Thallium Contamination of Drinking Water: Health Implications in a Residential Cohort Study in Tuscany (Italy)

Abstract

In 2014–2015, concentrations of thallium above the recommended reference value (EPA: 2 µg/L) were measured in some parts of the drinking water distribution system in the municipality of Pietrasanta (Tuscany, Italy). An extensive campaign of water samples and human biomonitoring surveys were implemented to quantify the exposure of population. A residential cohort epidemiological study was carried out on the population of the municipality of Pietrasanta, aimed at comparing the health status of residents in the areas affected by thallium contamination with residents living in the rest of the municipality. Cohort included people residing in the municipality of Pietrasanta from 1 January 2000 to 31 December 2015. Residence addresses were georeferenced and each subject living in one of the three contaminated areas were defined as exposed. Mortality, hospital discharge data and adverse pregnancy outcomes were taken from administrative health databases. Cox proportional hazard models and logistic models were used to test the association between thallium exposure and health outcome. This study did not show any excess of risk in terms of mortality and hospitalization in the population residing in the areas served by thallium-contaminated aqueduct branches, compared to the rest of the not contaminated area. Increased risks for low birth weight (OR = 1.43 95% CI 0.91–2.25) and pre-term birth (OR = 1.40 95% CI 0.82–2.37) were observed. In view of the paucity of epidemiological studies on thallium, this study is an important contribution to the state of knowledge of the health effects of chronic exposures to low concentrations of thallium.

Removal of Thallium from Aqueous Solutions by Adsorption onto Alumina Nanoparticles

“…Examples of criteria can be found in references [6,7]. In the United States, the maximum Tl level in drinking water and wastewater discharge has been set at 2 and 140 µg/L, respectively, by the USEPA [6,[16][17][18][19]. In China, the Tl concentration limit has been lowered to 0.1 µg/L and 2 µg/L for drinking water and industrial wastewater, respectively, in some provinces [6,7].…”

“…To date, few studies have reported adsorption behavior and removal efficiency of thallium (I) at low concentration. As a matter of fact, most of the investigations were carried out at high thallium (I) concentration ranging from 1-150 mg.L −1 , whereas thallium is found to be in the range of a few µg.L −1 in real polluted water sources [11,16,28]. In this paper, the removal of Tl(I) ions at low concentration, through adsorption onto synthesized gamma-alumina nanoparticles, was investigated for the first time.…”

Geochemical Evidence of Potential Groundwater Contamination with Human Health Risks Where Hydraulic Fracturing Overlaps with Extensive Legacy Hydrocarbon Extraction

“…If the Cl contamination is accompanied by contaminants such as thallium, this could be of concern. Notably, the ingestion of thallium above the USEPA MCL in drinking water has previously been associated with increased risk of low birth weights, 64 and low birth weights have been documented in populations in SWPA exposed to a high density of UOGD. 43 These results point toward potential human exposure risk via water supplies contaminated by UOGD in limited areas.…”

Thallium distribution in an estuary affected by acid mine drainage (AMD): The Ría de Huelva estuary (SW Spain)

“…However, different studies dealing with human health effects after Tl chronic ingestion provide contradictory results. For instance, Nuvolone et al (2021) studied the effect of high Tl concentrations (above EPA recommended reference values) in the drinking water distribution of Tuscany (Italy) and they did not report any excess of risk in terms of mortality and hospitalization in the population exposed to Tl compared to those non-exposed from other not contaminated areas. On the other hand, Campanella et al (2019) reviewed the toxicity of Tl at low doses and highlight that Tl exposure, even at very low concentrations, represents a threat to human health, recommending to revise the concentration limits of Tl in the various environmental compartments.…”