Groundwater-Related Risk Assessment

Abstract

Groundwater includes the pore water in the water-unsaturated upper soil layer as well as water usually referred to as groundwater, that is, the water in the water-saturated zone. Groundwater contains contaminants of natural and anthropogenic origin. It is generally recognised by all segments of society that fresh water is an immensely important resource. From a Risk Assessment point of view, groundwater needs to be approached from two different perspectives, namely, as an important protection target and as a means of transport (a pathway) for contaminants. For human beings the primary use for groundwater is as a source of drinking water. Although often underestimated, the water-saturated deeper soil layer is also a habitat for many organisms. For decades, there has been an on-going and interesting discussion concerning the intrinsic value of groundwater, sometimes including spiritual and even supernatural or religious arguments. Generally speaking, the transport of water and contaminants is much faster in the groundwater zone than in the water-unsaturated upper soil layer. Specific attention will be given in this chapter to the impact that a revised quantitative groundwater regime, the presence of heterogeneous soils or aquifers, surface water bodies, anthropogenic subsurface processes and structures, and heterogeneous soils and aquifers all have on groundwater quality. Additional attention will be paid to sustainable protection of groundwater resources, Conceptual Models, mathematical (numerical) models, Risk Management (including Natural Attenuation and regional approaches), sampling and monitoring, lysimeters and column experiments, the impact of climate change, mingling groundwater plumes, risk perception and communication, and the European Water Framework Directive.