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Pérez-González E, Quintero-Borquez IP, Herrera-Moreno MN, Ley-Quiñónez CP, Polanco-Torres A, González-Ocampo HA, Llanes-Cárdenas O, Salomón-Soto VM. Detection of organochlorine pesticides in infertile eggs of crocodylus acutus from sinaloa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-32147-x. [PMID: 38374502 DOI: 10.1007/s11356-024-32147-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 01/18/2024] [Indexed: 02/21/2024]
Abstract
Environmental contaminants endanger human health and non-target organisms such as crocodiles (Crocodylus acutus) that live in aquatic bodies surrounding agricultural areas. Due to their intrinsic characteristics, these organisms could be bioaccumulating and transmitting organochlorine pesticides (OCs) to their eggs. The objectives of this study were to determine the OCs in infertile eggs of C. acutus from Sinaloa and their correlation with the morphometric characteristics (MC), and to perform a preliminary estimate of the ecological risk due to the presence of pesticides using the PERPEST model. In June 2022, 76 infertile eggs (Ie) were collected: 57 from wild areas (Wa) and 19 from a crocodile farm (CSMf). Determination of OC in Ie was performed according to the USEPA method 8081b, modified. The observed percentages of Ie in Wa were 31.48% and 21.33% in CSMf. Twenty OCs were detected in the Ie, where dieldrin recorded the highest average concentration in Wa (6542.6 ng/g), and endosulfan-II in the CSMf (2172.8 ng/g). Bad negative and positive correlations were observed between OCs and MC, standing out the correlations between endosulfan-II and %Ie (-0.688) in the Wa, Cedritos drain, and between endrin and the weight of Ie (0.786) of the CSMf. The evaluation of the ecological risks of the aquatic environment due to the presence of OCs follow the sequence cyclodienes > aromatic > alicyclic hydrocarbons. A potential risk to the endocrine health of the species C. acutus was observed. Crocodiles are excellent biological models for monitoring the effects of OCs.
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Affiliation(s)
- Ernestina Pérez-González
- Departamento de Medio Ambiente, Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional unidad Sinaloa (IPN-CIIDIR-Sinaloa), Guasave, Sinaloa, Mexico.
- Centro de Estudios "Justo Sierra", Graduate Program, Surutato, Badiraguato, Sinaloa, Mexico.
| | | | - María Nancy Herrera-Moreno
- Departamento de Medio Ambiente, Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional unidad Sinaloa (IPN-CIIDIR-Sinaloa), Guasave, Sinaloa, Mexico
| | - César Paul Ley-Quiñónez
- Departamento de Medio Ambiente, Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional unidad Sinaloa (IPN-CIIDIR-Sinaloa), Guasave, Sinaloa, Mexico
| | - Arturo Polanco-Torres
- Departamento de Medio Ambiente, Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional unidad Sinaloa (IPN-CIIDIR-Sinaloa), Guasave, Sinaloa, Mexico
| | - Héctor Abelardo González-Ocampo
- Departamento de Medio Ambiente, Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional unidad Sinaloa (IPN-CIIDIR-Sinaloa), Guasave, Sinaloa, Mexico
| | - Omar Llanes-Cárdenas
- Departamento de Medio Ambiente, Instituto Politécnico Nacional, Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional unidad Sinaloa (IPN-CIIDIR-Sinaloa), Guasave, Sinaloa, Mexico
| | - Víctor Manuel Salomón-Soto
- Centro de Estudios "Justo Sierra", Graduate Program, Surutato, Badiraguato, Sinaloa, Mexico
- Facultad de Biología, Universidad Autónoma de Sinaloa, Culiacan, Sinaloa, Mexico
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2
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Marlatt VL, Bayen S, Castaneda-Cortès D, Delbès G, Grigorova P, Langlois VS, Martyniuk CJ, Metcalfe CD, Parent L, Rwigemera A, Thomson P, Van Der Kraak G. Impacts of endocrine disrupting chemicals on reproduction in wildlife and humans. ENVIRONMENTAL RESEARCH 2022; 208:112584. [PMID: 34951986 DOI: 10.1016/j.envres.2021.112584] [Citation(s) in RCA: 54] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 06/14/2023]
Abstract
Endocrine disrupting chemicals (EDCs) are ubiquitous in aquatic and terrestrial environments. The main objective of this review was to summarize the current knowledge of the impacts of EDCs on reproductive success in wildlife and humans. The examples selected often include a retrospective assessment of the knowledge of reproductive impacts over time to discern how the effects of EDCs have changed over the last several decades. Collectively, the evidence summarized here within reinforce the concept that reproduction in wildlife and humans is negatively impacted by anthropogenic chemicals, with several altering endocrine system function. These observations of chemicals interfering with different aspects of the reproductive endocrine axis are particularly pronounced for aquatic species and are often corroborated by laboratory-based experiments (i.e. fish, amphibians, birds). Noteworthy, many of these same indicators are also observed in epidemiological studies in mammalian wildlife and humans. Given the vast array of reproductive strategies used by animals, it is perhaps not surprising that no single disrupted target is predictive of reproductive effects. Nevertheless, there are some general features of the endocrine control of reproduction, and in particular, the critical role that steroid hormones play in these processes that confer a high degree of susceptibility to environmental chemicals. New research is needed on the implications of chemical exposures during development and the potential for long-term reproductive effects. Future emphasis on field-based observations that can form the basis of more deliberate, extensive, and long-term population level studies to monitor contaminant effects, including adverse effects on the endocrine system, are key to addressing these knowledge gaps.
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Affiliation(s)
- V L Marlatt
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
| | - S Bayen
- Department of Food Science and Agricultural Chemistry, McGill University, Montreal, QC, Canada
| | - D Castaneda-Cortès
- Centre Eau Terre Environnement, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - G Delbès
- Centre Armand Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - P Grigorova
- Département Science et Technologie, Université TELUQ, Montréal, QC, Canada
| | - V S Langlois
- Centre Eau Terre Environnement, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - C J Martyniuk
- Center for Environmental and Human Toxicology, Department of Physiological Sciences, University of Florida, Gainesville, FL, United States
| | - C D Metcalfe
- School of Environment, Trent University, Trent, Canada
| | - L Parent
- Département Science et Technologie, Université TELUQ, Montréal, QC, Canada
| | - A Rwigemera
- Centre Armand Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - P Thomson
- Centre Eau Terre Environnement, Institut National de la Recherche Scientifique (INRS), Laval, QC, Canada
| | - G Van Der Kraak
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
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3
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Platt SG, Rainwater TR, McMurry ST. Fauna associated with the nests of Crocodylus moreletii and Crocodylus moreletii × acutus in Belize. J NAT HIST 2021. [DOI: 10.1080/00222933.2021.1895350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Steven G. Platt
- Wildlife Conservation Society - Myanmar Program, Yangon, Myanmar
| | - Thomas R. Rainwater
- Tom Yawkey Wildlife Center & Belle W. Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC, USA
| | - Scott T. McMurry
- Department of Integrative Biology, 521 Life Sciences West, Oklahoma State University, Stillwater, OK, USA
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4
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Tavalieri YE, Galoppo GH, Canesini G, Luque EH, Muñoz-de-Toro MM. Effects of agricultural pesticides on the reproductive system of aquatic wildlife species, with crocodilians as sentinel species. Mol Cell Endocrinol 2020; 518:110918. [PMID: 32619582 DOI: 10.1016/j.mce.2020.110918] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 11/15/2022]
Abstract
Agricultural pesticides represent a significant class of endocrine-disrupting chemicals (EDCs) to which non-target organisms around the world are constantly exposed. Laboratory studies have found strong evidence showing the endocrine-disruptive potential of these pesticides at environmentally relevant exposure levels. Since the field of endocrine disruption continues to grow in richness and complexity, this review aims to provide an update on the effects of two agricultural pesticides that act as EDCs: atrazine and endosulfan. We will focus mainly on the effects on crocodilians due to their worldwide occurrence in tropical and sub-tropical wetland ecosystems and their ecological and physiological features, which render them vulnerable to exposure to pesticides with endocrine-disrupting action at all life stages. The results here reviewed provide important insights into the effects of hormonally active agricultural pesticides at cellular, tissue, and organ levels in the reproductive system of crocodiles. A better understanding of the effects of exposure to environmentally relevant doses of EDCs on the reproductive system of crocodilians will contribute to protect and improve the health of both wildlife species and humans.
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Affiliation(s)
- Y E Tavalieri
- Laboratorio de EcoFisioPatología, Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - G H Galoppo
- Laboratorio de EcoFisioPatología, Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - G Canesini
- Laboratorio de EcoFisioPatología, Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - E H Luque
- Laboratorio de EcoFisioPatología, Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - M M Muñoz-de-Toro
- Laboratorio de EcoFisioPatología, Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
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5
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Somaweera R, Nifong J, Rosenblatt A, Brien ML, Combrink X, Elsey RM, Grigg G, Magnusson WE, Mazzotti FJ, Pearcy A, Platt SG, Shirley MH, Tellez M, Ploeg J, Webb G, Whitaker R, Webber BL. The ecological importance of crocodylians: towards evidence‐based justification for their conservation. Biol Rev Camb Philos Soc 2020; 95:936-959. [DOI: 10.1111/brv.12594] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 12/27/2022]
Affiliation(s)
- Ruchira Somaweera
- CSIRO Health and Biosecurity Floreat WA 6014 Australia
- School of Biological Sciences, University of Western Australia Crawley WA 6009 Australia
| | - James Nifong
- IFAS‐Fort Lauderdale Research & Education Center, University of Florida Fort Lauderdale FL 33314 USA
| | - Adam Rosenblatt
- University of North Florida 1 UNF Drive, Jacksonville FL 32224 USA
| | - Mathew L. Brien
- Queensland Parks and WildlifeDepartment of Environment and Science Cairns QLD 4870 Australia
| | - Xander Combrink
- Department of Nature ConservationTshwane University of Technology Pretoria South Africa
| | - Ruth M. Elsey
- Louisiana Department of Wildlife and Fisheries Rockefeller Wildlife Refuge Grand Chenier LA 70643 USA
| | - Gordon Grigg
- School of Biological SciencesUniversity of Queensland St Lucia QLD 4072 Australia
| | - William E. Magnusson
- Coordenação da Biodiversidade, Instituto Nacional da Pesquisas da Amazônia Manaus 69067 Brazil
| | - Frank J. Mazzotti
- Department of Wildlife Ecology and ConservationEverglades Research and Education Center, University of Florida Gainesville FL 32603 USA
| | - Ashley Pearcy
- Section for Ecoinformatics and Biodiversity, Department of BioScienceAarhus University Aarhus Denmark
| | - Steven G. Platt
- Wildlife Conservation Society ‐ Myanmar Program Yangon Myanmar
| | - Matthew H. Shirley
- Tropical Conservation InstituteFlorida International University Miami FL 33181 USA
| | | | - Jan Ploeg
- Australian National Centre for Ocean Resources and Security, Innovation Campus, University of Wollongong Wollongong NSW 2522 Australia
| | - Grahame Webb
- Wildlife Management International Karama NT 0812 Australia
- Research Institute for the Environment and Livelihoods, Charles Darwin University Casuarina NT 0810 Australia
| | - Rom Whitaker
- The Madras Crocodile Bank Trust & Centre for Herpetology Mahabalipuram 603104 India
| | - Bruce L. Webber
- CSIRO Health and Biosecurity Floreat WA 6014 Australia
- School of Biological Sciences, University of Western Australia Crawley WA 6009 Australia
- Western Australian Biodiversity Science Institute Perth WA 6000 Australia
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6
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Somaweera R, Brien ML, Sonneman T, Didham RK, Webber BL. Absence of evidence is not evidence of absence: Knowledge shortfalls threaten the effective conservation of freshwater crocodiles. Glob Ecol Conserv 2019. [DOI: 10.1016/j.gecco.2019.e00773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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7
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Alarcón R, Varayoud J, Luque EH, Milesi MM. Effect of neonatal exposure to endosulfan on myometrial adaptation during early pregnancy and labor in rats. Mol Cell Endocrinol 2019; 491:110435. [PMID: 31029737 DOI: 10.1016/j.mce.2019.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/13/2019] [Accepted: 04/22/2019] [Indexed: 12/28/2022]
Abstract
Proper myometrial adaptation during gestation is crucial for embryo implantation, pregnancy maintenance and parturition. Previously, we reported that neonatal exposure to endosulfan alters uterine development and induces implantation failures. The present work investigates the effects of endosulfan exposure on myometrial differentiation at the pre-implantation period, and myometrial activation during labor. Newborn female rats were s.c. injected with corn oil (vehicle) or 600 μg/kg/day of endosulfan (Endo600) on postnatal days (PND) 1, 3, 5 and 7. On PND90, the rats were mated to evaluate: i) the myometrial differentiation on gestational day 5 (GD5, pre-implantation period), by assessment myometrial histomorphology, smooth muscle cells (SMCs) proliferation, and expression of proteins involved in myometrial adaptation for embryo implantation (steroid receptors, Wnt7a and Hoxa10); ii) the timing of parturition and myometrial activation during labor by determining the uterine expression of contraction-associated genes (oxytocin receptor, OTXR; prostaglandin F2α receptor, PTGFR and connexin-43, Cx-43). Endosulfan decreased the thickness of both myometrial layers, with a concomitant decrease in the collagen remodeling. Blood vessels relative area in the interstitial connective tissue between muscle layers was also decreased. Endo600 group showed lower myometrial proliferation in association with a downregulation of Wnt7a and Hoxa10. Although in all females labor occurred on GD23, the exposure to endosulfan altered the timing of parturition, by inducing advancement in the initiation of labor. This alteration was associated with an increased uterine expression of OTXR, PTGFR and Cx-43. In conclusion, neonatal exposure to endosulfan produced long-term effects affecting myometrial adaptation during early pregnancy and labor. These alterations could be associated with the aberrant effects of endosulfan on the implantation process and the timing of parturition.
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Affiliation(s)
- Ramiro Alarcón
- Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina; Cátedra de Fisiología Humana, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Jorgelina Varayoud
- Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina; Cátedra de Fisiología Humana, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Enrique H Luque
- Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina; Cátedra de Fisiología Humana, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - María M Milesi
- Instituto de Salud y Ambiente del Litoral (ISAL, UNL-CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina; Cátedra de Fisiología Humana, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
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8
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Buah-Kwofie A, Humphries MS, Combrink X, Myburgh JG. Accumulation of organochlorine pesticides in fat tissue of wild Nile crocodiles (Crocodylus niloticus) from iSimangaliso Wetland Park, South Africa. CHEMOSPHERE 2018; 195:463-471. [PMID: 29274992 DOI: 10.1016/j.chemosphere.2017.12.084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 12/10/2017] [Accepted: 12/12/2017] [Indexed: 06/07/2023]
Abstract
Nile crocodiles (Crocodylus niloticus) are important apex predators in many tropical and subtropical aquatic habitats throughout much of sub-Saharan Africa. In South Africa, large crocodile populations inhabit lakes and wetlands that are impacted by organochlorine pesticides (OCPs). Despite the continued use of these compounds and their potential adverse effects on key wildlife populations in southern Africa, limited ecotoxicoloigcal data exist. In this study, we examined the accumulation of OCPs in fat tissues of live, wild Nile crocodiles from iSimangaliso Wetland Park, a region of significant biological importance. All samples (n = 15) contained multiple contaminants in highly elevated concentrations, with total residue burdens varying between 3600 and 8000 ng g-1 ww. DDT and its metabolites were the dominant compounds detected in most samples, with ∑DDT concentrations ranging between 520 and 3100 ng g-1 ww. Elevated levels of other OCPs were also detected, including lindane (67-410 ng g-1 ww), aldrin (150-620 ng g-1 ww) and heptachlor (170-860 ng g-1 ww). Our findings show that crocodiles are exposed to OCPs throughout their range within iSimangaliso Wetland Park and contain some of the highest concentrations ever recorded in crocodilian tissue. Results indicate the need for a greater understanding of the impacts of OCP exposure and toxicological responses in crocodiles from iSimangaliso, and in Nile crocodile populations in general. The novel surgical technique described in this study provides an effective method for assessing relationships between contaminant body burdens and their potential reproductive and developmental consequences in crocodilians.
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Affiliation(s)
- Archibold Buah-Kwofie
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa
| | - Marc S Humphries
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa.
| | - Xander Combrink
- Nature Conservation Department, Tshwane University of Technology, South Africa
| | - Jan G Myburgh
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, South Africa
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9
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Organochlorine Pesticide Residues in Caudal Scutes of Belize Morelet's Crocodiles (Crocodylus moreletii). J HERPETOL 2016. [DOI: 10.1670/14-029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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Arukwe A, Myburgh J, Langberg HA, Adeogun AO, Braa IG, Moeder M, Schlenk D, Crago JP, Regoli F, Botha C. Developmental alterations and endocrine-disruptive responses in farmed Nile crocodiles (Crocodylus niloticus) exposed to contaminants from the Crocodile River, South Africa. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 173:83-93. [PMID: 26851571 DOI: 10.1016/j.aquatox.2015.12.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 12/26/2015] [Accepted: 12/31/2015] [Indexed: 06/05/2023]
Abstract
In the present study, the developmental (including fertility) and endocrine-disruptive effects in relation to chemical burden in male and female Nile crocodiles (Crocodylus niloticus), from a commercial crocodile farm in the Brits district, South Africa, exposed to various anthropogenic aquatic contaminants from the natural environment was investigated. Hepatic transcript levels for vitellogenin (Vtg), zona pellucida (ZP) and ERα (also in gonads) were analyzed using real-time PCR. Plasma estradiol-17β (E2), testosterone (T) and 11-ketotestosterone (11-KT) were analyzed using enzyme immunoassay. Gonadal aromatase and hepatic testosterone metabolism (6β-hydroxylase (6β-OHase)) were analyzed using biochemical methods. Overall, there is high and abnormal number (%) of infertile and banded eggs during the studied reproductive seasons, showing up to 57 and 34% of infertile eggs in the 2009/2010 and 2013/2014 seasons, respectively. In addition, the percentage of banded eggs ranged between 10 and 19% during the period of 2009-2014 seasons. While hepatic ERα, Vtg, ZP mRNA and testosterone 6β-OHase, were equally expressed in female and male crocodiles, gonadal ERα mRNA and aromatase activity were significantly higher in females compared to male crocodiles. On the other hand, plasma T and 11-KT levels were significantly higher in males, compared to female crocodiles. Principal component analysis (PCA) produced significant grouping that revealed correlative relationships between reproductive/endocrine-disruptive variables and liver contaminant burden, that further relates to measured contaminants in the natural environment. The overall results suggest that these captive pre-slaughter farm crocodiles exhibited responses to anthropogenic aquatic contaminants with potentially relevant consequences on key reproductive and endocrine pathways and these responses may be established as relevant species endocrine disruptor biomarkers of exposure and effects in this threatened species.
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Affiliation(s)
- Augustine Arukwe
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
| | - Jan Myburgh
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Håkon A Langberg
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Aina O Adeogun
- Department of Zoology, University of Ibadan, Ibadan, Nigeria
| | - Idunn Godal Braa
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
| | - Monika Moeder
- Helmholtz center for Environmental Research UFZ, Department of Analytical Chemistry, Leipzig, Germany
| | - Daniel Schlenk
- Department of Environmental Sciences, University of California, Riverside, CA 92521, United States
| | - Jordan Paul Crago
- Department of Environmental Sciences, University of California, Riverside, CA 92521, United States
| | - Francesco Regoli
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Ancona, Italy
| | - Christo Botha
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
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11
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Lázaro WL, de Oliveira RF, dos Santos-Filho M, da Silva CJ, Malm O, Ignácio ÁRA, Díez S. Non-lethal sampling for mercury evaluation in crocodilians. CHEMOSPHERE 2015; 138:25-32. [PMID: 26026900 DOI: 10.1016/j.chemosphere.2015.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 04/20/2015] [Accepted: 05/03/2015] [Indexed: 06/04/2023]
Abstract
Mercury (Hg) is a ubiquitous environmental contaminant that poses potential threats to ecosystems due to its toxicity to humans and wildlife. The development of non-lethal sampling techniques is a critical step for evaluation of Hg in threatened species in tropical floodplain environments, where most of Hg found is the result of land use and gold mining activities, and more methylation sites are available. We evaluated the spatial and seasonal effectiveness of caudal scutes and claws to estimate Hg bioaccumulation in crocodilians (Caiman yacare), in the scarcely documented Pantanal. Hence, we investigated the potential for Hg bioaccumulation in top predators according to its proximity to mining sites, and in water bodies with different hydrological characteristics and connectivity with the main river during two phases of the flood pulse (dry and flood). The highest Hg concentrations were detected in caimans captured close to mining activities, in claws (2176 ng g(-1) ww) and caudal scutes (388 ng g(-1) ww). THg concentration in claws was related to the flood season and its mean concentration was thirteen fold higher than Hg concentration in scutes during whole year. Both tissues were found to be effective as non-lethal sampling techniques for measuring Hg bioaccumulation in reptiles over time. Nevertheless, claw tissue seems to have a more consistent result, since its constitutional chemical characteristics makes it a better indicator of spatial patterns that influence on Hg exposure.
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Affiliation(s)
- Wilkinson L Lázaro
- Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil
| | | | | | | | - Olaf Malm
- Federal University of Rio de Janeiro, Carlos Chagas Filho Biophysics Institute, Eduardo Penna Franca Radioisotopes Laboratory, Rio de Janeiro, Brazil
| | - Áurea R A Ignácio
- Mato Grosso State University, UNEMAT, Biology Department, Cáceres, Brazil
| | - Sergi Díez
- Environmental Chemistry Department, Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Barcelona, Spain.
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12
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Wu T, Hong B, Wu X, Wu J, Wang X, Yi Z, Zhao J, Zhan M, Mai B. Persistent halogenated compounds in captive Chinese alligators (Alligator sinensis) from China. CHEMOSPHERE 2014; 110:23-30. [PMID: 24880595 DOI: 10.1016/j.chemosphere.2014.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 02/18/2014] [Accepted: 03/05/2014] [Indexed: 06/03/2023]
Abstract
While a number of studies have reported residual levels of persistent halogenated compounds (PHCs) in crocodilia, there is still a dearth of information on the Chinese alligator, a critically endangered crocodilian species. In the present study, several PHCs, including polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethane and its metabolites (DDTs), were detected in the adult tissues, neonates, and eggs of captive Chinese alligators from China. The concentrations of ΣPBDEs, ΣPCBs, and ΣDDTs in Chinese alligators ranged from 0.11 to 16.1, 1.12 to 22.2, and 6.03 to 1020ngg(-1) wet weight, respectively, with higher levels of ΣPCBs and ΣDDTs in the neonates and eggs than in muscle tissues. The ΣDDT residues in the studied Chinese alligators were at the high end of reported ranges from crocodilia around the world, and some results exceeded levels known to cause a female-biased sex ratio in crocodilians.
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Affiliation(s)
- Ting Wu
- College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241003, China
| | - Bing Hong
- College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241003, China
| | - Xiaobing Wu
- College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241003, China.
| | - Jiangping Wu
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
| | - Xinming Wang
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zhigang Yi
- College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Juan Zhao
- College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241003, China
| | - Miao Zhan
- College of Environmental Science and Engineering, Anhui Normal University, Wuhu 241003, China
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
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13
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Faust DR, Hooper MJ, Cobb GP, Barnes M, Shaver D, Ertolacci S, Smith PN. Inorganic elements in green sea turtles (Chelonia mydas): relationships among external and internal tissues. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:2020-2027. [PMID: 24889685 DOI: 10.1002/etc.2650] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/11/2014] [Accepted: 05/26/2014] [Indexed: 06/03/2023]
Abstract
Inorganic elements from anthropogenic sources have entered marine environments worldwide and are detectable in marine organisms, including sea turtles. Threatened and endangered classifications of sea turtles have heretofore made assessments of contaminant concentrations difficult because of regulatory restrictions on obtaining samples using nonlethal techniques. In the present study, claw and skin biopsy samples were examined as potential indicators of internal tissue burdens in green sea turtles (Chelonia mydas). Significant relationships were observed between claw and liver, and claw and muscle concentrations of mercury, nickel, arsenic, and selenium (p < 0.05). Similarly, significant relationships were observed between skin biopsy concentrations and those in liver, kidney, and muscle tissues for mercury, arsenic, selenium, and vanadium (p < 0.05). Concentrations of arsenic, barium, chromium, nickel, strontium, vanadium, and zinc in claws and skin biopsies were substantially elevated when compared with all other tissues, indicating that these highly keratinized tissues may represent sequestration or excretion pathways. Correlations between standard carapace length and cobalt, lead, and manganese concentrations were observed (p < 0.05), indicating that tissue concentrations of these elements may be related to age and size. Results suggest that claws may indeed be useful indicators of mercury and nickel concentrations in liver and muscle tissues, whereas skin biopsy inorganic element concentrations may be better suited as indicators of mercury, selenium, and vanadium concentrations in liver, kidney, and muscle tissues of green sea turtles.
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Affiliation(s)
- Derek R Faust
- The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, Texas, USA
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14
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Charruau P, Niño-Torres CA. A third case of amelia in Morelet's crocodile from the Yucatan Peninsula. DISEASES OF AQUATIC ORGANISMS 2014; 109:263-267. [PMID: 24991853 DOI: 10.3354/dao02743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Congenital defects in crocodilians have received little interest. In the context of global change and increasing threats to biodiversity, data on birth defects occurring in wildlife could be of importance for estimating the health of species populations and their ecosystems. Herein, we report the first case of amelia (i.e. absence of limbs) in Morelet's crocodiles Crocodylus moreletii from Mexico and the third on the southern Yucatan Peninsula. The crocodile in question was a juvenile (41 cm total length) captured in July 2012 in the Río Hondo, the river that forms the border between Mexico and Belize south of the state of Quintana Roo. The prevalence of this malformation in the C. moreletii population of Río Hondo (0.35%) is similar to that reported in 2 previous cases in Belize. Several causes of birth defects in crocodilians have previously been cited in the literature. Although we do not have relevant information to elucidate this case, we discuss some plausible explanations for this birth defect.
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Affiliation(s)
- Pierre Charruau
- Centro del Cambio Global y la Sustentabilidad en el Sureste, A.C., C.P. 86080, Villahermosa, Tabasco, Mexico
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15
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Bouwman H, Booyens P, Govender D, Pienaar D, Polder A. Chlorinated, brominated, and fluorinated organic pollutants in Nile crocodile eggs from the Kruger National Park, South Africa. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2014; 104:393-402. [PMID: 24703242 DOI: 10.1016/j.ecoenv.2013.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 12/02/2013] [Accepted: 12/10/2013] [Indexed: 05/02/2023]
Abstract
Repeated annual episodes of Nile crocodile deaths in two isolated areas of the Kruger National Park prompted the investigation of possible organohalogen pollutant involvement. Crocodile eggs were collected close to one of the mortality sites (Gorge) as well as from a crocodile farm (CF) as reference. ∑DDT was significantly higher in Gorge (450ng/g wm) than in CF eggs (85ng/g wet mass). Percentage DDT of ∑DDT was significantly higher in CF (14 per cent) than in Gorge eggs (5 per cent). Mean ∑DDT was almost 70 times higher than mean ∑PCB in Gorge eggs. HCB, β-HCH, mirex, brominated flame retardants (BFRs), and perfluorinated compounds (PFCs) occurred at lower concentrations. We believe that the BFR and PFCs data represent the first published results for any crocodile egg. Thickening of the outer eggshell layer of Gorge eggs was significantly associated with higher concentrations of ∑DDT. Concentrations of ∑DDT and other pollutants were in the same range as eggs from elsewhere, where there were no mortalities. Concentrations of ∑DDT in eggs from healthy Australian crocodiles were of the same orders of magnitude as the current study, making it highly unlikely that the concentrations of pollutants measured in the present study would have caused or substantially contributed towards the mortalities observed. Concerns about reproduction and behaviour remain. As large predators, crocodilians are at the apex of the freshwater aquatic food web. More research is needed to guide measures to manage African freshwater systems so that it will also sustainably accommodate these large, long-lived animals.
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Affiliation(s)
- Hindrik Bouwman
- Research Unit: Environmental Sciences and Development, North-West University, Potchefstroom, South Africa.
| | - Paul Booyens
- Research Unit: Environmental Sciences and Development, North-West University, Potchefstroom, South Africa
| | - Danny Govender
- Scientific Services, SANParks, Skukuza, South Africa; Department of Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, South Africa
| | - Danie Pienaar
- Scientific Services, SANParks, Skukuza, South Africa
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Charruau P, Hénaut Y, Álvarez-Legorreta T. Organochlorine pesticides in nest substratum and infertile eggs of American crocodiles (Reptilia, Crocodylidae) in a Mexican Caribbean atoll. CARIBB J SCI 2013. [DOI: 10.18475/cjos.v47i1.a2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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St John JA, Braun EL, Isberg SR, Miles LG, Chong AY, Gongora J, Dalzell P, Moran C, Bed'hom B, Abzhanov A, Burgess SC, Cooksey AM, Castoe TA, Crawford NG, Densmore LD, Drew JC, Edwards SV, Faircloth BC, Fujita MK, Greenwold MJ, Hoffmann FG, Howard JM, Iguchi T, Janes DE, Khan SY, Kohno S, de Koning AJ, Lance SL, McCarthy FM, McCormack JE, Merchant ME, Peterson DG, Pollock DD, Pourmand N, Raney BJ, Roessler KA, Sanford JR, Sawyer RH, Schmidt CJ, Triplett EW, Tuberville TD, Venegas-Anaya M, Howard JT, Jarvis ED, Guillette LJ, Glenn TC, Green RE, Ray DA. Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes. Genome Biol 2012; 13:415. [PMID: 22293439 PMCID: PMC3334581 DOI: 10.1186/gb-2012-13-1-415] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described.
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Stoker C, Repetti MR, García SR, Zayas MA, Galoppo GH, Beldoménico HR, Luque EH, Muñoz-de-Toro M. Organochlorine compound residues in the eggs of broad-snouted caimans (Caiman latirostris) and correlation with measures of reproductive performance. CHEMOSPHERE 2011; 84:311-317. [PMID: 21531435 DOI: 10.1016/j.chemosphere.2011.04.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 02/15/2011] [Accepted: 04/01/2011] [Indexed: 05/30/2023]
Abstract
Organochlorine compounds (OCCs), like pesticides (OCPs) and polychlorinated biphenyls (PCBs), are persistent lipophilic chemicals classified as endocrine-disruptors. Caiman latirostris inhabits wetlands throughout north-eastern Argentina and may accumulate OCCs. The aims of this study were to determine OCC residues in the eggs of C. latirostris and to correlate OCC burden with clutch size, hatching success and hatchling survival as measures of reproductive performance. Fourteen caiman clutches were harvested from sites with different degrees of anthropogenic intervention on wetlands surrounding Paraná River tributaries. Two to four eggs by clutch were used to quantify OCCs. OCP residues were found in all clutches. The principal contributors to the OCPs burden were the DDT family (range BDL-153.0 ng g(-1) lipid) and oxychlordane (range BDL-34.3 ng g(-1) lipid). PCBs were present in 92.9% of the clutches (range BDL-136.6 ng g(-1) lipid). Both higher concentrations and higher diversity of pesticides, including endosulfan sulfate, were found in the nests harvested close to croplands. A negative correlation was found between clutch size and ∑OCCs (p=0.02, Pearson r=-0.53, r(2)=0.28), mainly due to the ∑OCPs (p=0.04, Pearson r=-0.54, r(2)=0.30). Since egg OCCs concentrations predict maternal burden, present findings suggest that higher OCCs exposure could lead to smaller clutches. Although, other factors like mother age could influence clutch size. Additionally, as caimans are a long-lived and non-migratory species, the maternal OCCs burden reflects the environmental status throughout their home range; thus, caiman eggs could be useful as a biomonitor of local contamination.
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Affiliation(s)
- C Stoker
- Laboratory of Endocrinology and Hormone-dependent Tumors, School of Biochemistry and Biological Sciences, Universidad Nacional del Litoral, Santa Fe, Argentina
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McVay JD, Rodriguez D, Rainwater TR, Dever JA, Platt SG, McMurry ST, Forstner MRJ, Densmore LD. Evidence of multiple paternity in Morelet's Crocodile (Crocodylus moreletii) in Belize, CA, inferred from microsatellite markers. ACTA ACUST UNITED AC 2009; 309:643-8. [PMID: 18831002 DOI: 10.1002/jez.500] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Microsatellite data were generated from hatchlings collected from ten nests of Morelet's Crocodile (Crocodylus moreletii) from New River Lagoon and Gold Button Lagoon in Belize to test for evidence of multiple paternity. Nine microsatellite loci were genotyped for 188 individuals from the 10 nests, alongside 42 nonhatchlings from Gold Button Lagoon. Then mitochondrial control region sequences were generated for the nonhatchlings and for one individual from each nest to test for presence of C. acutus-like haplotypes. Analyses of five of the nine microsatellite loci revealed evidence that progeny from five of the ten nests were sired by at least two males. These data suggest the presence of multiple paternity as a mating strategy in the true crocodiles. This information may be useful in the application of conservation and management techniques to the 12 species in this genus, most of which are threatened or endangered.
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Affiliation(s)
- John D McVay
- Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
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20
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Rainwater TR, Selcer KW, Nespoli LM, Finger AG, Ray DA, Platt SG, Smith PN, Densmore LD, Anderson TA, McMurry ST. Plasma vitellogenin in Morelet's crocodiles from contaminated habitats in northern Belize. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2008; 153:101-9. [PMID: 17826876 DOI: 10.1016/j.envpol.2007.07.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 07/20/2007] [Accepted: 07/25/2007] [Indexed: 05/17/2023]
Abstract
Vitellogenin induction has been widely used as a biomarker of endocrine disruption in wildlife, but few studies have investigated its use in wild reptiles living in contaminated habitats. This study examined vitellogenin induction in Morelet's crocodiles (Crocodylus moreletii) from wetlands in northern Belize contaminated with organochlorine (OC) pesticides. Vitellogenin was measured in 381 crocodile plasma samples using a vitellogenin ELISA previously developed for this species. Vitellogenin was detected in nine samples, all from adult females sampled during the breeding season. Males and juvenile females did not contain detectable levels of vitellogenin; however, many of these animals contained OC pesticides in their caudal scutes, confirming contaminant exposure. The lack of a vitellogenic response in these animals may be attributable to several factors related to the timing and magnitude of exposure to endocrine-disrupting chemicals and should not be interpreted as an absence of other contaminant-induced biological responses.
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Affiliation(s)
- Thomas R Rainwater
- The Institute of Environmental and Human Health and Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409-1163, USA.
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Smith PN, Cobb GP, Godard-Codding C, Hoff D, McMurry ST, Rainwater TR, Reynolds KD. Contaminant exposure in terrestrial vertebrates. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2007; 150:41-64. [PMID: 17706848 DOI: 10.1016/j.envpol.2007.06.009] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 06/01/2007] [Indexed: 05/16/2023]
Abstract
Here we review mechanisms and factors influencing contaminant exposure among terrestrial vertebrate wildlife. There exists a complex mixture of biotic and abiotic factors that dictate potential for contaminant exposure among terrestrial and semi-terrestrial vertebrates. Chemical fate and transport in the environment determine contaminant bioaccessibility. Species-specific natural history characteristics and behavioral traits then play significant roles in the likelihood that exposure pathways, from source to receptor, are complete. Detailed knowledge of natural history traits of receptors considered in conjunction with the knowledge of contaminant behavior and distribution on a site are critical when assessing and quantifying exposure. We review limitations in our understanding of elements of exposure and the unique aspects of exposure associated with terrestrial and semi-terrestrial taxa. We provide insight on taxa-specific traits that contribute, or limit exposure to, transport phenomenon that influence exposure throughout terrestrial systems, novel contaminants, bioavailability, exposure data analysis, and uncertainty associated with exposure in wildlife risk assessments. Lastly, we identify areas related to exposure among terrestrial and semi-terrestrial organisms that warrant additional research.
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Affiliation(s)
- Philip N Smith
- The Institute of Environmental & Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX, USA.
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Rainwater TR, Wu TH, Finger AG, Cañas JE, Yu L, Reynolds KD, Coimbatore G, Barr B, Platt SG, Cobb GP, Anderson TA, McMurry ST. Metals and organochlorine pesticides in caudal scutes of crocodiles from Belize and Costa Rica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2007; 373:146-56. [PMID: 17182086 DOI: 10.1016/j.scitotenv.2006.11.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 11/06/2006] [Accepted: 11/08/2006] [Indexed: 05/13/2023]
Abstract
Despite high animal diversity in the Neotropics and the largely unregulated use and disposal of pesticides and industrial chemicals in Central America, few data exist regarding accumulation of environmental contaminants in Central American wildlife. In this study we examined accumulation of metals and organochlorine (OC) pesticides in caudal scutes of crocodiles from Belize and Costa Rica. Scutes from Morelet's crocodiles (Crocodylus moreletii) from two sites in northern Belize were analyzed for metals, and scutes from American crocodiles (C. acutus) from one site in Costa Rica were analyzed for metals and OC pesticides. All scutes (n=25; one scute from each of 25 individuals) contained multiple contaminants. Mercury was the predominant metal detected, occurring in all scutes examined from both species. Other metals detected include cadmium, copper, lead, and zinc. American crocodile scutes from Costa Rica contained multiple OC pesticides, including endrin, methoxychlor, p,p'-DDE, and p,p'-DDT, all of which occurred in 100% of scutes analyzed (n=6). Mean metal and OC concentrations varied in relation to those previously reported in crocodilian scutes from other localities in North, Central, and South America. OC concentrations in American crocodile scutes were generally higher than those previously reported for other Costa Rican wildlife. Currently, caudal scutes may serve as general, non-lethal indicators of contaminant accumulation in crocodilians and their areas of occurrence. However, a better understanding of the relationships between pollutant concentrations in scutes, internal tissues, and environmental matrices at sample collection sites are needed to improve the utility of scutes in future ecotoxicological investigations.
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Affiliation(s)
- Thomas R Rainwater
- The Institute of Environmental and Human Health, Department of Environmental Toxicology, Texas Tech University, Lubbock, TX 79409, USA.
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