Seminars and Events at the Center
Scott W. Ator
Hydrologist
U.S Geological Survey, MD-DE-DC Water Science Center
Date: Tuesday, June 2, 2009
Time: 11:00
Sources, Fate, and Transport of Pesticides and Nutrients in Streams and Groundwater of the Northern Atlantic Coastal Plain
Abstract
The Northern Atlantic Coastal Plain is an ideal setting for studying interacting natural and human influences on the occurrence, fate, and transport of anthropogenic chemicals in water resources. Climate in the Coastal Plain is humid and groundwater generally occurs within a few meters of the land surface. Sediments comprising the surficial aquifer are permeable and well weathered in many places, and natural groundwater is typically dilute. Most groundwater travels along relatively short flowpaths to discharge areas in local streams; residence times vary from less than a month to more than a century, but are generally less than a few decades. The U.S. Geological Survey, in cooperation with numerous other research groups, has studied nutrients and pesticides in streams and groundwater of the Coastal Plain at local and regional scales for several decades. The occurrence and distribution of these compounds in groundwater depends on the distribution of sources and hydrogeologic and geochemical conditions along flowpaths that control fate and transport. Streams of the Coastal Plain receive a majority of their flow from groundwater discharge, and stream chemistry reflects an integration of such influences from contributing watersheds. Observed temporal trends in groundwater and streams of the Coastal Plain reflect variable land-use practices and chemical applications over recent decades.
