Groundwater is a vital resource in steadily increasing demand by man, but man threatens its quality and mishandles the available quantity. In order to properly manage the resource, we have to study it in detail, recognize its properties, and understand its dynamics—in large-scale regions as well as in every locally studied system.
Chemical and isotopic hydrology are tailored to these challenges, and the hydrochemist has a key role as a consultant to the groundwater developers and managers, decision-makers, and environmental quality authorities

The aim of this introductory paper is to highlight those underlying chemical principles that are common to all forms of waste management by geological means, and that rely to some extent upon chemical containment. Until recently, chemical processes were usually considered mainly because they can affect the physical performance of engineered containment systems. However, in recent years, many researchers have recognized that chemical processes themselves can offer containment to wastes. Thus, it is no longer possible to view physical and chemical containment processes separately. The containment system can be optimized only if both the engineered and natural barriers are considered together, and if the engineered barrier system is designed taking the features of the geosphere into account. However, there has been relatively little reliance upon the geosphere itself as a chemical barrier. It is concluded that the potential for chemical containment should be considered in all forms of geological waste management. Even if the chemical barrier function of the geosphere is not relied upon to meet safety targets, the confidence of regulators and public alike will be enhanced if it can be demonstrated that the geosphere at the site functions as a chemical barrier. <...>

Chemical weathering of silicate minerals results from the differences in the thermodynamic conditions that existed at the time of mineral formation and that of ambient conditions at the earth's surface. The solid state characteristics of silicate minerals, generally established at high temperature and/or pressures, continue to be reflected during weathering through mineral compositions, crystallographic structures and the petrographic fabric and textures of rocks. The ambient processes which most influence silicate weathering are associated with the flow and chemistry of water at the earth's surface. The term "weathering" implies strong dependency on processes associated with the hydrosphere, atmosphere, and biosphere. <...>

Die cyansauren Salze pflegt man bekanntlich von der Isocyansäure, d. i. dem Carbimid: =C=NH^ abzuleiten, während für die den rhodanwasserstoffsauren Salzen zugrunde liegende Säure die Constitution: N^C—SH angenommen wird, analog der normalen Cyansäure N^C— OH und der unterchlorigen Säure Cl— OH, von welcher bisher kein Salz in bestimmbaren Krystallen erhalten worden ist.