Mr Loxham adds: "Underground rail travel is used by great numbers of people in large cities all over the world, for example, almost 1.2 billion journeys are made per year on the London Underground. The high level of mechanical activity in underground railways, along with very high temperatures is key in the generation of this metal-rich dust, and the number of people likely to be exposed means that more studies into the effects of particulate matter in the underground railway environment are needed, as well as examining how the levels of dust and duration of exposure might translate to effects on health."
The Southampton team, which included the Geochemistry Group at the National Oceanography Centre, Southampton and the Inhalation Toxicology Group at the National Institute for Public Health and the Environment (RIVM) in Bilthoven, initially collected airborne dust from a mainline underground station underneath an airport in Europe. The metal content of the dust was analysed and a detailed elemental profile was established for each dust sample. These profiles were then compared to profiles from other dusts analysed at the same time, for example dust from wood-burning stoves and a heavily-trafficked road tunnel, showing that underground particles were very rich in metals, especially iron and copper. The shapes of individual particles were examined and gave clues as to how the particles were generated. The team then showed that the dust was capable of generating reactive molecules which are fundamental to their toxic effects, and that this was dependent on the metal content of the particles and, importantly, occurred to a greater extent
|Contact: Becky Attwood|
University of Southampton