title: Assessing the Dietary Bioavailability of Metals Associated with Natural Particles: Extending the Use of the Reverse Labeling Approach to Zinc.
abstract: We extend the use of a novel tracing technique to quantify the bioavailability of zinc (Zn) associated with natural particles using snails enriched with a less common Zn stable isotope. Lymnaea stagnalis is a model species that has relatively fast Zn uptake rates from the dissolved phase, enabling their rapid enrichment in67Zn during the initial phase of labeling. Isotopically enriched snails were subsequently exposed to algae mixed with increasing amounts of metal-rich particles collected from two acid mine drainage impacted rivers. Zinc bioavailability from the natural particles was inferred from calculations of66Zn assimilation into the snail's soft tissues. Zinc assimilation efficiency (AE) varied from 28% for the Animas River particles to 45% for the Snake River particles, indicating that particle-bound, or sorbed Zn, was bioavailable from acid mine drainage wastes. The relative binding strength of Zn sorption to the natural particles was inversely related to Zn bioavailability; a finding that would not have been possible without using the reverse labeling approach. Differences in the chemical composition of the particles suggest that their geochemical properties may influence the extent of Zn bioavailability.
authors.affiliation: U.S. Geological Survey, MS 496, 345 Middlefield Road Menlo Park, California 94025, United States.
authors.forename: Marie-Noële
authors.identifier: 0000-0003-0346-3580
authors.initials: MN
authors.lastname: Croteau
authors.affiliation: U.S. Geological Survey, MS 496, 345 Middlefield Road Menlo Park, California 94025, United States.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Cain
authors.affiliation: U.S. Geological Survey, MS 496, 345 Middlefield Road Menlo Park, California 94025, United States.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Fuller
mesh_terms: D000818:Animals; D001682:Biological Availability; D008670:Metals; D008906:Mining; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical; D015032:Zinc
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical; D015032:Zinc