title: Oral bioaccessibility of inorganic contaminants in waste dusts generated by laterite Ni ore smelting.
abstract: 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.
authors.affiliation: Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, Prague 2, 128 43, Czech Republic. ettler@natur.cuni.cz.
authors.forename: Vojtěch
authors.initials: V
authors.lastname: Ettler
authors.affiliation: Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, Prague 2, 128 43, Czech Republic.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Polák
authors.affiliation: Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, Prague 2, 128 43, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Mihaljevič
authors.affiliation: UMR 8148 GEOPS, Univ. Paris-Sud, CNRS, Université Paris-Saclay, Rue du Belvédère, Bât. 504, 91405, Orsay, France.|University of Brasilia, UnB, Campus Universitario Darcy Ribeiro, Brasilia, DF, 70910-970, Brazil.
authors.forename: Gildas
authors.initials: G
authors.lastname: Ratié
authors.affiliation: University of Brasilia, UnB, Campus Universitario Darcy Ribeiro, Brasilia, DF, 70910-970, Brazil.
authors.forename: Jérémie
authors.initials: J
authors.lastname: Garnier
authors.affiliation: UMR 8148 GEOPS, Univ. Paris-Sud, CNRS, Université Paris-Saclay, Rue du Belvédère, Bât. 504, 91405, Orsay, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Quantin
mesh_terms: D000284:Administration, Oral; D001938:Brazil; D002857:Chromium / Q000032:analysis; D060729:Coal Ash / Q000032:analysis*; D003035:Cobalt / Q000032:analysis; D004391:Dust / Q000032:analysis*; D004781:Environmental Exposure; D005750:Gastric Juice; D006256:Hazardous Waste / Q000032:analysis*; D006801:Humans; D007220:Industrial Waste; D007287:Inorganic Chemicals / Q000008:administration & dosage*; D008669:Metallurgy; D008954:Models, Biological; D009532:Nickel / Q000032:analysis*; D012037:Refuse Disposal / Q000379:methods
chemical_list: D060729:Coal Ash; D004391:Dust; D006256:Hazardous Waste; D007220:Industrial Waste; D007287:Inorganic Chemicals; D002857:Chromium; D003035:Cobalt; D009532:Nickel
keywords: Bioaccessibility; Dust; Fly ash; Laterite; Ni smelting; Slag