Pollution (Chemical and Biological)

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.

Mercury is a potent neurotoxin that can affect the human nervous system. Eating fish contaminated with mercury can cause serious harm to people and wildlife.

The USGS works to monitor and assess how disease-causing pathogens enter our water and help those who manage drinking and wastewater facilities prevent and treat these viruses, bacteria, algal toxins, and other microorganisms.

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.

Corrosivity describes how aggressive water is at corroding pipes and fixtures. Corrosive water can cause lead and copper in pipes to leach into drinking water and can eventually cause leaks in plumbing. Surface water and groundwater, both sources of drinking water, can potentially be corrosive.

Are you among the more than 100 million people in the U.S. who relies on a public-supply well for your drinking water? Although the quality of finished drinking water from public water systems is regulated by the EPA, long-term protection and management of the raw groundwater tapped by public-supply wells requires an understanding of the occurrence of contaminants in this invisible, vital resource...

More than 43 million people—about 15 percent of the U.S. population—rely on domestic (private) wells as their source of drinking water. The quality and safety of water from domestic wells are not regulated by the Federal Safe Drinking Water Act or, in most cases, by state laws. Instead, individual homeowners are responsible for maintaining their domestic well systems and for monitoring water...

As settlers traveled west and mined the American landscape, thousands of new mines were created over the centuries and then abandoned. Now, these long forgotten remnants of a bygone area still haunt us, as their operations left behind materials and rock exposures that can be easily eroded and carried downstream. The USGS helps track the sources of acidic mine drainage and helps land managers...

Many people might be surprised to learn that drinking-water sources, especially groundwater, can contain radioactive elements (radionuclides). Radionuclides in water can be a concern for human health because several are toxic or carcinogenic. Other radionuclides are useful tools for determining the age of groundwater in an aquifer or of sediment deposited at the bottom of a water body.

People love to play in water. The USGS works to ensure that water in our nation’s streams, lakes, and oceans are suitable for the moments when you just need to jump in.

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.

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.