Metals occur naturally in the soil, but in many places in Sweden and the rest of the world are levels of toxic metals elevated, both due to emissions from point sources in limited areas and more diffuse dispersion over large areas. One example of this is the Falu copper mine in Falun.
Particularly problematic in this context are the metals arsenic, lead and cadmium, which we also ingest via, for example, various foods and which, even at low intakes, can have certain toxic effects. Estimates of the levels of these metals that can occur in soil without posing a health risk can therefore be very low (close to natural background levels). Low levels in soil do not cause acute poisoning, but could pose a health risk to the population if many people are exposed over a long period of time. It is therefore important to reduce exposure for all, especially for sensitive groups such as pregnant women and children.