control, urban infrastructure, irrigation of agriculture, and myriad other ways we manage water affect the natural flow of streams and rivers. How do the ways we manage land and water affect the natural patterns of streamflow that ecosystems depend on?

The sources, biogeochemistry, and ecotoxicology of selenium (Se) combine to produce a widespread potential for ecological risk such as deformities in birds and fish. Linking the understanding of source characteristics to a mechanistic, biodynamic dietary model of Se exposure on an ecosystem-scale improves the prediction of Se effects and its potential remediation.

Regional groundwater availability studies enable information about groundwater to be integrated and consistent, so that this resource can be analyzed and understood on an aquifer–wide scale. These studies provide decision–makers with a better understanding of the status and trends in the Nation's groundwater availability.

The clams Potamocorbula amurensis and Corbicula fluminea were collected at a variety of sites in the San Francisco Bay/ Delta beginning July 1990 and ending February 2010. These invasive species were used as biosentinels of the fate, transport, and effects of trace metals in the San Francisco Bay ecosystem.

The goals of the Regional Stream Quality Assessment (RSQA) are 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.

The USGS is undertaking a 3-year study of water availability and use to investigate competing societal and ecological needs in Southeastern Atlantic Coastal Basins of the Carolinas. This study will compile existing information, add new scientific data and interpretation, and develop tools to help resource managers and stakeholders address current and future water-use challenges.

The USGS is undertaking a 3-year study of water use, availability, and change in the Red River basin, which covers more than 93,000 square miles in New Mexico, Texas, Oklahoma, Arkansas, and Louisiana. Water resources are being stressed by increasing water demands and increasingly severe droughts, and a comprehensive water-resource assessment of the basin is needed to enable sustainable water use.

USGS is undertaking a 3-year study of water use, availability, and change in the Upper Rio Grande Basin. This study area runs 670 miles from its headwaters in Colorado through New Mexico and northern Mexico to Texas, and will compile existing information and add new scientific data and interpretation to help stakeholders face current and future water issues.

Research by the USGS National Water Quality Assessment (NAWQA) Project on water quality of rivers and streams covers a broad range of topics, from nonpoint pollution issues to vulnerability of aquatic ecosystems. Dive in and find out more about current water-quality conditions, how and where water quality is changing, and the latest information on pesticides, nutrients, and other contaminants.