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Zenkov AV, Sushko ES, Mogilnaya OA, Volochaev MN, Shabanov AV, Kamnev AA, Tugarova AV, Kudryasheva NS. Application of the luminous bacterium Photobacterium phosphoreum for toxicity monitoring of selenite and its reduction to selenium(0) nanoparticles. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 325:125078. [PMID: 39250849 DOI: 10.1016/j.saa.2024.125078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 08/09/2024] [Accepted: 08/29/2024] [Indexed: 09/11/2024]
Abstract
Luminous marine bacteria are traditionally used as a bioassay due to the convenience and high rate of registering the intensity of their physiological function - luminescence. This study aimed to develop the application of Photobacterium phosphoreum in traditional and novel fields - toxicity monitoring and biotechnology. We demonstrated (1) effects of selenite ions on bioluminescence, and (2) biotransformation of selenite to selenium(0) in the form of nanoparticles. The effects of selenite (SeO32-) on the intensity of bacterial bioluminescence were studied, and its dependencies on exposure time and concentration of Na2SeO3 were analyzed. Bioluminescence activation and inhibition were revealed; dose-effect dependencies corresponded to the hormesis model. The toxicity of SeO32- was characterized by an effective concentration of 10-3 M. Effects of SeO32- on reactive oxygen species (ROS) in bacterial suspensions were studied. High positive correlations were found between the bioluminescence intensity and ROS content, which indicates the decisive role of ROS and associated redox processes in the bioeffects of selenite ions. Scanning and transmission electron microscopy revealed the presence of nano-structures in the bacteria exposed to selenite. The energy dispersion spectrum detected a high content of selenium in the nanoparticles. The particle size distribution depended on Na2SeO3 concentration; maxima of the distribution varied within 45-55 nm.
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Affiliation(s)
- Andrei V Zenkov
- School of Fundamental Biology and Biotechnology, Siberian Federal University, 660041 Krasnoyarsk, Russia
| | - Ekaterina S Sushko
- School of Fundamental Biology and Biotechnology, Siberian Federal University, 660041 Krasnoyarsk, Russia; Institute of Biophysics SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 660036 Krasnoyarsk, Russia; Institute of Physics SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 660036 Krasnoyarsk, Russia.
| | - Olga A Mogilnaya
- Institute of Biophysics SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 660036 Krasnoyarsk, Russia
| | - Mikhail N Volochaev
- Institute of Physics SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 660036 Krasnoyarsk, Russia
| | - Alexandr V Shabanov
- Institute of Physics SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 660036 Krasnoyarsk, Russia
| | - Alexander A Kamnev
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Federal Scientific Center of the Russian Academy of Sciences, 410049 Saratov, Russia
| | - Anna V Tugarova
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Federal Scientific Center of the Russian Academy of Sciences, 410049 Saratov, Russia
| | - Nadezhda S Kudryasheva
- School of Fundamental Biology and Biotechnology, Siberian Federal University, 660041 Krasnoyarsk, Russia; Institute of Biophysics SB RAS, Federal Research Center "Krasnoyarsk Science Center SB RAS", 660036 Krasnoyarsk, Russia.
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Gerson JR, Dorman R, Eagles-Smith C, Bernhardt ES, Walters D. Lethal impacts of selenium counterbalance the potential reduction in mercury bioaccumulation for freshwater organisms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 287:117293. [PMID: 34030024 DOI: 10.1016/j.envpol.2021.117293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
Mercury (Hg), a potent neurotoxic element, can biomagnify through food webs once converted into methylmercury (MeHg). Some studies have found that selenium (Se) exposure may reduce MeHg bioaccumulation and toxicity, though this pattern is not universal. Se itself can also be toxic at elevated levels. We experimentally manipulated the relative concentrations of dietary MeHg and Se (as selenomethionine [SeMet]) for an aquatic grazer (the mayfly, Neocloeon triangulifer) and its food source (diatoms). Under low MeHg treatment (0.2 ng/L), diatoms exhibited a quadratic pattern, with decreasing diatom MeHg concentration up to 2.0 μg Se/L and increasing MeHg accumulation at higher SeMet concentrations. Under high MeHg treatment (2 ng/L), SeMet concentrations had no effect on diatom MeHg concentrations. Mayfly MeHg concentrations and biomagnification factors (concentration of MeHg in mayflies: concentration of MeHg in diatoms) declined with SeMet addition only in the high MeHg treatment. Mayfly MeHg biomagnification factors decreased from 5.3 to 3.3 in the high MeHg treatment, while the biomagnification factor was constant with an average of 4.9 in the low MeHg treatment. The benefit of reduced MeHg biomagnification was offset by non-lethal effects and high mortality associated with 'protective' levels of SeMet exposure. Mayfly larvae escape behavior (i.e., startle response) was greatly reduced at early exposure days. Larvae took nearly twice as long to metamorphose to adults at high Se concentrations. The minimum number of days to mayfly emergence did not differ by SeMet exposure, with an average of 13 days. We measured an LC50SeMet for mayflies of 3.9 μg Se/L, with complete mortality at concentrations ≥6.0 μg Se/L. High reproductive mortality occurred at elevated SeMet exposures, with only 0-18% emergence at ≥4.12 μg Se/L. Collectively, our results suggest that while there is some evidence that Se can reduce MeHg accumulation at the base of the food web at specific exposure levels of SeMet and MeHg, Se is also toxic to mayflies and could lead to negative effects that extend across ecosystem boundaries.
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Affiliation(s)
| | - Rebecca Dorman
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA
| | - Collin Eagles-Smith
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Corvallis, OR, 97330, USA
| | | | - David Walters
- U.S. Geological Survey, Columbia Environmental Research Center, Columbia, MO, 65201, USA
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Brooks ML, Lovvorn JR, Behnke JH, Anderson EM. Detecting silent stressors: Trace element effects on nutritional status of declining scoter ducks of Puget Sound, USA. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 766:144247. [PMID: 33421779 DOI: 10.1016/j.scitotenv.2020.144247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/10/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
White-winged scoters (Melanitta fusca; WWSC) and surf scoters (M. perspicillata; SUSC) have declined by over 60% in recent decades. Identifying contributing factors from within a mosaic of sublethal, multiple stressors is challenging. In urbanized Puget Sound, Washington, USA where scoters winter, changes in prey availability explained only a portion of local declines, suggesting that other "silent stressors" such as sublethal contaminants might play a role. Past studies of pollutant effects on scoters used Fisherian statistics that often revealed few correlates; however, novel statistical approaches could detect and provide more insights about sublethal impacts. Our objectives were to (1) relate pollutant accumulation to health of the birds, and (2) compare permutational multivariate statistics with traditional approaches in identifying sublethal health effects. We collected scoters from three locations in Puget Sound in December 2005 and March 2006, and measured cadmium (Cd), mercury (Hg), and selenium (Se) levels in livers and kidneys. To assess impacts of low contaminants levels in tissues on nutritional status (whole-body mass, lipid, and protein; and triglycerides, β-hydroxybutyrate, and uric acid in blood), we compared statistical methods. Permutational multivariate methods use Monte Carlo techniques to assess how an integrated matrix of physiological responses in each animal respond to contaminants. Univariate regressions revealed very few and inconsistent relationships. In contrast, multivariate models showed that liver Hg and Se explained 25% of the variance in nutritional status of white-winged scoters; and in surf scoters, Cd, Hg, and Se in tissues explained 14 to 27% of nutritional status depending on site. The influence of these factors equals other aspects of habitat such as foraging conditions. Our study indicates that permutational multivariate statistics can be a powerful tool for identifying sublethal contaminant associations that, with non-contaminant stressors, can influence nutritional status and thus, contribute to population dynamics.
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Affiliation(s)
- Marjorie L Brooks
- Zoology Program, School of Biological Sciences, Southern Illinois University, 1125 Lincoln Dr., MC 6501, Carbondale, IL 62901, USA.
| | - James R Lovvorn
- Zoology Program, School of Biological Sciences, Southern Illinois University, 1125 Lincoln Dr., MC 6501, Carbondale, IL 62901, USA.
| | - Jessica Hallman Behnke
- Zoology Program, School of Biological Sciences, Southern Illinois University, 1125 Lincoln Dr., MC 6501, Carbondale, IL 62901, USA.
| | - Eric M Anderson
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA.
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Calabrese EJ, Agathokleous E. Theodosius Dobzhansky's view on biology and evolution v.2.0: "Nothing in biology makes sense except in light of evolution and evolution's dependence on hormesis-mediated acquired resilience that optimizes biological performance and numerous diverse short and longer term protective strategies". ENVIRONMENTAL RESEARCH 2020; 186:109559. [PMID: 32344211 DOI: 10.1016/j.envres.2020.109559] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/15/2020] [Accepted: 04/19/2020] [Indexed: 05/17/2023]
Abstract
The hormetic, biphasic dose response, is highly generalizable, being independent of biological model, level of biological organization, endpoint, inducing agent, and mechanisms. It plays a significant role in mediating both constitutive and adaptable responses in essentially all cells and organisms. The present paper provides both a historical overview of the origin of the hormetic concept in the biological and biomedical sciences, and its potential role in ecology, evolution, and development. These integrative findings provide a broad scientific framework to better understand complex evolutionary-based selection strategies, affecting survival, lifespan, fecundity, learning/memory, tissue repair, reproduction and cooperation, and developmental processes, and offering resilience in the presence of numerous challenges.
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Affiliation(s)
- Edward J Calabrese
- Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA 01003, USA.
| | - Evgenios Agathokleous
- Institute of Ecology, Key Laboratory of Agrometeorology of Jiangsu Province, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing Jiangsu, China.
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Sun H, Zheng M, Song J, Huang S, Pan Y, Gong R, Lin Z. Multiple-species hormetic phenomena induced by indole: A case study on the toxicity of indole to bacteria, algae and human cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 657:46-55. [PMID: 30530218 DOI: 10.1016/j.scitotenv.2018.12.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 11/30/2018] [Accepted: 12/02/2018] [Indexed: 06/09/2023]
Abstract
Hormesis is a dose-response relationship phenomenon characterized by low-dose stimulation and high-dose inhibition. Although hormetic phenomena have been reported in broadly ranging biological areas, there is still no unified mechanism of hormesis. Investigating multiple-species hormesis of one compound and then exploring the possible mechanism may be an effective approach to clarify the reason for the occurrence of hormetic phenomena in a broad range of organisms. In this study, indole was selected as the test chemical due to the broad biological and hormetic effects of indole compounds. The results show that indole induces multiple-species hormetic phenomena in bacteria (Aliivibrio fischeri (A. fischeri), Escherichia coli and Bacillus subtilis), algae (Microcystis aeruginosa and Selenastrum capricornutum), and human cells (human skin fibroblasts and human cervical cancer cells). Through in-depth investigation of the time-dependent hormetic effects of indole, indole derivatives and indole's structural analogs on the bioluminescence of A. fischeri, indole ring has been identified as the potential key structure that causes indole to act on quorum sensing of A. fischeri to induce hormetic effects on the bioluminescence at lag, logarithmic, and stationary phases. Therefore, the occurrence of multiple-species hormetic phenomena is speculated to be derived from the action of indole on the cell-to-cell communication of organism cells. This paper can not only further confirm the generalizability of hormesis but also provide a reasonable explanation for hormesis, which will benefit the development of hormesis and the risk assessment of environmental pollutants.
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Affiliation(s)
- Haoyu Sun
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Min Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Jinyuan Song
- China Solid Waste and Chemical Management Technology Center, Ministry of Environmental Protection, Beijing 100029, China
| | - Shengyou Huang
- Shanghai International Studies University Bilingual School, Shanghai 200092, China
| | - Yongzheng Pan
- College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China
| | - Ruochong Gong
- Shanghai Foreign Language Primary School Affiliated to Shanghai International Studies University, Shanghai 200092, China
| | - Zhifen Lin
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China; Shanghai Key Lab of Chemical Assessment and Sustainability, Shanghai, China; State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, China.
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6
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Wolfe JD, Lane OP, Brigham RM, Hall BD. Mercury exposure to red-winged blackbirds (Agelaius phoeniceus) and dragonfly (Odonata: Aeshnidae) nymphs in Prairie Pothole wetlands. Facets (Ott) 2018. [DOI: 10.1139/facets-2017-0086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Prairie Pothole Region (PPR) in the northern Great Plains is an area of ecological significance, serving as an important breeding site for avian wildlife. However, organisms feeding within the PPR may be at risk of mercury (Hg) exposure due to deposition of anthropogenic emissions and the high Hg methylation potential of PPR wetlands. We quantified Hg concentrations in red-winged blackbirds’ ( Agelaius phoeniceus (Linnaeus, 1766); RWBLs) blood, feathers, and eggs in the spring and summer breeding season and compared our values with those from RWBLs sampled from ecoregions across North America. Hg concentrations in whole water, aeshnid dragonfly nymphs, and RWBL tissues varied by wetland and were below those considered to elicit acute effects in wildlife, and egg total Hg (THg) concentrations were significantly related to spring whole water methylmercury concentrations. Only RWBL blood THg concentrations showed a clear increase in summer compared with spring, resulting in decoupling of summer blood and feather THg concentrations. Moreover, blood THg concentrations varied by ecoregion, with those impacted by an industrial point source exhibiting high Hg levels. Our study emphasizes that tissue renewal time as well as ecological factors such as competition and diet shifts are important considerations when using RWBLs to assess biological Hg exposure.
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Affiliation(s)
- Jared D. Wolfe
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Oksana P. Lane
- Biodiversity Research Institute, 276 Canco Road, Portland, ME 04103, USA
| | - R. Mark Brigham
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Britt D. Hall
- Department of Biology, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
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7
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Finger JW, Hamilton MT, Glenn TC, Tuberville TD. Dietary Selenomethionine Administration in the American Alligator (Alligator mississippiensis): Hepatic and Renal Se Accumulation and Its Effects on Growth and Body Condition. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 72:439-448. [PMID: 28150020 DOI: 10.1007/s00244-017-0370-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/17/2017] [Indexed: 06/06/2023]
Abstract
Selenium (Se) is an essential trace nutrient, but in excess, it can induce toxicity. Incomplete combustion of coal produces coal combustion wastes, which are enriched in Se and often disposed of in aquatic basins. While a multitude of studies have investigated Se accumulation in vertebrates, few studies have examined its effects on longer-lived top trophic carnivores, such as the American alligator (Alligator mississippiensis). In this study, alligators were fed one of three Dietary Treatments: mice injected with water (controls) or water supplemented with 1000 or 2000 ppm selenomethionine (SeMet). Dietary Treatment significantly affected Se levels in both the liver (p < 0.0001; raw mean ± SE: 1000 ppm group, 35.20 ± 6.32 ppm; 2000 ppm group, 49.97 ± 4.00 ppm) and kidney (p < 0.0001; raw mean ± SE: 1000 ppm group, 101.60 ± 8.64 ppm; 2000 ppm, 96.38 ± 5.81 ppm), which were significantly higher in alligators fed SeMet than in controls. Post-treatment head length, used to control for size variation, was negatively related to both kidney (p = 0.0142) and liver (p = 0.0010) Se concentrations. Dietary treatment with SeMet significantly reduced body condition (1000 ppm, p < 0.0029; 2000 ppm, p = 0.0075), but it significantly increased growth (1000 ppm, p < 0.0001; 2000 ppm, p = 0.0316). Body condition and growth remained unchanged in control alligators (p > 0.05). Our results demonstrate alligators are capable of accumulating high levels of Se through trophic transfer. The positive effects of accumulation on growth may demonstrate Se essentiality, whereas the negative effects on condition may demonstrate toxicity. Accumulation also was associated with mortality, further demonstrating toxicity. Future studies should further investigate the physiological effects of Se accumulation in long-lived, top-trophic carnivores.
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Affiliation(s)
- John W Finger
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA.
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA.
- Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, 30602, USA.
- Department of Biological Sciences, Auburn University, Auburn, AL, 36849, USA.
| | - Matthew T Hamilton
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA
| | - Travis C Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, 30602, USA
- Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, 30602, USA
| | - Tracey D Tuberville
- Savannah River Ecology Laboratory, University of Georgia, PO Drawer E, Aiken, SC, 29802, USA
- Interdisciplinary Toxicology Program, University of Georgia, Athens, GA, 30602, USA
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Mayo M, Collier ZA, Winton C, Chappell MA. Data-Driven Method to Estimate Nonlinear Chemical Equivalence. PLoS One 2015; 10:e0130494. [PMID: 26158701 PMCID: PMC4497723 DOI: 10.1371/journal.pone.0130494] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 05/20/2015] [Indexed: 11/23/2022] Open
Abstract
There is great need to express the impacts of chemicals found in the environment in terms of effects from alternative chemicals of interest. Methods currently employed in fields such as life-cycle assessment, risk assessment, mixtures toxicology, and pharmacology rely mostly on heuristic arguments to justify the use of linear relationships in the construction of "equivalency factors," which aim to model these concentration-concentration correlations. However, the use of linear models, even at low concentrations, oversimplifies the nonlinear nature of the concentration-response curve, therefore introducing error into calculations involving these factors. We address this problem by reporting a method to determine a concentration-concentration relationship between two chemicals based on the full extent of experimentally derived concentration-response curves. Although this method can be easily generalized, we develop and illustrate it from the perspective of toxicology, in which we provide equations relating the sigmoid and non-monotone, or "biphasic," responses typical of the field. The resulting concentration-concentration relationships are manifestly nonlinear for nearly any chemical level, even at the very low concentrations common to environmental measurements. We demonstrate the method using real-world examples of toxicological data which may exhibit sigmoid and biphasic mortality curves. Finally, we use our models to calculate equivalency factors, and show that traditional results are recovered only when the concentration-response curves are "parallel," which has been noted before, but we make formal here by providing mathematical conditions on the validity of this approach.
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Affiliation(s)
- Michael Mayo
- Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS, 39183, United States of America
| | - Zachary A. Collier
- Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS, 39183, United States of America
| | - Corey Winton
- Information Technology Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS, 39183, United States of America
| | - Mark A Chappell
- Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS, 39183, United States of America
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Beck ML, Hopkins WA, Jackson BP, Hawley DM. The effects of a remediated fly ash spill and weather conditions on reproductive success and offspring development in tree swallows. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:119. [PMID: 25690609 DOI: 10.1007/s10661-015-4333-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/26/2015] [Indexed: 06/04/2023]
Abstract
Animals are exposed to natural and anthropogenic stressors during reproduction that may individually or interactively influence reproductive success and offspring development. We examined the effects of weather conditions, exposure to element contamination from a recently remediated fly ash spill, and the interaction between these factors on reproductive success and growth of tree swallows (Tachycineta bicolor) across nine colonies. Females breeding in colonies impacted by the spill transferred greater concentrations of mercury (Hg), selenium (Se), strontium, and thallium to their eggs than females in reference colonies. Parental provisioning of emerging aquatic insects resulted in greater blood Se concentrations in nestlings in impacted colonies compared to reference colonies, and these concentrations remained stable across 2 years. Egg and blood element concentrations were unrelated to reproductive success or nestling condition. Greater rainfall and higher ambient temperatures during incubation were later associated with longer wing lengths in nestlings, particularly in 2011. Higher ambient temperatures and greater Se exposure posthatch were associated with longer wing lengths in 2011 while in 2012, blood Se concentrations were positively related to wing length irrespective of temperature. We found that unseasonably cold weather was associated with reduced hatching and fledging success among all colonies, but there was no interactive effect between element exposure and inclement weather. Given that blood Se concentrations in some nestlings exceeded the lower threshold of concern, and concentrations of Se in blood and Hg in eggs are not yet declining, future studies should continue to monitor exposure and effects on insectivorous wildlife in the area.
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Affiliation(s)
- Michelle L Beck
- Department of Fish and Wildlife Conservation, Virginia Tech, 106 Cheatham Hall, Blacksburg, VA, 24061-0321, USA,
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10
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Hashmi MZ, Shen H, Zhu S, Yu C, Shen C. Growth, bioluminescence and shoal behavior hormetic responses to inorganic and/or organic chemicals: a review. ENVIRONMENT INTERNATIONAL 2014; 64:28-39. [PMID: 24361513 DOI: 10.1016/j.envint.2013.11.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 11/25/2013] [Accepted: 11/26/2013] [Indexed: 06/03/2023]
Abstract
A biphasic dose response, termed hormesis, is characterized by beneficial effects of a chemical at a low dose and harmful effects at a high dose. This biphasic dose response phenomenon has the potential to strongly alter toxicology in a broad range. The present review focuses on the progress of research into hormetic responses in terms of growth (in plants, birds, algae and humans), bioluminescence, and shoal behavior as end points. The paper describes how both inorganic and organic chemicals at a low dose show stimulatory responses while at higher doses are inhibitory. The article highlights how factors such as symbiosis, density-dependent factors, time, and contrasting environmental factors (availability of nutrients, temperature, light, etc.) affect both the range and amplitude of hormetic responses. Furthermore, the possible underlying mechanisms are also discussed and we suggest that, for every end point, different hormetic mechanisms may exist. The occurrences of varying interacting receptor systems or receptor systems affecting the assessment of hormesis for each endpoint are discussed. The present review suggests that a hormetic model should be adopted for toxicological evaluations instead of the older threshold and linear non-threshold models.
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Affiliation(s)
- Muhammad Zaffar Hashmi
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Hui Shen
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Shenhai Zhu
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China
| | - Chunna Yu
- Center for Biomedicine and Health, Hangzhou Normal University, Hangzhou 311121, People's Republic of China
| | - Chaofeng Shen
- Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
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11
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Beck ML, Hopkins WA, Jackson BP. Spatial and temporal variation in the diet of tree swallows: implications for trace-element exposure after habitat remediation. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2013; 65:575-587. [PMID: 23695717 DOI: 10.1007/s00244-013-9913-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 04/30/2013] [Indexed: 06/02/2023]
Abstract
Emerging aquatic insects play a key role in transporting aquatic contaminants into terrestrial ecosystems. Tree swallows are frequently the focus of studies examining this movement because they are thought to forage heavily on emerging aquatic insects when breeding in riparian areas. We examined the tree swallow diet to determine if trace elements from a recently remediated coal fly ash spill were moving into the terrestrial ecosystem. We collected bolus samples from adult tree swallows as they entered the nest box to feed their young. Despite strategically locating boxes in riparian areas, we found that the consumption of insects with an aquatic larval stage ranged from 28 to 75% of insects among colonies. We also found significant differences among colonies in the taxa found in bolus samples. Chironomidae (midges) were the primary emerging aquatic insects consumed by tree swallows, whereas Ephemeroptera were brought to nestlings infrequently. The consumption of insects with an aquatic larval stage, Chironomidae in particular, was positively correlated with exposure to trace elements from the spill. Bolus samples from the spill site contained greater concentrations of many trace elements compared with reference locations, but concentrations of most elements were lower than levels thought to cause reproductive impairment. These results support the hypothesis that emerging aquatic insects transport trace elements to terrestrial consumers and that Chironomidae play an important role in this movement. Our results also indicate that it is important to assess the composition of the diet and to not infer exposure to trace elements based on nesting location.
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Affiliation(s)
- Michelle L Beck
- Department of Fish and Wildlife Conservation, Virginia Tech, 100 Cheatham Hall, Blacksburg, VA 24061-0321, USA.
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Vandenberg LN, Colborn T, Hayes TB, Heindel JJ, Jacobs DR, Lee DH, Shioda T, Soto AM, vom Saal FS, Welshons WV, Zoeller RT, Myers JP. Hormones and endocrine-disrupting chemicals: low-dose effects and nonmonotonic dose responses. Endocr Rev 2012; 33:378-455. [PMID: 22419778 PMCID: PMC3365860 DOI: 10.1210/er.2011-1050] [Citation(s) in RCA: 1986] [Impact Index Per Article: 165.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 02/07/2012] [Indexed: 02/08/2023]
Abstract
For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of "the dose makes the poison," because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from the cell culture, animal, and epidemiology literature. We illustrate that nonmonotonic responses and low-dose effects are remarkably common in studies of natural hormones and EDCs. Whether low doses of EDCs influence certain human disorders is no longer conjecture, because epidemiological studies show that environmental exposures to EDCs are associated with human diseases and disabilities. We conclude that when nonmonotonic dose-response curves occur, the effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health.
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Affiliation(s)
- Laura N Vandenberg
- Tufts University, Center for Regenerative and Developmental Biology, Department of Biology, 200 Boston Avenue, Suite 4600, Medford, Massachusetts 02155, USA.
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Weech SA, Scheuhammer AM, Wayland ME. Selenium accumulation and reproduction in birds breeding downstream of a uranium mill in northern Saskatchewan, Canada. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:280-288. [PMID: 21927945 DOI: 10.1007/s10646-011-0788-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/02/2011] [Indexed: 05/31/2023]
Abstract
Selenium (Se) concentrations in aquatic invertebrates and bird eggs collected along the treated effluent receiving environment of the Key Lake uranium mill in northern Saskatchewan were significantly greater than from nearby reference areas, and in some cases (e.g., eggs of common loons--Gavia immer) were higher than commonly used thresholds for adverse reproductive effects in birds (i.e., 5 μg/g dry weight in diet; 12-15 μg/g dry weight in eggs). Mean Se concentrations in tree swallow (Tachycineta bicolor) eggs reached a maximum of 13.3 μg/g dry weight at the point of treated effluent discharge and exhibited a gradient of decreasing Se concentrations with increasing distance from the effluent discharge, probably reflecting both effluent dilution and local site fidelity by nesting swallows. In some cases, high intra-clutch variability in Se concentrations in mallard (Anas platyrhynchos) and tree swallow eggs was observed in high-Se sites, suggesting that a single egg randomly sampled from a nest in an area of higher Se exposure may not be representative of Se concentrations in other eggs from the same nest. Overall, tree swallow reproductive success was similar in both exposed and reference areas.
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Affiliation(s)
- Shari A Weech
- Minnow Environmental Inc, 101-1025 Hillside Avenue, Victoria, BC V8T 2A2, Canada.
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