The Impact of Human Errors on the Estimation of Uncertainty of Measurements in Water Monitoring

The main purpose of a physical act of measurement is to enable decisions to be made. In case of an assessment of the chemical status of groundwater body, or assessment of suitability of water for drinking purposes, or possibility of discharges sewage into surface waters, the measurements of physicochemical parameters of water are an indispensable first step. The reliability of the mentioned above decisions heavily depends on knowing the uncertainty of the measurement results. If the uncertainty of measurements is underestimated, for example because the human errors are not taken into account, then erroneous decisions can be made that can have in some cases substantial financial consequences. In this work there are presented examples of human error identification and estimation in measurements made during water monitoring on the base of duplicate control samples (empirical approach) with the use of control charts method.