Mineralogy affects geoavailability, bioaccessibility and bioavailability of zinc.
We correlated mineralogical and particle characteristics of Zn-containing particles with Zn geoavailability, bioaccessibility, and bioavailability following gavage and intranasal (IN) administration in rats. We compared samples of Zn/Pb mine waste and five pulverized pure-phase Zn minerals (<38 μm). Particles were neutron-activated to produce radioactive (65)Zn. We assessed geoavailability using sequential extractions and bioaccessibility using in vitro extraction tests simulating various pH and biological conditions. Zn in vivo bioavailability and in vitro bioaccessibility decreased as follows: mine waste > hydrozincite > hemimorphite > zincite ≈ smithsonite >> sphalerite. We found significant correlations among geoavailability, bioaccessibility and bioavailability. In particular, Zn bioavailability post-gavage and post-IN was significantly correlated with bioaccessibility in simulated phagolysosomal fluid and gastric fluid. These data indicate that solid phase speciation influences biological uptake of Zn and that in vitro tests can be used to predict Zn bioavailability in exposure assessment and effective remediation design.
Program in Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115, USA. Electronic address: rmolina@hsph.harvard.edu.
Ramon M
RM
Molina
Laurel A
LA
Schaider
Thomas C
TC
Donaghey
James P
JP
Shine
Joseph D
JD
Brain
D000818:Animals; D008297:Male; D008903:Minerals / Q000737:chemistry* / Q000378:metabolism; D008906:Mining; D051381:Rats; D017207:Rats, Sprague-Dawley; D012989:Soil Pollutants / Q000737:chemistry* / Q000378:metabolism; D015032:Zinc / Q000737:chemistry* / Q000378:metabolism
D008903:Minerals; D012989:Soil Pollutants; D015032:Zinc
Bioaccessibility; Bioavailability; Metal speciation; Physiologically-based extraction tests; Sequential extractions; Zinc