The Ytterby mine is located on Resarö island in the Stockholm archipelago. Mainly feldspars but also quartz were historically quarried in the mine, which is also the place of discovery of seven rare earth elements (REE). During the cold war era, the mine shaft was used as a diesel and jet fuel deposit for the Swedish Armed Forces. Recently, a spatial coupling between multiple sclerosis (MS), a chronic neurodegenerative disease in the central nervous system, prevalence and the quarry has been suggested. Previous studies show that adverse neurological health effects are associated with oral intake of REEs and there is support for a coupling between ionizing radiation and MS. The extent and character of health effects as a result of exposure to petroleum products are still debated. However, a substantial number of scientific reports support a coupling between neurodegenerative health effects and toxic constituents of jet fuels such as benzene, toluene, and n-hexane.

My data show that a possible overrepresentation of MS patients within the Ytterby postal code area could be an indication of a spatial coupling between the mine and MS. Such a possible coupling could be associated with the REEs present in the local rocks, with the previous storage of diesel or jet fuel MC-77 in the mine and/or with zones of high natural radioactivity in the area. Water samples collected in 15 wells in the Ytterby village show traces of five REEs, i.e. scandium (Sc), yttrium (Y), lanthanum (La), neodymium (Nd) and samarium (Sm) and the majority of sample locations at low ground elevation show contamination of diesel which is the most recent fuel stored in the mine. Moreover, results from an analysis of a black substance leaking out of cracks in the mine corridors confirm that REEs are present in substantial concentrations in the local rocks and also appear to be mobile. This should be taken into account when considering a potential contamination of the local water supply. Measurements of natural radioactivity have also been made around the contours of the quarry and zones of high ionizing radiation have been identified. By using these zones of high ionizing radiation as a proxy for rare minerals containing rare earth elements, I further suggest that the REE occurrences are highly localized around the quarry and could be associated with, or remobilized by, younger faults.  My data show that a full investigation is warranted of a possible spatial coupling between neurological health issues, MS being one of them, and the mine.