Publications

At a “clean air” trade winds site in northeastern Puerto Rico, we found an apparent paradox: atmospheric total mercury (THg) deposition was highest of any site in the USA Mercury Deposition Network, but assimilation into the local food web was quite low. Avian blood THg concentrations (n = 31, from eight species in five foraging guilds) ranged widely from 0.2 to 32 ng g−1 (median of 4.3...

Concentration-discharge relationships are a key tool for understanding the sourcing and transport of material from watersheds to fluvial networks. Storm events in particular provide insight into variability in the sources of solutes and sediment within watersheds, and the hydrologic pathways that connect hillslope to stream channel. Here we examine high-frequency sensor-based specific...

We present a continent-scale exploration of trends in annual 7-day low streamflows at 2482 U.S. Geological Survey streamgages across the conterminous United States over the past 100, 75, and 50 years (1916–2015, 1941–2015 and 1966–2015). We used basin characteristics to identify subsets of study basins representative of reference basins with streamflow relatively free from human effects...

Land use/land cover (LULC) change has significant impacts on nutrient loading to aquatic systems and has been linked to deteriorating water quality globally. While many relationships between LULC and nutrient loading have been identified, characterization of the interaction between LULC, climate (specifically variable hydrologic forcing) and solute export across seasonal and interannual...

Do you ever wonder where your water comes from? If you live in Nassau or Suffolk County, the answer is, groundwater. Groundwater is water that started out as precipitation (rain and snow melt) and seeped into the ground. This seepage recharges the freshwater stored underground, in the spaces between the grains of sand and gravel in what are referred to as aquifers. Long Island has three...

Three wells in New Hampshire were sampled bimonthly over three years to evaluate the temporal variability of arsenic concentrations and groundwater age. All samples had measurable concentrations of arsenic throughout the entire sampling period and concentrations in individual wells varied, on average, by more than 7 µg/L. High arsenic concentrations (>10 µg/L) were measured in bedrock...

Categorical classification of groundwater age is often used for the assessment and understanding of groundwater resources. This report presents a tritium-based age classification system for the conterminous United States based on tritium (3H) thresholds that vary in space and time: modern (recharged in 1953 or later), if the measured value is larger than an upper threshold; premodern...

Daily mean discharges are needed for rivers in New Hampshire for the management of instream flows. It is impractical, however, to continuously gage all streams in New Hampshire, and at many sites where information is needed, the discharge data required do not exist. For such sites, techniques for estimating discharge are available. The U.S. Geological Survey, in cooperation with the New...

Executive Summary Background.—Pesticide results from the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) are used for water-quality assessments by many agencies and organizations. The USGS is committed to providing data of the highest possible quality to the consumers of its data. A cooperator’s inquiries about specific pesticide detections in water revealed...

Streams in the northeastern U.S. receive mercury (Hg) in varying proportions from atmospheric deposition and legacy point sources, making it difficult to attribute shifts in fish concentrations directly back to changes in Hg source management. Mercury stable isotope tracers were utilized to relate sources of Hg to co-located fish and bed sediments from 23 streams across a forested to...

As part of a long-term cooperative program to monitor water quality within the Scituate Reservoir drainage area, the U.S. Geological Survey, in cooperation with the Providence Water Supply Board, collected streamflow and water-quality data at the Scituate Reservoir and tributaries. Streamflow and concentrations of chloride and sodium estimated from records of specific conductance were...

In spring 2016, a 310-foot-deep boring (named MA–FSW 750) was drilled by the U.S. Geological Survey near Nantucket Sound in East Falmouth, Massachusetts, to investigate the hydrogeology of the southern coast of western Cape Cod. Few borings that are drilled to bedrock exist in the area, and the study area was selected to fill a gap between comprehensive geologic datasets inland to the...