CNR researchers study the acid drainages in Baccatoio creek
Thallium is a shining, soft and malleable metal, similar to tin that, if exposed to air, oxidized and becomes gray-blue, similar to lead, until it develops, in the case of long exposure, a layer of oxide on the surface. In the presence of water, a layer of thallium hydroxide is formed.
Its name comes from the Greek thallos, i.e. “green sprout” due to its green emission lines in the spectrum, and it was identified by Claude Auguste Lamy and William Crookes using flame spectroscopy, a method developed by Robert Bunsen and Gustav Kirchhoff in the years 1859-1860.
Thallium and its compounds are very toxic and can be present in the water as both +1 ion, forming the most common thallous compounds, and +3 ion forming the thallic compounds, two species of thallium with different water solubility, different behaviors in the environment and different toxicity, resulting from the ability of the metal to replace alkali metal cations in the body, mainly sodium and potassium, disrupting many of the normal cellular processes.
The effects of poisoning due to thallium include hair loss, peripheral nervous damage, as well as suspected carcinogenicity, which is why the use of thallium for rat-poisoning has been banned in many countries. The thallium +3 species are thousands of times more toxic than thallium +1 based on the results from tests conducted on Daphna magna, a small crustacean often used for ecotoxicology tests, and other algae.
A team of researchers of the Institute of Chemistry of Organometallic Compounds of CNR in Pisa, the HydroScience research labs of CNRS-University of Montpellier (France) and the Department of Earth Sciences of the University of Pisa have developed an innovative method to measure thallium in the water of Baccatoio creek and in tap water from of Valdicastello Carducci (Lucca) with regard to water contamination due to thallium.
Even if specific studies in men are lacking, this study, published in the international journal ‘Talanta’, shows that both thalium +1 and +3 are present in the water of Baccatoio creek, and also, in variable amounts, in some samples of tap water. Thallium +3 probably comes from piping encrustations and is associated with nanoparticles that do not generate apparent turbidity.
The study used the data of Thallium +1 detected in 150 urine samples and 318 hair samples from the Valdicastello-Pietrasanta population that showed significant contamination with Thallium +1, with values higher than the population reference values.
The study results pave the way to new scenarios in the processes of thallium distribution both in surface ecosystem and in water mains system, and provide the basis to mitigate dispersion of this contaminant with strongly targeted and effective measures.
Baccatoio is a medium-sized creek that crosses Valdicastello Carducci valley that has had an important role in the development and local economy since the Middle-Ages; along the coasts of this creek, there have always been a number of mills and alive-oil mills.