Buone pratiche per il campionamento delle acque sotterranee: proposta di un protocollo

The aim of this paper is to define, starting from a national and international literature review, a sampling procedures for monitoring groundwater quality and for the characterization of contaminated sites. The necessity to write this paper is due to the current lack of a specific national guidelines for groundwater sampling, as APAT-IRSA.CNR (2003) guidelines for the superficial water, although sometimes applicable also to groundwater, are focused on surface waters. In addition, the error linked to sampling procedures brings a far greater contribution (up to 50%) to the final error then that linked to the analytical procedures. Therefore, a proposal for GW sampling guidelines was developed; these include all aspects such as the reconstruction of conceptual model, the planning phase, the sampling phase and the quality control. The sampling phase includes: 1) selection of sampling point; 2) census and inspection of sampling point and collection of relative information; 3) piezometric level measurement in monitoring wells /piezometers or measurement of discharge in springs ; 4) purging of monitoring wells /piezometers until chemical-physical parameters stabilization; 5) measure of chemical-physical parameters through multiparameter probes with flow cell; 6) collection of GW samples in suitable containers, filtration and preservation; 7) transport of samples in refrigerate box; 8) preservation of samples in laboratory until analysis. The suggested quality control consists of field blanks, transportation blanks and rinsate blanks