Historical mining towns: The establishment of ‘Soil Planning Areas’ for the risk management of contaminated soil

Historical mining towns face financial challenges with the proposed Soil Monitoring Law of the European Union, which will require the management of soil contamination, since remediating soil in densely populated towns and cities is challenging. We compared the environmental impact of sulfide ore mining in the urban area of Outokumpu in Finland with that of other European sites, focusing on soil contamination. Soil sampling revealed that mine tailings were historically used in road construction. The threshold values of Cu, Ni, and Zn were exceeded at several points, with the highest Cu content reaching 2733 mg/kg. Groundwater and surface water contamination was also evident, mainly due to the lack of a proper protective structure in tailings to prevent acid mine drainage. A preliminary risk assessment suggests health risks from unintentional soil ingestion and dust inhalation. However, the issues in many historical mining towns are more severe if they contain high levels of As or Pb which are more toxic than those of concern in Outokumpu. The historical mining town of Freiberg in Saxony, Germany, has been regulated as a 'Soil Planning Area', where limit values have been provided based on land use scenarios. The regional handling and re-use of excavated soil is based on contamination categories, with the tightest restrictions for the areas where the As content exceeds 340 mg/kg. We suggest 'Soil Planning Areas' to be established in historical mining towns facing similar challenges as a first step to mitigate environmental and health risks with reasonable economic resources.