Guidelines for the identification of any significant and sustained upward trends in pollutant concentrations and for the definition of the starting point for trend reversal in groundwater
The Decree of the Italian Ministry of the Environment of 6th July 2016 modifies the Annex 1 of the Legislative Decree no. 152/2006. In particular, in order to provide useful elements for the assessment of the chemical status of groundwater bodies, a guidance is required for assessing upward trends and their reversal in groundwater pollutants. For the groundwater bodies considered "at risk", the non-parametric test of Mann-Kendall is proposed to study the ascending trend of a temporal series; the value of the trend (angular coefficient) is estimated by Sen's method. To test the existence of a reversal point within the time series, Pettitt's test is proposed. Once this procedure has been adopted at the individual sampling stations, criteria are given to attribute the proper “status” to the entire body of water. Finally, it is proposed a simplified procedure to adopt for the “not at risk” groundwater bodies.
Publication available only on-line
Download the publication (pdf - 1.3 mb)