title: Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: documenting the uptake of elemental toxicants.
abstract: The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.
authors.affiliation: Naval Air Warfare Center Weapons Division, Code 4T4230D, 1900 N. Knox Road Stop 6303, China Lake, CA 93555-6106, USA. michael.seltzer@navy.mil
authors.forename: Michaeld
authors.initials: M
authors.lastname: Seltzer
authors.forename: Kristinh
authors.initials: K
authors.lastname: Berry
mesh_terms: D000818:Animals; D001151:Arsenic / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D015386:Hazardous Substances / Q000032:analysis*; D007633:Keratins / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D009017:Morbidity; D009026:Mortality; D012015:Reference Standards; D013455:Sulfur / Q000032:analysis; D014131:Trace Elements / Q000032:analysis*; D014426:Turtles / Q000378:metabolism*; D015032:Zinc / Q000032:analysis
chemical_list: D004785:Environmental Pollutants; D015386:Hazardous Substances; D014131:Trace Elements; D007633:Keratins; D013455:Sulfur; D015032:Zinc; D001151:Arsenic