A helium‐enabled Niton X‐ray analyser (HHpXRF) study of 296 lava stepping stones from ancient Pompeii showed that their surfaces were contaminated with superficial deposits of Zn and Pb. Ray Laurence discusses that concentrations of these elements are highest in urban areas, where they were attributed to tyre dust and leaded petrol, respectively. Image courtesy of Ray Laurence.

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Image courtesy of interviewee. September 28, 2021