Sampling strategies for water analysis

In Europe, since the implementation of the Water Framework Directive (WFD, Directive 2000/60/EC), water monitoring has been focused on the requirements of current legislation, the aim of which is to protect all waters (river, lake, coastal and groundwater). This directive aims to ensure that all European waters achieve "good status" by 2015, which has obvious implications for the way in which water monitoring programs will be set up and implemented from the end of 2006. In particular, to obtain quality data, we need to consider the need for quality analyses, and therefore the need for validation of techniques, including sampling.

Although analytical quality assurance and quality control procedures are now considered "standard" by most laboratories responsible for monitoring analyses (for more details, see [9]), steps such as sampling, pre-treatment, transport and sample preservation are not always considered an integral part of the analysis. In other words, sample handling procedures have not always received sufficient attention in terms of quality assurance. As such, however, they should be taken into account in the development of any sampling strategy (including site selection, sampling frequency, integrated sampling, on-line measurements). New approaches to monitoring, including "integrated" sampling, have recently been developed, offering new alternatives in terms of sampling strategy.

Various aspects of sample handling methods (equipment, sampling, filtration, preservation) are discussed in this dossier, with a view to including quality assurance and quality control procedures as an integral part of the analytical steps involved in handling samples before they are released to laboratories.