Vanadium in drinking water: toxic or therapeutic?! Systematic literature review and analysis of the population exposure in an Italian volcanic region

Background Vanadium (V), an element often present in the water from volcanic springs, has been investigated in several studies that focused both on possible therapeutic and toxic effects to human health. Because of this, the Italian Ministry of Health, in transposing Directive 98/83/CE , has established, for V in drinking water, a value which does not exceed 140 µg/L. The purpose of this study is to analyze the concentration of V in the drinking water of a volcanic area of Sicily Region (Italy) with the aim of assessing the existence, through the review of literature and the study of its health impact on the population, a possible correlation between high concentrations of this metal and the onset of certain diseases or, on the contrary, any health benefits. Methods The concentration of V was assessed, through atomic absorption spectrometry, in 88 sources belonging to 5 catchments located in the volcanic area of Etna. Besides, a literature review and epidemiological study on V health effects was carried out by two researchers separately. Results The average concentration measured of V was 15,5µg/L, below the limit imposed by the European and Italian law (140µg/L). The highest average concentration was measured in South Eastern catchment (30.9±4.2 µg/L). The spring that reported the highest concentration of V was the source of water called Ciapparazzo (188±7.7 µg/L). The systematic review of literature has yielded conflicting results, sometimes not clear and not definitive. In some studies, the V is considered to be toxic, while most of the studies do not define it as well or only at doses much higher than those found in Sicily drinking water. In addition, preliminary results of cohort study, still in progress, have not to date demonstrate any toxic effect due to V. Conclusions Our results show that concentration of V can generally be, even in a volcanic region, in the average of allowable values, although sometimes some sources exceed the limit. To date, it is not possible to state with certainty whether the resulting exposure of the population to high levels of vanadium is responsible of the onset of diseases. A large cohort study to assess the effects of exposure to V is needed to establish its therapeutic or toxic effects. Main Message It isn’t decided yet if the V in drinking water of an Italian volcanic region is toxic, inert or even therapeutic, although it is possible to state that the V doesn’t act as an endocrine disruptor.