Total and pentoxide vanadium in drinking water supplies from volcanic area of Mt. Etna (Sicily, Italy)

摘要

Background Vanadium exists in different oxidation states from -1 to +5. It dissolves in natural waters as V(Ⅳ) and V(Ⅴ) which have different nutritional and toxic properties. In groundwater from volcanic areas the concentrations of vanadium achieve high levels. Aims Purpose of our study is to evaluate the concentrations of total vanadium and pentoxide fraction in the drinking water supplies of 21 Etna villages, and estimate the daily intake (DI) of the V(Ⅴ) in adults and children. Methods We analyzed samples from April 2010 to December 2011, performing total V determination in ICP-MS, and speciation of V(Ⅴ) in IC-ICP-MS. Then we calculated the DI linked to consumption of water considering an ingestion rate of 2L for adults (70 Kg of body weight, 70 years old), and of 1L for children (16 Kg of bw, 6 ys). Results Among the 21 Etna countries considered, 5 exceed the limit imposed by the Italian Ministerial Decree (M.D. 22Th December 2011) of 140 μg/L, and results range from 179,8 to 187,1 μg/L, instead 10 exceed the 50 μg/L limit imposed by previous M.D. N. 31/2001, with results range from 62,5 to 87,1 μg/L. DI of the V(Ⅴ) calculated range from 0.0003 in 0.0051 mg/Kg/day in adults and from 0.0006 to 0.01112 mg/Kg/day in children. Conclusion The data in our possession show that the Etna villages with a higher concentration of vanadium (Total and V(Ⅴ)) in waters supllies located in the western part of the volcano Etna. Till date, WHO have no set a provisional tolerable intake for V(Ⅴ), the more toxic species, for the lack of consistent data on human toxicity. Only EPA have calculate the reference dose (RfDo - 0.009 mg/Kg/day), but it is referred only to decreased hair cysteine. Our DI results might be useful for future evaluations, when toxicological data on V(Ⅴ) will be improved for the assessment of risk areas.