A case of thallium intoxication by walking in a field

Thallium intoxications are a rare occurrence in forensic sciences. This paper reports a case of chronic thallium poisoning in a couple hospitalized in Milan, Italy, in which toxicological analyses were performed by the Institute of Legal Medicine of Milan on the request of the Judicial Authority. Preliminary analyses confirmed the presence of thallium in the blood and urine samples of the couple. After positive results were obtained from the biological samples, the Judicial Authority learned that the son of the couple used thallium powder illegally in his field and that the father helped his son in that field almost every day. Therefore, the Judicial Authority suspected that the man had accidentally contaminated the house environment, thus intoxicating his wife. Consequently, they requested the seizing of multiple items from their residency to verify this hypothesis. Each object was sampled internally (content or internal surface) and externally (surface of the container) and the concentrations of thallium were evaluated using ICP-MS analyses. Positive results of items indicate a thallium contamination caused by an external vector. Indeed, they suggest that none of the elements analyzed was the contaminant responsible for the intoxication but the examination of the soles of the man’s shoes argued in favor of an external contamination (the son’s field), suggesting that he was the accidental mean of transportation of the heavy metal into the house. This paper presents a rare case of chronic thallium intoxication in a domestic setting where contamination occurred from an illegal usage of thallium in a field.