Prevention and mitigation measures against groundwater contamination

Groundwater provides most of the drinking water in Europe and in Italy. Since groundwater systems are very prone to pollution induced by human activities (but also natural events), it is of pivotal importance to reduce the risk of contamination of this natural resource. The risk of contamination of a drinking water well can be reduced starting from the design phase by choosing its position in a low vulnerability system. After its construction, the best way to maintain high quality drinking water is to prevent contaminants from reaching drinking water sources. This can be attained by defining a wellhead protection area (WHPA) which is regulated in order to minimize hazardous operations in such areas. WHPAs can be defined according to several criteria among which the most effective is based on the time of travel. Despite the implementation of the abovementioned safety measures it's not uncommon to detect pollutants migrating towards water wells. Several actions can be undertaken in order to protect the citizens by remediating the contaminated aquifer systems, even if these operation are quite often difficult and expensive. Typical approaches to restore water quality such as pump&treat, permeable reactive barriers, air sparging, etc will be described highlighting relative merits.