Berry Kristin H, Christopher Mary M, Jacobson Elliott R
U.S. Geological Survey, Western Ecological Research Center, Reno, NV, United States.
Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States.
Front Vet Sci. 2024 Nov 21;11:1481367. doi: 10.3389/fvets.2024.1481367. eCollection 2024.
Desert tortoise () populations have continued to decline due to infectious and other diseases, predation, and habitat alteration. The potential contribution of minerals and heavy metals to tortoise health and susceptibility to disease remains uncertain.
The objective of this study was to evaluate the results of elemental analysis on trace minerals, macrominerals, and heavy metals in scute keratin, kidney, and liver from ill and dying desert tortoises salvaged for necropsy between 1993 and 2000.
Salvaged tortoises were categorized by size (adult, juvenile), geographic location, and primary disease based on necropsy findings. A subset of tortoises that were injured or killed by vehicular trauma or predation but with no notable pathologic abnormalities was used for comparison with diseased tortoises. The panel of elements was analyzed in scute keratin, kidney, and liver samples by inductively-coupled plasma spectrometry and atomic absorption spectrophotometry.
Necropsies were done on 46 tortoises, including 9 juveniles, salvaged from 5 regions in the Colorado and Mojave Deserts of California. Primary diseases were cutaneous dyskeratosis ( = 9), infection/inflammation ( = 8), malnutrition ( = 7), mycoplasmosis ( = 5), and urolithiasis ( = 3); 14 tortoises died of trauma. Concentrations of elements differed by tissue, size, desert region, and disease status ( < 0.05). Tortoises with cutaneous dyskeratosis had higher Se concentrations, primarily in keratin and liver, than tortoises with other diseases ( < 0.001). Juveniles were more likely than adults to have high Pb, Sn, and Zn levels ( < 0.05). All tortoises had detectable levels of more than one potentially toxic heavy metal, including As, Cd, Cr, Hg, Ni, Pb, Sn, and V.
Potentially toxic elements are frequently found in tissues from tortoises in desert regions of California, with higher concentrations in diseased tortoises. Metal exposure from soils, mining, historic and ongoing military activities, and other human activities could increase susceptibility to disease in desert tortoises.
由于传染病及其他疾病、捕食和栖息地改变，沙漠陆龟（）种群数量持续下降。矿物质和重金属对陆龟健康及疾病易感性的潜在影响仍不确定。
本研究的目的是评估1993年至2000年间为尸检而救助的患病及濒死沙漠陆龟的盾片角质、肾脏和肝脏中微量矿物质、常量矿物质和重金属的元素分析结果。
根据尸检结果，将救助的陆龟按大小（成年、幼年）、地理位置和主要疾病进行分类。选取一部分因车辆撞击或捕食而受伤或死亡但无明显病理异常的陆龟，与患病陆龟进行比较。通过电感耦合等离子体质谱法和原子吸收分光光度法分析盾片角质、肾脏和肝脏样本中的元素。
对从加利福尼亚州科罗拉多沙漠和莫哈韦沙漠5个地区救助的46只陆龟进行了尸检，其中包括9只幼年陆龟。主要疾病有皮肤角化不良（=9）、感染/炎症（=8）、营养不良（=7）、支原体病（=5）和尿石症（=3）；14只陆龟死于外伤。元素浓度因组织、大小、沙漠区域和疾病状态而异（<0.05）。患有皮肤角化不良的陆龟，主要是角质和肝脏中的硒浓度高于患有其他疾病的陆龟（<0.001）。幼年陆龟比成年陆龟更易出现高铅、高锡和高锌水平（<0.05）。所有陆龟体内均可检测到不止一种潜在有毒重金属，包括砷、镉、铬、汞、镍、铅、锡和钒。
在加利福尼亚州沙漠地区的陆龟组织中经常发现潜在有毒元素，患病陆龟中的浓度更高。土壤、采矿、历史及正在进行的军事活动和其他人类活动导致的金属暴露可能会增加沙漠陆龟对疾病的易感性。
