Boron Levels in Drinking Water Sources from the Volcanic Area of Sicily (South Italy): Risk Evaluation of Developing Chronic Systemic Effects

Abstract

Short-and long-term oral exposures to boric acid or borax demonstrated boron toxicity in reproductive system. European Union standard of boron in drinking water has a maximum allowable concentration of 1 mg/L, but in Sicily (south Italy) there are often higher concentrations. Accordingly, the main objectives of this study, the first of its kind in the south Italy, were (1) to monitor the boron levels in drinking water sources from Mt. Etna, and (2) to estimate the daily intake (EDI) and the Target Hazard Quotient (THQ) in adult population to evaluate the risk of developing chronic systemic effects due to drinking boron intake. We divided the study area into five sectors. Mt. Etna water sources, were collected from 2000 to 2014 and were analyzed by inductively coupled plasma -optical emission spectrometry (ICP-OES). We found boron mean values ranged from 0.199 to 0.863 mg/L with minimum and maximum concentrations of 0.010 and 2.620 mg/L, respectively. Adult EDI concentration was between 0.004 and 0.020 mg/Kg day, thus below the Reference Daily Dose (RfDo) suggested by the Environmental Protection Agency (EPA). THQ always resulted below the level of risk, indicating no risk to develop chronic systemic effects due to drinking boron intake during the lifetime. primarily through oral intake of food and drinking water. Intakes of boron for humans are been expected to be 0.44 µg/day from ambient air, 0.2-0.6 mg/day from drinking water and 1.2 mg/day from the diet [9]. Previous studies performed with experimental animals indicated that over 90% of boric acid and borax administrated could be absorbed through the gastrointestinal and respiratory tracts [10-12]. In most parts of the world, the concentration range of boron in drinking water is between 0.1-0.3 mg/L [6]. The limit values suggested for boron in drinking water from WHO and UE are 0.5 and 1 mg/L respectively [6,13]. Recently, WHO has suggested to convert the current limit acknowledged by EC to 2.4 mg/L [14]. Mount Etna host a major aquifer that provides drinking water to more than 750.000 inhabitants and irrigation to large agricultural areas nearby. Water from this aquifer and the volcanic soil undergoes a magmatic-type interaction, in which excess CO 2 in volcanic gas leads to acidification of water and to leaching of chemicals from the basalt rock, especially on the lower South-South-Western and Eastern flanks of the volcano. Various elements and chemicals (HCO 3 , solphates, calcium, fluoride, chloride, magnesium, boron, manganese, iron, vanadium and their salts) are often higher in water samples from various sources of this volcanic aquifer [15]. Thus, the present study aimed to monitor the boron levels in drinking water sources of the volcanic area of eastern Sicily (south