A mini review of the toxicity of Thallium (Tl) at low doses is herein presented. Thallium has severe toxicity. Although its acute biological effects have been widely investigated and are well known, its biological effects on human health and in cell cultures at low doses (<100 μg/L) due, for example, to Tl chronic exposure via consumption of contaminated water or foods, have often been overlooked or underestimated. Relatively few papers have been published on this topic and are herein reviewed to provide a focused scientific opinion in the light of current worldwide regulatory issues.

This study deals with arsenic distribution in groundwater, soil and edible vegetables in the densely populated area of the Versilia Plain (Tuscany region, Italy), addressing potential impacts on people’s health. The data revealed high As concentrations in some domestic irrigation wells, exceeding 1200 µg/L. The average As concentration in topsoil and subsoil was 39 and 46 mg/kg, respectively, with the highest concentration reaching about 200 mg/kg. Arsenic concentrates in plant roots compared with the edible parts; in tomato fruits, black cabbage leaves and edible leek parts As reached about 0.2 mg/kg, 0.4 mg/kg and 3 mg/kg, respectively. Geochemical and hydrostratigraphic data suggest that As in soils and alluvial sediments originated from mineralized and historical upstream mining areas. The exposure routes for both non-carcinogenic and carcinogenic risk assessment here considered include soil ingestion, dermal absorption, soil dust inhalation and vegetable consumption. For non-carcinogenic and carcinogenic effects, the hazard was higher than the acceptance threshold. The calculated soil screening levels resulted even lower than the guideline soil-concentration imposed by Italian regulations, and this poses an issue on the actual meaning of arsenic regulatory thresholds.