title: Gastropod (Otala lactea) shell nanomechanical and structural characterization as a biomonitoring tool for dermal and dietary exposure to a model metal.
abstract: Metallic tungsten (W) was initially assumed to be environmentally benign and a green alternative to lead. However, subsequent investigations showed that fishing weights and munitions containing elemental W can fragment and oxidize into complex monomeric and polymeric tungstate (WO4) species in the environment; this led to increased solubility and mobility in soils and increased bioaccumulation potential in plant and animal tissues. Here we expand on the results of our previous research, which examined tungsten toxicity, bioaccumulation, and compartmentalization into organisms, and present in this research that the bioaccumulation of W was related to greater than 50% reduction in the mechanical properties of the snail (Otala lactea), based on depth-sensing nanoindentation. Synchrotron-based X-ray fluorescence maps and X-ray diffraction measurements confirm the integration of W in newly formed layers of the shell matrix with the observed changes in shell biomechanical properties, mineralogical composition, and crystal orientation. With further development, this technology could be employed as a biomonitoring tool for historic metals contamination since unlike the more heavily studied bioaccumulation into soft tissue, shell tissue does not actively eliminate contaminants.
authors: University of Alabama, Department of Mechanical Engineering, Box 870276, Tuscaloosa, AL 35406, USA. Electronic address: pallison@eng.ua.edu.
authors: Paul G
authors: PG
authors: Allison
authors: US Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Rd, Vicksburg, MS 39180, USA.
authors: Jennifer M
authors: JM
authors: Seiter
authors: University of Puerto Rico at Mayaguez, Department of Mechanical Engineering, 259 Boulevard Alfonso Valdes, Mayaguez, PR 00681, USA.
authors: Alfredo
authors: A
authors: Diaz
authors: US Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Rd, Vicksburg, MS 39180, USA.
authors: James H
authors: JH
authors: Lindsay
authors: US Army Engineer Research and Development Center, Geotechnical and Structures Laboratory, 3909 Halls Ferry Rd, Vicksburg, MS 39180, USA.
authors: Robert D
authors: RD
authors: Moser
authors: National Synchrotron Light Source at Brookhaven National Laboratory, Beamline X27A, Bldg 725, Upton, NY 11973, USA.
authors: Ryan V
authors: RV
authors: Tappero
authors: US Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Rd, Vicksburg, MS 39180, USA.
authors: Alan J
authors: AJ
authors: Kennedy
mesh_terms: D060105:Animal Shells / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D004032:Diet / Q000009:adverse effects; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity; D049851:Gastropoda / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D055595:Mechanical Phenomena; D036103:Nanotechnology / Q000379:methods*; D012867:Skin / Q000187:drug effects / Q000378:metabolism; D014414:Tungsten / Q000378:metabolism* / Q000633:toxicity
chemical_list: D004785:Environmental Pollutants; D014414:Tungsten
keywords: Biomonitoring; Gastropod; Heavy Metal; Nanoindentation; Synchrotron; X-ray