The classification of the ecological state of transition waters is based on the use of biological indicators and supporting physicochemical elements. The biological indicators most representative of the pressures typical of transition environments (nutrient enrichment, organic load, pollutants and substrate instability) are: macrophytes, benthic macroinvertebrates and phytoplankton. The chemical-physical elements supporting the biological ones are: dissolved inorganic nitrogen (DIN) and reactive phosphorus (P-PO4) expressed as an average annual value and dissolved oxygen. For these parameters, two quality classes are identified: "Good" and "Sufficient". The ecological status of the water body is classified based on the lowest class of the aforementioned indicators according to the schemes provided for by Ministerial Decree 260/2010; there are five quality classes into which it can fall: "High", "Good", "Sufficient", "Poor" and "Bad".
