The laterite Ni ore smelting operations in Niquelândia and Barro Alto (Goiás State, Brazil) have produced large amounts of fine-grained smelting wastes, which have been stockpiled on dumps and in settling ponds. We investigated granulated slag dusts (n = 5) and fly ash samples (n = 4) with a special focus on their leaching behaviour in deionised water and on the in vitro bioaccessibility in a simulated gastric fluid, to assess the potential exposure risk for humans. Bulk chemical analyses indicated that both wastes contained significant amounts of contaminants: up to 2.6 wt% Ni, 7580 mg/kg Cr, and 508 mg/kg Co. In only one fly ash sample, after 24 h of leaching in deionised water, the concentrations of leached Ni exceeded the limit for hazardous waste according to EU legislation, whereas the other dusts were classified as inert wastes. Bioaccessible fractions (BAF) of the major contaminants (Ni, Co, and Cr) were quite low for the slag dusts and accounted for less than 2 % of total concentrations. In contrast, BAF values were significantly higher for fly ash materials, which reached 13 % for Ni and 19 % for Co. Daily intakes via oral exposure, calculated for an adult (70 kg, dust ingestion rate of 50 mg/day), exceeded neither the tolerable daily intake (TDI) nor the background exposure limits for all of the studied contaminants. Only if a higher ingestion rate is assumed (e.g. 100 mg dust per day for workers in the smelter), the TDI limit for Ni recently defined by European Food Safety Authority (196 µg/day) was exceeded (324 µg/day) for one fly ash sample. Our data indicate that there is only a limited risk to human health related to the ingestion of dust materials generated by laterite Ni ore smelting operations if appropriate safety measures are adopted at the waste disposal sites and within the smelter facility.

• Klíčová slova
• Bioaccessibility, Dust, Fly ash, Laterite, Ni smelting, Slag,
• MeSH
• anorganické látky aplikace a dávkování   MeSH
• aplikace orální MeSH
• biologické modely MeSH
• chrom analýza   MeSH
• hutnictví * MeSH
• kobalt analýza   MeSH
• lidé MeSH
• nebezpečný odpad analýza   MeSH
• nikl analýza   MeSH
• odpadky - odstraňování metody   MeSH
• popel uhelný analýza   MeSH
• prach analýza   MeSH
• průmyslový odpad MeSH
• vystavení vlivu životního prostředí * MeSH
• žaludeční šťáva MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Brazílie MeSH
• Názvy látek
• anorganické látky MeSH
• chrom MeSH
• kobalt MeSH
• nebezpečný odpad MeSH
• nikl MeSH
• popel uhelný MeSH
• prach MeSH
• průmyslový odpad MeSH

Metal smelting is often responsible for local contamination of environmental compartments. Dust materials escaping from the smelting facilities not only settle in the soil, but can also have direct effects on populations living close to these operations (by ingestion or inhalation). In this particular study, we investigate dusts from Cu-Co metal smelters in the Zambian Copperbelt, using a combination of mineralogical techniques (XRD, SEM/EDS, and TEM/EDS), in order to understand the solid speciation of the contaminants, as well as their bioaccessibility using in vitro tests in simulated gastric and lung fluids to assess the exposure risk for humans. The leaching of metals was mainly dependent on the contaminant mineralogy. Based on our results, a potential risk can be recognized, particularly from ingestion of the dust, with bioaccessible fractions ranging from 21 to 89% of the total contaminant concentrations. In contrast, relatively low bioaccessible fractions were observed for simulated lung fluid extracts, with values ranging from 0.01% (Pb) up to 16.5% (Co) of total contaminant concentrations. Daily intakes via oral exposure, calculated for an adult (70 kg, ingestion rate 50 mg dust per day), slightly exceeded the tolerable daily intake limits for Co (1.66× for fly ash and 1.19× for slag dust) and occasionally also for Pb (1.49×, fly ash) and As (1.64×, electrostatic precipitator dust). Cobalt has been suggested as the most important pollutant, and the direct pathways of the population's exposures to dust particles in the industrial parts of the Zambian Copperbelt should be further studied in interdisciplinary investigations.

• MeSH
• arsen analýza   MeSH
• biologické modely MeSH
• dospělí MeSH
• hodnocení rizik MeSH
• hutnictví * MeSH
• látky znečišťující vzduch analýza   MeSH
• lidé MeSH
• monitorování životního prostředí * MeSH
• prach analýza   MeSH
• průmysl MeSH
• techniky in vitro MeSH
• těžké kovy analýza   MeSH
• velikost částic MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Zambie MeSH
• Názvy látek
• arsen MeSH
• látky znečišťující vzduch MeSH
• prach MeSH
• těžké kovy MeSH