In historic mining towns, where mining activities were abandoned many decades or even centuries ago, legacy contaminations can be remobilized and redispersed, representing a threat for the environment and human health. This study focuses on urban soils (n = 19) in the town of Jihlava, the Czech Republic, one of the medieval centers of silver mining in central Europe. The basic geochemical characterization of the soils was combined with mineralogical investigations to understand the solid speciation of the metal(loid) contaminants, oral bioaccessibility tests, and exposure assessment. The total concentrations of the metal(loid)s in the original soils were not excessively high (up to 45.8 mg As/kg, 19.2 mg Cd/kg; 205 mg Cr/kg; 91.8 mg Cu/kg, 163 mg Pb/kg, 253 mg V/kg, 262 mg Zn/kg), although, in some cases, they exceeded the regulatory guidelines for agricultural and/or residential soils. A substantial increase in the metal(loid)s contents was confirmed for the < 48-µm soil fraction that was later used for the bioaccessibility tests. Scanning electron microscopy and the electron microprobe showed that ore-derived primary sulfides were rare in the studied soils. Still, hydrous ferric oxides rich in Cu, Pb and Zn and fragments of metallurgical slags composed of metal-containing glass and silicates (olivine) were prone to dissolution during extraction in a simulated gastric fluid (SGF, glycine solution acidified to pH 1.5 by HCl). The maximum bioaccessible concentrations corresponded to 4.69 mg As/kg, 1.75 mg Cd/kg, 2.02 mg Cr/kg, 20.3 mg Cu/kg, 81.6 mg Pb/kg, 16.2 mg V/kg, and 233 mg Zn/kg. Exposure estimates were carried out for children (10 kg) as a target group and a conservative soil ingestion rate (100 mg/d). However, the daily intake of all the studied contaminants was far below the tolerable limits. Our results show that the human health risk based on incidental soil ingestion in the studied area seems limited.

• Keywords
• Human health, Oral ingestion, Contamination, Exposure,
• MeSH
• Biological Availability MeSH
• History, Medieval MeSH
• Mining * MeSH
• Soil Pollutants * analysis   MeSH
• Humans MeSH
• Environmental Monitoring MeSH
• Soil chemistry   MeSH
• Metals, Heavy * analysis   MeSH
• Cities MeSH
• Check Tag
• History, Medieval MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic MeSH
• Cities MeSH
• Names of Substances
• Soil Pollutants * MeSH
• Soil MeSH
• Metals, Heavy * MeSH

We studied the dust fractions of the smelting slag, mine tailings, and soil from the former Ni-Cu mining and processing district in Selebi-Phikwe (eastern Botswana). Multi-method chemical and mineralogical investigations were combined with oral bioaccessibility testing of the fine dust fractions (<48 and <10 μm) in a simulated gastric fluid to assess the potential risk of the intake of metal(loid)s contaminants. The total concentrations of the major contaminants varied significantly (Cu: 301-9,600 mg/kg, Ni: 850-7,000 mg/kg, Co: 48-791 mg/kg) but were generally higher in the finer dust fractions. The highest bioaccessible concentrations of Co, Cu, and Ni were found in the slag and mine tailing dusts, where these metals were mostly bound in sulfides (pentlandite, pyrrhotite, chalcopyrite). On the contrary, the soil dusts exhibited substantially lower bioaccessible fractions of these metals due to their binding in less soluble spinel-group oxides. The results indicate that slag dusts are assumed to be risk materials, especially when children are considered as a target group. Still, this exposure scenario seems unrealistic due to (a) the fencing of the former mine area and its inaccessibility to the local community and (b) the low proportion of the fine particles in the granulated slag dump and improbability of their transport by wind. The human health risk related to the incidental ingestion of the soil dust, the most accessible to the local population, seems to be quite limited in the Selebi-Phikwe area, even when a higher dust ingestion rate (280 mg/d) is considered.

• Keywords
• Botswana, Ni‐Cu mining and smelting, Selebi‐Phikwe, dust, metal(loid)s, oral bioaccessibility,
• Publication type
• Journal Article MeSH