Uncertainties in monitoring data

Monitoring activities should be such as to provide the necessary data for the analysis and evaluation of environmental contamination. Monitoring, especially in emergencies, is an important information source for decision making and for the justification of countermeasures. However, as with any measurements, monitoring data have associated uncertainties that arise from technical uncertainties, the non-representativeness of samples and/or measurements, and human errors. 

The technical uncertainties in the monitoring data arise mainly from  

These uncertainties cannot be eliminated but they should be reduced as far as possible by means of quality assurance procedures. Whereas incorrect calibration may be detected and corrected at a later stage, errors in the treatment of the samples cannot readily be detected and corrected. Furthermore, the storage of samples allows the repetition of measurements for the samples that are obviously not correct. Regular training and exercises should be conducted for the staff to maintain the experience of personnel as an important precondition for high quality work, especially under stress in emergencies. 

Representativeness in sampling and/or in field measurements can be optimized by means of an appropriate sampling and measurement scheme as described above and by intensifying the monitoring activities. 

Human errors are difficult to quantify. Stress and a heavy workload, especially in emergencies, may give rise to human errors leading to, for example, improper recording, loss of samples, incorrect labelling, crosscontamination during sample preparation and contamination of measurement devices. Since many human errors can be foreseen and simulated, adequate 

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