Trace element biodistribution in the American alligator ( Alligator mississippiensis)

Nilsen, Frances M.; Kassim, Brittany L.; Delaney, J. Patrick; Lange, Ted; Brunell, Arnold M.; Guillette, Louis J.; Long, Stephen E.; Schock, Tracey B.

doi:10.1016/j.chemosphere.2017.04.102

Cited by 29 publications

(26 citation statements)

References 39 publications

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“…The mean blood Pb concentrations observed in this study are within the range reported in the liver of adult alligators from other sites in Florida (35 ng/g–3400 ng/g), but lesser than the mean liver Pb concentration reported (8150 ng/g) for alligators from the Charleston, SC area (Horai et al, 2014; Campbell et al, 2010). The mean Pb concentrations in blood observed in alligators in this study are comparable to historic muscle tissue samples from alligators across Florida range from 40 ng/g to 120 ng/g Pb (Nilsen et al, 2017b; Lance et al, 2006). Using the known Pb biodistribution information we can extrapolate that the alligators samples in this study are likely to have lesser Pb concentration in their muscle and liver tissue than those previously reported, since the blood Pb concentrations from our study are comparable to previously reported muscle and liver Pb concentrations, and therefore the alligators in this study may be less exposed to Pb than alligators at other sites (Nilsen et al, 2017b).…”

Section: Discussionsupporting

confidence: 66%

“…The mean Pb concentrations in blood observed in alligators in this study are comparable to historic muscle tissue samples from alligators across Florida range from 40 ng/g to 120 ng/g Pb (Nilsen et al, 2017b; Lance et al, 2006). Using the known Pb biodistribution information we can extrapolate that the alligators samples in this study are likely to have lesser Pb concentration in their muscle and liver tissue than those previously reported, since the blood Pb concentrations from our study are comparable to previously reported muscle and liver Pb concentrations, and therefore the alligators in this study may be less exposed to Pb than alligators at other sites (Nilsen et al, 2017b). Routinely monitoring the Pb concentrations in blood samples could provide greater details regarding the baseline blood Pb concentrations for alligators in this region and will provide the opportunity to observe temporal changes in exposure.…”

Section: Discussionsupporting

confidence: 66%

“…The Pb blood concentrations observed in alligators in this study (range of mean concentrations = 33–906 ng/g, Table 1) are unable to be directly compared to other alligator populations, as previous studies do not report Pb in blood samples. However, the known biodistribution of Pb in alligators is such that muscle and liver tissue both have a lesser Pb concentration compared to blood (Nilsen et al, 2017b). The mean blood Pb concentrations observed in this study are within the range reported in the liver of adult alligators from other sites in Florida (35 ng/g–3400 ng/g), but lesser than the mean liver Pb concentration reported (8150 ng/g) for alligators from the Charleston, SC area (Horai et al, 2014; Campbell et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…The American alligator (Alligator mississippiensis) is a keystone predator that is critical to the balanced structure and function of wetlands throughout the southeastern U.S., directly connecting alligators to the health of the wetland ecosystem (Palmer and Mazzotti, 2004; Mazzotti et al, 2009; Bondavalli and Ulanowicz, 1999; Kushlan, 1974; Rosenblatt and Heithaus, 2011). The toxic trace elements have continually been reported in the tissues of alligators sampled across Florida and South Carolina (Nilsen et al, 2017b; Burger et al, 2000; Horai et al, 2014; Delany et al, 1988; Campbell et al, 2010; Yanochko et al, 1997). The long lifespan, broad diet, and relatively strong site fidelity have allowed alligators to be used in monitoring the effects of contaminants both at the population and individual levels for decades (Nilsen et al, 2017b; Wilkinson et al, 2016; Hord et al, 1990; Lange et al, 2000; Delany et al, 1988; Milnes and Guillette, 2008; Guillette et al, 2000; Gunderson et al, 2003, 2004, 2006; Hamlin et al, 2010; Elsey et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…The toxic trace elements have continually been reported in the tissues of alligators sampled across Florida and South Carolina (Nilsen et al, 2017b; Burger et al, 2000; Horai et al, 2014; Delany et al, 1988; Campbell et al, 2010; Yanochko et al, 1997). The long lifespan, broad diet, and relatively strong site fidelity have allowed alligators to be used in monitoring the effects of contaminants both at the population and individual levels for decades (Nilsen et al, 2017b; Wilkinson et al, 2016; Hord et al, 1990; Lange et al, 2000; Delany et al, 1988; Milnes and Guillette, 2008; Guillette et al, 2000; Gunderson et al, 2003, 2004, 2006; Hamlin et al, 2010; Elsey et al, 2008). The alligator has a varied diet consisting of both vertebrate and invertebrates but is comprised mostly of fish (Rice, 2004; Rice et al, 2007; Delany et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Examining toxic trace element exposure in American alligators

Nilsen

Bowden

Rainwater

et al. 2019

Environment International

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Toxic trace element exposure occurs through release of the ubiquitous and naturally occurring elements arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg). The unique environmental conditions of the wetland ecosystems along the southeastern Atlantic coast of the United States lead to the accumulation of Hg which is greater than in most other ecosystems in the country. There are also point sources of As, Cd, and Pb in this region. To effectively monitor trace element concentrations, and consequently the potential human exposure, accessible local sentinel species are needed. In this study, concentrations of As, Cd, Pb, Hg and six other trace elements (Al, Ni, Cu, Zn, Se, Mo) were examined in American alligators (Alligator mississippiensis) from seven wetland sites in South Carolina and Florida and assessed for their utility as a sentinel species for human trace element exposure. Alligators were chosen as a potential sentinel as they share a common exposure with the local human population through their aquatic diet, and they are directly consumed commercially and through recreation hunting in this region. Sex was significantly related to the concentration of Zn, Mo, and Al, but not As, Pb, Hg, Cd, Se, or Cu. Site specific differences in element concentrations were observed for As, Pb, Hg, Cd, Se, Zn, and Mo. Size/age was significantly related to the element Hg and Pb concentrations observed. The observed concentration ranges for the four toxic elements, As (6–156 ng/g), Cd (0.3–1.3 ng/g), Pb (3–4872 ng/g), and Hg (39–2765 ng/g), were comparable to those previously reported in diverse human populations. In this region alligators are hunted recreationally and consumed by the local community, making them a vehicle of direct human toxic element exposure. We propose that the similarity in As, Cd, Pb, and Hg concentrations between alligators observed in this study and humans underscores how alligators can serve as a useful sentinel species for toxic element exposure.

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Section: Discussionsupporting

confidence: 66%

Section: Discussionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Examining toxic trace element exposure in American alligators

Nilsen

Bowden

Rainwater

et al. 2019

Environment International

Self Cite

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Integrating Mercury Concentrations in American Alligators (Alligator mississippiensis) with Hunter Consumption Surveys to Estimate Exposure Risk

Kojima

Tuberville

Parrott

2023

Enviro Toxic and Chemistry

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Mercury is a naturally occurring element but is also considered a widespread contaminant due to global anthropogenic activity. Even in moderate amounts, mercury (Hg) is an established neurotoxin and is associated with a range of adverse outcomes both in humans and wildlife. Humans in the United States are most commonly exposed to Hg through contaminated food or drinking water, and the consumption of game species, particularly those occupying higher trophic levels, has the potential to expose hunters to high concentrations of Hg. In the present study, we determined Hg concentrations in tail muscle and blood from American alligators (Alligator mississippiensis) inhabiting a region (Savannah River Site, SC, USA) with known Hg contamination. We then integrated these data with alligator harvest records and previously published surveys of alligator meat consumption patterns to estimate potential exposure risk. We found that the average Hg concentrations in tail muscle (1.34 mg/kg, wet wt) from sampled alligators exceeded the recommended threshold for Hg exposure based on the World Health Organization's guidelines (0.5 mg/kg, wet wt). In addition, based on regional consumption patterns reported for both adults and children, we estimated Hg exposures (x Adult ¯= 0.419 µg/kg/day, x Child ¯= 2.24 µg/kg/day) occurring well above the US Environmental Protection Agency methylmercury reference dose of 0.1 μg/kg/day. Although the two reservoirs sampled in the present study are not currently open to alligator hunting, they are connected to waters that are publicly accessible, and the extent of alligator mobility across these sites is not known. Together, the findings reported in the present study further demonstrate the need for active monitoring of Hg concentrations in game species, which can convey substantial exposure risks to the public.

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Nondestructive Evaluation of Metal Bioaccumulation and Biochemical Biomarkers in Blood of Broad‐Snouted Caiman (Caiman latirostris) from Northeastern Brasil

dos Santos,

Mariz Jr.,

Mascarenhas‐Júnior

et al. 2024

Enviro Toxic and Chemistry

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Studies on the bioaccumulation and toxicity of contaminants in Crocodylians are scarce. We evaluated alterations in concentrations of the nondestructive biomarkers butyrylcholinesterase (BChE), glutathione‐S‐transferase (GST), superoxide dismutase (SOD), and reduced glutathione (GSH), together with bioaccumulation of the metals iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), chronium (Cr), aluminium (Al), and lead (Pb) in Caiman latirostris captured in Tapacurá Reservoir (TR; São Lourenço da Mata, Pernambuco, Brasil), in urbanized areas of Pernambuco State (UA; Brasil) and from the AME Brasil caiman farm (AF; Marechal Deodoro, Alagoas, Brasil); the latter was used as a potential reference with low levels of contamination. For metal analysis, 500 µL of blood was digested in 65% HNO3 and 30% H2O2. The samples were analyzed by inductively coupled plasma–optical emission spectrometry. For analysis of biomarkers, an aliquot of blood was centrifuged to obtain plasma in which biochemical assays were performed. Blood concentrations of metals analyzed in animals from AF were lower compared with TR and UA, confirming that animals from the caiman farm could be used as references with low levels of contamination. Iron, Cu, Mn, Al, and Pb exceeded toxic levels for other vertebrates in animals from TR and UA. Butyrylcholinesterase activity showed significant reduction in adults from UA and TR compared with AF. An increase in the activity of GST and GSH, in adults of TR and UA in relation to AF, was verified. Superoxide dismutase activity showed a significant reduction in adults of TR in relation to AF, and the concentrations of Cu and Mn were negatively correlated with SOD activity. Animals from UA and TR showed greater concentrations of the analyzed metals compared with reference animals, and changes in biomarkers were seen, confirming the potential of these nondestructive chemical and biological parameters in blood of C. latirostris for biomonitoring of pollution. Environ Toxicol Chem 2024;00:1–18. © 2024 SETAC

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Trace element biodistribution in the American alligator ( Alligator mississippiensis)

Cited by 29 publications

References 39 publications

Examining toxic trace element exposure in American alligators

Examining toxic trace element exposure in American alligators

Integrating Mercury Concentrations in American Alligators (Alligator mississippiensis) with Hunter Consumption Surveys to Estimate Exposure Risk

Nondestructive Evaluation of Metal Bioaccumulation and Biochemical Biomarkers in Blood of Broad‐Snouted Caiman (Caiman latirostris) from Northeastern Brasil

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