TY - JOUR
T1 - Heavy metal concentrations in mojave desert tortoises (Gopherus agassizii) related to a mitigation translocation project, Ivanpah Valley, California, USA
AU - Cohn, Brian
AU - Wallace, Bryan
AU - Grouios, Chris
AU - Dickson, Brett
AU - Scherer, Rick
AU - Kissel, Amanda
AU - Gray, Miranda E.
AU - Jackson, T. G.
N1 - Funding Information:
We thank Kimberleigh J. Field, Roy C. Averill-Murray, and Linda J. Allison of the Desert Tortoise Recovery Office, U.S. Fish and Wildlife Service, for their support and assistance with project approval and permission. We are grateful to the following field biologists and researchers who were integral in developing the methods for and/or executing the collection and preservation of the samples for this project (cited in alphabetical order): Wayne Ball, Imogen Daly, Elijah Davidson, Shannon DiRuzzo, Cynthia Furman, Max Havelka, Kelly Herbinson, John Hillman, Craig Himmelwright, Dr. LaDeana Jeane, George Keyes Jr., Shawn Lindey, Chandra Llewellyn, Jay Meyers, Dr. LeeAnn Munk, Laura Pavliscak, Amanda Scheib, Liz Smith, Nicole Stephens, Myles Traphagen, Jeffery Valentine, Mercy Vaughn, Bruce Weise and Peter Woodman. The designated biologists Amanda Scheib and Bruce Weise were instrumental in supporting the project to fruition. Andreas Lehner and John Buchweitz of the Diagnostic Center for Population and Animal Health at Michigan State University, East Lansing, USA, provided guidance for the collection of the DBS samples and analytical support. Birgit Hagerdorn (formerly) of the Applied Science, Engineering and Technology Lab at the University of Alaska, Anchorage, USA, provided lab support and conducted the analytical portion for all soil samples. Data collection and analyses were funded by NRG Energy Services, Princeton, New Jersey, USA, Google Inc., Mountain View, California, USA, and BrightSource Energy, Oakland, California, USA through three limited liability companies: Solar Partners I, Solar Partners II, and Solar Partners VIII. The ISEGS is operated by NRG Energy Services. The funder played no role in the study design and analysis, interpretation of data, writing of the manuscript, or decision to submit the article for publication. This study was conducted under the Biological Opinion 8-8-10-F-24R of the U.S. Fish and Wildlife Service (USFWS; Biological Opinion on BrightSource Energy’s Ivanpah Solar Electric Generating System Project). Authorized Biologists following USFWS protocols and health assessment procedures conducted all activities including but not limited to Desert Tortoise handling, health assessments, and blood sampling.
Publisher Copyright:
© 2021. Brian Cohn All Rights Reserved.
PY - 2021/4
Y1 - 2021/4
N2 - The Mojave Desert Tortoise (Gopherus agassizii) is listed as threatened under the U.S. Endangered Species Act because of subsidized predation by other species, loss and degradation of its habitat owing to human activities, and disease. Potential exposure of toxic substances on G. agassizii that possibly impede recovery, however, have not been thoroughly investigated. To quantify concentrations of several heavy metals and examine possible adverse effects of heavy metal toxicity on G. agassizii, we analyzed blood samples using the Dried Blood Spot (DBS) method and soil samples from their locations in the Ivanpah Valley, California, USA. In most cases, heavy metal concentrations in blood never or rarely exceeded minimum detection levels (typically, 0%-7% of samples in a given season). In soils, several heavy metals (e.g., arsenic, lead, and thorium) exceed average crust composition, but none exceeded soil health guidelines. Furthermore, lead, selenium, iron, and arsenic concentrations were lower than, or within, published ranges for turtles, reptiles, and other vertebrates. We found a positive relationship between survival and selenium and iron concentrations but no relationship between metal concentrations and health indicators such as body condition and disease prevalence. Our results suggest that G. agassizii in our study area were not exposed to toxic levels or suffered adverse effects of heavy metals. The DBS method is minimally invasive and effective for the collection of blood samples from G. agassizii. Further analyses should explore how well samples collected by the DBS method reflect metal concentrations in other tissues.
AB - The Mojave Desert Tortoise (Gopherus agassizii) is listed as threatened under the U.S. Endangered Species Act because of subsidized predation by other species, loss and degradation of its habitat owing to human activities, and disease. Potential exposure of toxic substances on G. agassizii that possibly impede recovery, however, have not been thoroughly investigated. To quantify concentrations of several heavy metals and examine possible adverse effects of heavy metal toxicity on G. agassizii, we analyzed blood samples using the Dried Blood Spot (DBS) method and soil samples from their locations in the Ivanpah Valley, California, USA. In most cases, heavy metal concentrations in blood never or rarely exceeded minimum detection levels (typically, 0%-7% of samples in a given season). In soils, several heavy metals (e.g., arsenic, lead, and thorium) exceed average crust composition, but none exceeded soil health guidelines. Furthermore, lead, selenium, iron, and arsenic concentrations were lower than, or within, published ranges for turtles, reptiles, and other vertebrates. We found a positive relationship between survival and selenium and iron concentrations but no relationship between metal concentrations and health indicators such as body condition and disease prevalence. Our results suggest that G. agassizii in our study area were not exposed to toxic levels or suffered adverse effects of heavy metals. The DBS method is minimally invasive and effective for the collection of blood samples from G. agassizii. Further analyses should explore how well samples collected by the DBS method reflect metal concentrations in other tissues.
KW - Arsenic
KW - Cutaneous dyskeratosis
KW - Dried blood spot
KW - Endangered species
KW - Iron
KW - Lead
KW - Selenium
KW - Upper respiratory tract disease
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M3 - Article
AN - SCOPUS:85105573002
SN - 2151-0733
VL - 16
SP - 128
EP - 141
JO - Herpetological Conservation and Biology
JF - Herpetological Conservation and Biology
IS - 1
ER -