Environmental performance, indicators and measurement uncertainty in EMS context: a case study

EMS is a tool for managing the interaction between the organization and the environment. The aim of an EMS is to improve the overall environmental performance of the organization. The performance should be monitored through measurements, and managed by indicators. Indicators are variables that summarize or otherwise simplify relevant information about the state of a complex system. A correct evaluation of environmental performance arises from the choice of adequate "raw" data and from the relationships among "raw" data. This paper, after a short excursus concerning the rule of indicators in environmental performance evaluation and the mean of uncertainty, proposes an approach to the study and the evaluation, through indicators and indices, of the environmental aspect "wastewater discharges" of a Local Authority who is involved in EMS implementation. Particularly, the critical analysis of one of the indices that has been used is reported. The role of the uncertainty of measurements has been stressed. The results showed that measurement uncertainty is essential for an efficient data comparison and for a correct evaluation of environmental performance, which, in turn, is essential to guarantee the effectiveness of the EMS application.