A new, accurate, and experimentally simple method has been developed to determine dimensionless Henry's law constants using the static headspace method. The method appears applicable to a wide range of volatile and semivolatile organic compounds. Themethod worked well even for methyl tert-butyl ether (MTBE), despite its very high water solubility and hence, low Henry's law constant. The approach developed extends the usefulness of the static headspace method in obtaining real-time, accurate information for assessing environmental problems.

This paper develops an analytical expression for contaminant transport from a finite source in a continuous flow regime. The model requires some numerical integration and its degree of accuracy for near‐field problems depends on discretization procedures applied to the source boundary. A second model for a continuous source is developed by extending a well‐known pulse model. This second model is particularly useful in that it permits the determination of several potential unknowns directly from a concentration distribution. These include the source concentration, source dimensions, the position of the center of mass which is the product of the seepage velocity and the time since the contaminant first entered the ground water, and up to three dispersivities for a three‐dimensional problem. As a demonstration of its utility, this second model is applied with reasonable success to a well‐defined field condition. A comparison of the two models indicates that, except for minor differences in the very near field, the results from each are virtually identical.

Continuous point source and instantaneous finite source methods are presented for determining the transverse dispersion coefficient of saturated porous media in laboratory column experiments. The methods entail injecting a conservative tracer from an injector embedded in a porous medium, monitoring concentration variations with time within the column upgradient from where the tracer impinges on the column wall, and extracting longitudinal and transverse dispersion coefficient values from relative concentration‐time data using three‐dimensional advection‐dispersion formulations. The methods were tested in a column packed with glass beads for comparison with reported flow tank tests. The transverse dispersion coefficient values calculated using column test data agree closely with flow tank results. The methods presented offer new approaches for investigating dispersion phenomena in porous media and especially offer the potential for determining the transverse as well as the longitudinal dispersion coefficient of undisturbed core samples.

This study examined the extent to which development and road salting has affected Connecticut's groundwater. We gathered water quality data from different time periods between 1894 and the present and analyzed the data using maps generated with ESRI ArcGIS. Historical reports illustrate a statewide baseline trend of decreasing chloride concentration northward across the State (average, 2 ppm). Since then, statewide chloride concentrations in ground water have increased by more than an order of magnitude on average. Analysis indicates spatial correlation between chloride impacts and major roadways. Furthermore, increases in statewide chloride concentration parallel increases in road salt application. Projected trends suggest that statewide baseline concentrations will increase by an amount equal to five times background levels between the present and the year 2030. The analytical process outlined herein can be readily applied to any region to investigate salt impacts on large spatial and temporal scales.

The vertical distribution and partitioning (between the solid and aqueous phase) of chromium in a glaciofluvial aquifer in northeastern Connecticut were assessed. Most of the chromium (99 percent of its mass) is bound to the soil. Retardation is primarily the result of binding to organic matter and adsorption to iron oxide coatings. However, other attenuation mechanisms also appear to be significant. If the degree of chromium binding observed here is representative of other chromium contaminated sites, pump‐and‐treat remediation will not remove the vast amount of chromium from the subsurface. However, most of the chromium may be immobile, and removal may not be required following the initial pumping to remove the mobile fraction. Further knowledge of the mechanisms that bind chromium to the soil, their reversibility, and their kinetics is essential to developing effective remediation strategies.