The quality of our Nation's waters: water quality in the Northern Atlantic Coastal Plain surficial aquifer system, Delaware, Maryland, New Jersey, New York, North Carolina, and Virginia, 1988-2009

The surficial aquifer system of the Northern Atlantic Coastal Plain is made up of unconfined aquifers that underlie most of the area. This aquifer system is a critical renewable source of drinking water and is the source of most flow to streams and of recharge to underlying confined aquifers. Millions of people rely on the surficial aquifer system for public and domestic water supply, in particular in the densely populated areas of Long Island, New York, and in southern New Jersey, but also in more rural areas. Because the aquifer sediments are permeable and the water table is shallow, the surficial aquifer system is vulnerable to contamination from chemicals that are applied to the land surface and carried into groundwater with infiltrating rainfall and snowfall.

Major Findings

• The quality of most groundwater produced for public and domestic water supply is suitable for drinking, although contaminants at concentrations greater than human-health benchmarks have been detected in some places
• Nitrate is one of the most widespread contaminants in groundwater
• Radium occurs commonly in groundwater as a result of the degradation of uranium and thorium minerals naturally present in aquifer sediments
• Chemicals in groundwater move slowly and can be detected in the environment for several decades after they enter the surficial aquifer system