Publications

The two-dimensional numerical model ELAmet was used to investigate the effect of adsorption kinetics on the apparent distribution coefficients of Cu, Cd, and Zn in south San Francisco Bay, California. The numerical experiments were designed to determine whether adsorption kinetics can control the basin-scale variability of the observed partitioning and to define the conditions under...

No abstract available.

It is generally recognized that the southern Arabian Peninsula has had two wet periods in the late Quaternary. To quantify ‘wet’ a 28 000 year old capillary surface associated with a paleowater-table was mapped and used as a surrogate for the water table in a ground-water model. Analysis of this model suggests 1.4 mm year−1 of recharge is necessary to support the water table at the...

The molecular sewage indicator, coprostanol, was measured in bed sediments of the Mississippi River for the purpose of determining sewage contamination. Coprostanol is a non-ionic, non-polar, organic molecule that associates with sediments in surface waters, and concentrations of coprostanol in bed sediments provide an indication of long-term sewage loads. Because coprostanol...

An air-pressurized slug test consists of applying a constant pressure to the column of air in a well, monitoring the declining water level, and then releasing the air pressure and monitoring the recovering water level. Such tests offer a means of estimating formation transmissivity and storativity without extensive downhole equipment and the associated safety risks. This paper analyzes...

Pb2+ and Zn2+ adsorption was studied in batch experiments with material collected from a shallow, unconfined aquifer of glacial outwash sand and gravel in Falmouth, Massachusetts, USA. The aquifer solids contain primarily quartz (95% w/w), with minor amounts of alkali feldspars and ferromagnetic minerals. Pb2+ and Zn2+ adsorption experiments with various grain size and mineral fractions...

The problem of the origin of the continental crust can be resolved into two fundamental questions: (1) the location and mechanisms of initial mantle extraction of the primitive crust and (2) the processes by which this primitive crust is converted into the continental crust that presently exists. We know that Archean continental crust is compositionally distinct from younger continental...

This article discusses preliminary results from analyses of USGS hydrodynamic data collected as part of the 1994 Interagency Ecological Program entrapment zone study. The USGS took part in three 30-hour cruises and deployed instruments for measuring currents and salinity from April to June. This article primarily focuses on the analysis of data from five Acoustic Doppler Current ProUers...

In order to assess the effect of filled waste disposal trenches on transport-governing soil properties, comparisons were made between profiles of undisturbed soil and disturbed soil in a simulated waste trench. The changes in soil properties induced by the construction of a simulated waste trench were measured near the Radioactive Waste Management Complex at the Idaho National...

Multiple indicators (Chl a, C : N ratios, [δ13C]POC, and two classes of lipid biomarker compounds- sterols and phospholipid ester-linked fatty acids) were used to evaluate spatial and temporal variations in the origin of particulate organic matter (POM) in the San Francisco Bay (SFB) estuary. Comparisons were made between the northern and southern subestuaries of SFB, as well as along...

No abstract available.

Upward discharge of fresh groundwater into a mid-Atlantic intertidal wetland contributed 62% of the water needed to replace evapotranspiration losses from the sediment during an 11 day period in September. Infiltration during flooding by tides provided most of the balance; thus there was a net advection of salt into the sediment. The amount of groundwater discharge was estimated from...