United States Geological Survey

About: United States Geological Survey is a government organization based out in Reston, Virginia, United States. It is known for research contribution in the topics: Population & Groundwater. The organization has 17899 authors who have published 51097 publications receiving 2479125 citations. The organization is also known as: USGS & US Geological Survey.

Pesticides in the Nation's Streams and Ground Water, 1992-2001

Abstract: Water samples collected from 1992 through 2001 from 186 streams and rivers and from 5,047 wells in 51 of the nation's major river basins and aquifer systems were summarized to provide the most comprehensive national-scale analysis of pesticide occurrence to date. At least one pesticide was detected in water from all streams studied, and at least one pesticide was detected more than 90 percent of the time in water from streams draining agricultural, urban, or mixed land uses. Pesticides were less common in groundwater than in streams, but were detected in more than 50 percent of the sampled shallow wells beneath agricultural and urban areas. About one-third of the deeper wells sampled, which tap major aquifers used for water supply, contained one or more pesticides or pesticide degradates.

Urban Sprawl Leaves Its PAH Signature

Abstract: The increasing vehicle traffic associated with urban sprawl in the United States is frequently linked to degradation of air quality, but its effect on aquatic sediment is less well-recognized. This...

Vulnerability of high-latitude soil organic carbon in North America to disturbance

Abstract: [1] This synthesis addresses the vulnerability of the North American high‐latitude soil organic carbon (SOC) pool to climate change Disturbances caused by climate warming in arctic, subarctic, and boreal environments can result in significant redistribution of C among major reservoirs with potential global impacts We divide the current northern high‐latitude SOC pools into (1) near‐surface soils where SOC is affected by seasonal freeze‐thaw processes and changes in moisture status, and (2) deeper permafrost and peatland strata down to several tens of meters depth where SOC is usually not affected by short‐term changes We address key factors (permafrost, vegetation, hydrology, paleoenvironmental history) and processes (C input, storage, decomposition, and output) responsible for the formation of the large high‐latitude SOC pool in North America and highlight how climate‐related disturbances could alter this pool’s character and size Press disturbances of relatively slow but persistent nature such as top‐down thawing of permafrost, and changes in hydrology, microbiological communities, pedological processes, and vegetation types, as well as pulse disturbances of relatively rapid and local nature such as wildfires and thermokarst, could substantially impact SOC stocks Ongoing climate warming in the North American high‐latitude region could result in crossing environmental thresholds, thereby accelerating press disturbances and increasingly triggering pulse disturbances and eventually affecting the C source/sink net character of northern high‐latitude soils Finally, we assess postdisturbance feedbacks, models, and predictions for the northern high‐latitude SOC pool, and discuss data and research gaps to be addressed by future research