Identifying sources of chlorinated aliphatic hydrocarbons in a residential area in Italy using the integral pumping test method Luca Alberti & Silvia Lombi & Andrea Zanini Abstract The results of integral pumping tests (IPTs) performed in the city of Fabriano, Italy, are presented. The IPT methodology was developed by the European Union project INCORE, as a tool for groundwater investigation and source localization in contaminated areas. This methodology consists of a multiple-well pumping test in which the wells are positioned along a control plane downstream of suspected contaminant source zones and perpendicular to the mean groundwater flow direction. During the pumping, concentration time series of target contaminants are measured. In Fabriano, two control planes were realized to identify a chlorinated aliphatic hydrocarbon plume, to estimate the mass fluxes and draw up a ranked list of the main contamination sources. A numerical flow model was implemented to support the IPT design and to interpret the results. This study revealed low-level trichloroethylene contamination (concentration below 8μg/l), tetrachloroethy- lene contamination (mean concentration up to 500μg/l) and a mass flow rate of about 300g/day. Through the application of the IPT method, the mean contaminant concentrations, the spatial distribution of concentration values along the control planes, and the total contaminant mass flow rates were evaluated, and the investigation area was reduced for further and deeper investigation activities. Keywords Groundwater monitoring . Contamination . IPT . Source localization . Italy Introduction The city of Fabriano is located in the centre of Italy (Fig. 1) and is famous for high-quality paper production, which started in the thirteenth century. Local industry has experienced a new development surge since the 1950s thanks to ongoing paper production and newer domestic appliance factories. In recent years, in the Fabriano alluvial aquifer, chlorinated aliphatic hydrocarbon (CAH) contamination has been identified (Fig. 2; Table 1). In particular high concentrations values of tetrachloroethy- lene (PCE) and trichloroethylene (TCE) were detected. The presence of several industrial businesses and changes in land use and ownership make the pollutant sources difficult to identify using only a monitoring wells network. In agreement with the Municipality of Fabriano, the integral pumping test (IPT) method was applied, to: 1. Identify the path of the plume 2. Draw up a ranked list of the probable source areas 3. Plan the next investigation steps on the ranked list areas IPT methodology was developed and applied during the INCORE project (Integrated Concept for Groundwater Remediation 1999), funded by European Union in the fifth Framework (EVK1-CT-1999-00017). IPT enables the esti- mation of mass flow rates, mean contaminant concentrations and the spatial distribution of concentration values at control cross sections. The study area considered in this report is a residential/industrial area and for this reason the application of IPT resulted in logistical challenges including: the water discharge, the installation of water-treatment systems and the interruption of private and industrial well withdrawals. Integral pumping test (IPT) IPTs are pumping tests performed at one or more pumping wells with variable capture zone widths and located along cross-sectional control planes (CPs) perpendicular to the mean-groundwater-flow direction, downstream from sus- Received: 16 March 2010 /Accepted: 26 April 2011 Published online: 19 May 2011 * Springer-Verlag 2011 L. Alberti ()) : S. Lombi DIIAR, Politecnico di Milano, Piazza L. Da Vinci 32, 20133 Milano, Italy e-mail: luca.alberti@polimi.it Tel.: +390223996663 S. Lombi e-mail: silvia.lombi@polimi.it A. Zanini DICATeA, Università degli Studi di Parma, Viale G. P. Usberti 181/A, 43100 Parma, Italy A. Zanini e-mail: andrea.zanini@unipr.it Hydrogeology Journal (2011) 19: 1253–1267 DOI 10.1007/s10040-011-0742-1