Karst aquifers are a particular type of groundwater system that supplies drinking water in Puerto Rico, as well as in several U.S. regions and around the world. The karst aquifers contain cave systems that are vulnerable to contamination from toxic chemicals, such as TCE. This is because these contaminants tend to be trapped in the rock formations as nonaqueous phase liquids (known as NAPLs) an...

Many communities obtain their drinking water from underground sources called aquifers. Official water suppliers or public incorporations drill wells into soil and rock aquifers look‐ ing for groundwater contained there in order to supply the population with drinking water. An aquifer can be defined as a geologic formation that will supply water to a well in enough quantities to make possible th...

Sequestration of carbon dioxide (CO2) in deep saline aquifers has emerged as an option for reducing greenhouse gas emissions to the atmosphere. The large amounts of supercritical CO2 that need to be injected into deep saline aquifers may cause large fluid pressure increases. The resulting overpressure may promote reactivation of sealed fractures or the creation of new ones in the caprock seal. ...

Introduction Dense non-aqueous phase liquids (or DNAPLs) are liquids that are water immiscible and at the same time are heavier than water. When a spill occurs, these liquids can migrate into aquifers and become trapped in the pores. Some techniques proved to be efficient for the recovery of DNAPLs from the aquifers. One method is the injection of fluids through injection wells, for example, co...

Geologically and chemically distinct aquifers were screened for the presence of two genes coding for key enzymes of the reverse tricarboxylic acid (rTCA) cycle in autotrophic bacteria, 2-oxoglutarate : ferredoxin oxidoreductase (oorA) and the beta subunit of ATP citrate lyase enzymes (aclB). From 42 samples investigated, aclB genes were detected in two and oorA genes in six samples retrieved fr...

Much of the existing conceptualization of fluid flow in karst aquifers is based on work in extensively cemented and recrystallized Paleozoic and Mesozoic carbonates. Within these aquifers, flow is often primarily through conduits (White 1969, 1977; Smart and Hobbs 1986; Ford and Williams 1989), although diffuse flow may occur through secondary porosity, such as fractures and joints (Shuster and...

The technology presents a number of environmental challenges as the wells are drilled vertically through aquifers on their way to the deep shale deposits thousands of feet under the surface, and then turned horizontally and drilled another several thousand feet through the shale deposit. Herein lies the challenge: in the process of drilling the wells and preparing them for production (including...

[1] Young flood channels emanate from Cerberus Fossae, Mars. In order to determine whether subsurface aquifers can discharge water sufficiently fast to explain these flood features, I develop a model that couples groundwater flow in a sub-cryosphere aquifer with flow through a fissure that penetrates from the surface to the aquifer. The model is constrained by estimates of peak discharge, and t...

The health of tens of millions of people world-wide is at risk from drinking arsenic-contaminated well water. In most cases this arsenic occurs naturally within the sub-surface aquifers, rather than being derived from identifiable point sources of pollution. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Incr...