Elements of emerging concern: The “old” new contaminants in water and sediments of a Mediterranean wetland (the Albufera Natural Park, Valencia, Spain).

In recent years increasing attention has been paid to a to a group of inorganic elements widely used but not well known, mainly in their toxicological aspects. Because of this lack of knowledge their possible toxic levels have not been regulated for many of them in the different environmental compartments. It is for these reasons that they have been included in the group of “emerging contaminants” or “contaminants of emerging concern”.

In this work, the presence and spatial distribution of 15 elements (Al, As, B, Be, Bi, La, Li, Mo, Rb, Se, Sr, Ti, Tl and V), considered as emerging contaminants and most of them scarcely studied, in waters and sediments of the Natural Park of L’Albufera of Valencia (Spain) have been studied, together with the influence of the environment (land uses, water sources, etc.). The Natural Park of La Albufera (Valencia, Spain), is one of the most important marshland of Europe, included in the RAMSAR agreement, but it suffers impacts derived from the high human and industrial occupation, and of the hydrological contributions from the connected irrigation systems. It includes a coastal lagoon, marshlands, dunes and pinewoods, surrounded by rice fields, orchard and citrus crops in its not urbanized part.

In this study area, 57 sampling zones were selected covering the different water sources and agricultural types. Total concentrations of the selected 15 elements were evaluated. Standard analytical methods were used to measure water physical and chemical properties. Total content of the elements in water and sediment samples were extracted by microwave acid digestion and determined by ICP-OES-MS.

Taking in to account that for many of these elements there are not regulations or even benchmarks, Al, Li, Sr and Tl showed levels above the stablished legislation for waters with maximum values of 5182.14, 77.83, 4310.03 and 11.37 µg/L, respectively. For sediments values above the existent legislation or benchmarks were observed for As, Sb and Se with maximums of 40040.25, 17.03 and 22.17 mg/kg. Water channels that irrigates rice crops at the south of the target area, and surrounding the lake showed the highest levels in almost all metals.

This study can be a solid base to assess the state of water quality of this wetland area, extrapolable to others in the Mediterranean, and to help in the knowledge of the dynamics of metals scarcely known such as Be, Mo, Se, Sr, Ti or Tl.

Acknowledgements

This work has been supported by the Generalitat Valenciana (Spain) through the project with reference CIPROM/2021/032.