LTLeco: trophic level of lakes for the Ecological State

The LTLeco index, introduced by Ministerial Decree 260/2010 (amending the technical standards of Legislative Decree 152/2006), considers the total phosphorus parameters, transparency and dissolved oxygen (as hypolymnic oxygen expressed as a percentage of saturation). The calculation procedure provides for the award of a score for each parameter according to the criteria set out in the specific tables of Ministerial Decree 260/2010; the sum of the individual scores is the score to be assigned to the LTLeco index, useful for assigning the quality class according to the class limits defined in Table 4.2.2/d of the Decree. The quality is expressed in three classes: Elevated, Good and Sufficient. The classification of lake water bodies according to the LTLeco index is based on the processing of data for the three-year period (the individual years are not evaluated) for the award of the score to each parameter, from which the LTLeco score is directly calculated. If several sites are monitored in the same body of water, the lowest status of the individual stations shall be considered. Limited to the transparency parameter, the limits laid down in the legislation may be waived if the cause is the presence of suspended mineral particulate matter depending on the natural characteristics of the lake.