A study by UMU and UPCT links the 2021 fish death in the Mar Menor with a nitrate 'boom' | The truth

This appears in the conclusions of the work called 'Quantification of main inorganic contaminants in a Mediterranean coastal lagoon with a major dystrophic crisis', published this month in the specialized journal 'Bulletin of Environmental Contamination and Toxicology'. The main author is Carmen García Onsurbe, engineer in agri-food industries and biological systems from the UPCT. Co-authors are physicists Antonio Soto and Manuel Caravaca, from the Polytechnic and UMU, respectively, and Yésica Vicente, from the Faculty of Chemistry of the latter university.

The researchers carried out 72 chemical analyzes of samples of seven compounds – including nitrogen, phosphates and heavy metals – taken at twelve points in the lagoon, on six different dates between May 2021 and November 2022.

Descent in the Albujón

Using ion chromatography and mass spectrometry techniques, they found that even in points where the concentration of nitrates was below the detection limit, they exceeded 20 milligrams “after the appearance of numerous dead fish.” In areas where concentrations were much higher before the crisis, such as the mouth of the Albujón Rambla, levels dropped. And there were significant values ​​of lead and cadmium in two areas where mining dams flow.

On the last sampling date, decreased concentrations of all compounds were measured at each point, “coinciding with the apparent good condition of the lagoon.”