BRIDGE - Guidance and Recommendations on Sampling, Measuring and Quality Assurance of Groundwater parameters

The strategy for assessment of chemical status of the Ground Water Basin (GWB) being developed in the framework of the BRIDGE project consisted of several steps.The first steps consisted of the determination of natural background levels (NBLs) for suite of chemical constituents of GWB and assigning adequate threshold values (TVs) for the given system. The decision whether the given GWB is in good or poor chemical status is taken in the process of comparing TV values with the results originating from representative monitoring points. The monitoring results are the end-product of the entire analytical process and as such are unavoidably subject to uncertainty. This document reviews the current approaches towards assessing uncertainties associated with sampling, transport and storage of samples in determination of the chemical quality of groundwater. Several examples are presented which illustrate the use of these approaches in quantifying uncertainties for monitor ing networks of various sizes.