Images

Runoff from this sealcoated lot will flow into the storm drain, where it will be transported to streams and lakes.

In 2009, USGS had a test plot professionally sealed with coal-tar-based sealcoat in preparation for measurements of volatilization from the pavement after application.

In 2009, USGS had a test plot professionally sealed with coal-tar-based sealcoat in preparation for measurements of volatilization from the pavement after application. Here, the applicator applies the sealcoat to the parking lot.

In 2009, USGS had a test plot professionally sealed with coal-tar-based sealcoat in preparation for measurements of volatilization from the pavement after application. Here, the newly applied sealcoat is black and shiny.

In 2009, USGS had a test plot professionally sealed with coal-tar-based sealcoat in preparation for measurements of volatilization from the pavement after application. Here, the applicator checks the tank.

A hydrologic technician uses a meter to measure water-quality parameters, such as pH, dissolved oxygen, and specific conductance, in a domestic-supply well.

Iowa farm in a cornfield in the early morning mist.  USGS research investigates the effects of agricultural use of fertilizers, pesticides, and other chemicals in the quality of surface water and groundwater.

This farm in Iowa sits amid a field of corn.  USGS researches the effects of agricultural use of fertilizers, pesticides, and other chemicals on surface-water and groundwater quality.

The longear sunfish is a freshwater fish in the sunfish family. An increase in sunfish in southeastern streams, intentionally stocked or unintentionally transplanted, has caused the composition of fish species among streams in the Southeast to become more similar. Such homogenization of species is an emerging and pervasive threat to biodiversity.

A USGS water-quality sampling crew sets up to collect a groundwater sample from a public-supply well in South St. Paul, Minnesota, as part of the USGS National Water Quality Assessment (NAWQA) Project.

U.S. Geological Survey (USGS) scientists collecting bed-sediment samples from Suwanee Creek, Gwinnett County, Georgia, on May 23, 2007. 

Sealcoat, marketed to protect and beautify the underlying asphalt, sharply contrasts here with the light gray of unsealcoated asphalt pavement. Read more about coal-tar-based sealcoat and PAHs here.

More than 40 million people in the U.S. rely on domestic wells, like the one shown here, for their drinking water. Concentrations of groundwater at the wellhead typically are low, but lead can leach into the water from corrosion of household plumbing that contains lead.