DOCSLIB.ORG

Bioaccumulation of Metals in Tissues of Marine Animals, Part I: the Role and Impact of Heavy Metals on Organisms

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Bioaccumulation of Metals in Tissues of Marine Animals, Part I: the Role and Impact of Heavy Metals on Organisms Pol. J. Environ. Stud. Vol. 20, No. 5 (2011), 1117-1125 Invited Article Bioaccumulation of Metals in Tissues of Marine Animals, Part I: the Role and Impact of Heavy Metals on Organisms Anna Jakimska1*, Piotr Konieczka1, Krzysztof Skóra2, Jacek Namieśnik1** 1Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology, G. Narutowicza 11/12, 80-233 Gdańsk, Poland 2Marine Station Institute of Oceanography in Hel (G215) Received: 30 May 2011 Accepted: 6 June 2011 Abstract Heavy metals contribute to the anthropogenic contamination of marine ecosystems. Some of them are essential to the life processes of organisms; others are toxic, even at low concentrations. They penetrate organ- isms via food, respiratory pathways or the skin. The extent to which metals penetrate organisms is measured by bioconcentration and bioaccumulation factors and also by their transport between organisms at different trophic levels of an ecosystem. These factors define the course of metal bioaccumulation in the environment or in organisms, their organs, and tissues. Our paper discusses the role of heavy metals in organisms at differ- ent levels of the trophic pyramid (food web) and their influence on life processes. The levels of some elements, like Zn and Cu, are regulated by metabolic processes and are important constituents of enzymes and other compounds. Other such elements, e.g. Hg, Pb, and Cd, are toxic and may adversely affect DNA and enzymatic processes, hence interfere with life processes, even though organisms possess mechanisms for the detoxifica- tion and excretion of metals. An important role in metal detoxification is performed by metallothionein (MT), which binds to toxic metals, thereby preventing organisms from harmful effects. Information about the increasing level of a metal is transmitted by the MT gene as it initiates expression regulated by zinc in order to bind MT with the metal. Elements like cadmium, copper, or mercury have a greater affinity for ligands than zinc, and will tend to dis- place it at MT binding sites. Structures from which zinc has been displaced take part in detoxification, there- by limiting the toxicity of such metals as Cd, Cu, or Hg. Keywords: bioaccumulation, heavy metals, marine organisms, metallothionein Introduction The term ‘heavy metals’ is usually applied to a group of metals and metalloids (and also their compounds) that are Elements classified as heavy metals are significant pol- strongly toxic and ecotoxic, and hence are environmental lutants of marine ecosystems [1]. The main sources of these contaminants [2]. Heavy metals can be subdivided as fol- contaminants are anthropogenic: communal sewage and lows: industrial effluents, fuel combustion, mining, and smelting. • Mn, Fe, Co, Cu, Zn, and Mo – elements essential for the growth and life cycles of organisms, but are toxic at *e-mail: [email protected] high concentrations [3] **e-mail: [email protected] • Pb, Hg, and Cd – toxic even at low concentrations 1118 Jakimska A., et al. The presence of some heavy metals in ecosystems stitute a danger to its predators. The concentration of a (including seas and oceans) can have deleterious effects metal in the tissues of a predator may be higher (bioaccu- because: mulation) or lower (biodilution) than in the tissues of its • they do not degrade and have long half-lives victims [11]. The bioaccumulation of a metal resulting from • they may bioaccumulate in living tissues, giving rise to the consumption of other organisms is characterized by the symptoms of toxicity [4] trophic transfer factor (TTF), i.e. the ratio of the concentra- Heavy metals are poorly soluble in water, tending to tion of a metal in an organism (predator) to its concentra- adsorb onto suspended particulate matter in the sea, and tion in the food that organism consumes. The TTF is useful affect marine organisms. Toxic effects do not normally for assessing the extent to which a metal has been trans- manifest themselves immediately after the toxin enters the ferred from an organism on a lower trophic level to an environment and organisms; they usually become apparent organism on a higher one. only after a few years [5]. The duration of an organism’s exposure to heavy metals has a significant effect on their bioaccumulation; sometimes, despite a relatively short The Effect of Metals on Marine Organisms exposure period, the amount of a metal deposited in an organisms may be considerable [6]. Marine ecosystems are exposed to a great variety of The processes by which metals accumulate in the tis- contaminants, among them heavy metals. As some of these sues and organs of living organisms are species-dependent can remain in the environment for a long time, they may and are related to the mechanisms of detoxification and affect organisms in the food chain as a consequence. metabolism. As a consequence, we may find a variety of Sometimes the presence of xenobiotics causes so great a organisms from the same environment having different lev- change in the environment that a return to earlier, natural els of metals [7-9]. The accumulation of heavy metals at conditions is impossible. Anthropopressure on the sea’s different levels of the trophic pyramid causes serious prob- resources is increasing: among other things, it affects the lems as far as the health of the marine environment is con- health of many organisms, leading to changes in the food cerned. In these circumstances, the selection of suitable web structure and influencing bioaccumulation in the tis- species that could be an indicator [10] of xenobiotic accu- sues of marine plants and animals [13]. mulation in the tissues and organs of plant and animals at Heavy metals affect living organisms even when their various levels of the trophic pyramid takes on a particular environmental concentrations are small. Their harmfulness significance. The use of indicator species should help to is due not only to the degree of contamination of the envi- acquire: ronment, but also to the biochemical role in metabolic • a more reliable assessment of the risks of exposure processes and the extent to which they are absorbed and • an understanding of the mechanisms of bioaccumula- excreted by marine organisms. tion and detoxification Table 1 lists information on the role of heavy metals in the life processes of organisms in different parts of the sea’s trophic pyramid. Excessive concentrations of some toxic Accumulation of Metals in Tissues and Organs metals can lead to dysfunction of the endocrine system, of of Marine Organisms reproduction, and growth [13]. Moreover, those metals that can be accumulated in the tissues and organs of organisms Many xenobiotics, also heavy metals, are accumulated may adversely affect cellular functions by interacting with in the organism. Some of them are quickly detoxified, but systemic enzymes. This can lead to disturbances of growth, the vast majority is stored in tissues and organs. The bio- reproduction, the immune system, and metabolism. concentration and bioaccumulation factors and trophic Zinc is of major importance in metabolic processes, transfer factor are measure the levels of metals retained in because it is a constituent of haemocyanin in molluscs; an organism. hence, the level of this element will be higher [65]. In par- Bioconcentration is the process, a result of which is the ticular, snails of the genus Patella take up large amounts of concentration of contaminants in an organism that is higher Zn [14], which is an essential element ensuring the proper than in the surrounding environment. This term is also functioning of many enzymes and other compounds of cru- applicable to an organism studied under laboratory condi- cial significance in metabolism. Moreover, snails also have tions, where a xenobiotic enters via the respiratory pathways a high content of iron [65], a constituent of goethite (α- or the skin. This process is characterized by the bioconcen- FeOOH). This compound is responsible for the proper tration factor (BCF), i.e. the ratio of the concentration of a functioning of the radula [14]. metal in an organism to its concentration in water [11, 12]. Unlike zinc, copper is a constituent of haemocyanin in In contrast, the bioaccumulation factor (BAF) differs crustaceans. In addition, zinc and copper levels are regulat- from BCF in that the xenobiotic concentration is the total ed by metabolic processes or homeostasis [15, 16], and amount of contaminant that has entered the organism by all their levels can be affected by numerous factors, including possible pathways, i.e. via food intake, respiratory path- short-term starvation [17]. That these two elements are cor- ways, penetration through the skin, etc. [11]. related can be explained by the fact that they are bound by It happens that the level of a metal in the tissues of one metallothionein (MT), a compound of great significance in organism does not elicit any toxic effect at all, but may con- homeostasis and in the binding and release of metals [18]. Table 1. The role of heavy metals and their influence on marine organisms. Bioaccumulation ofMetalsinTissues... 1119 Class The role and influence of heavy metals Sub- (example References phylum organisms) Cu Cd Zn Hg Pb Other metals Additional information Level regulated Mn: Regulated metabolically; Molluscs metabolically; constituent of constituent of enzymes and In large amounts (oysters, constituent of many In large amounts may cause many haemocyanin in some animals; may cause peroxida- marine snails, enzymes (e.g.
Load more

Recommended publications
  • Development of Bioaccumulation Factors for Protection of Fish and Wildlife in the Great Lakes
    National Sediment Bioaccumulation Conference Development of Bioaccumulation Factors for Protection of Fish and Wildlife in the Great Lakes Philip M. Cook and Dr. Lawrence P. Burkhard U.S. Environmental Protection Agency, Office of Research and Development, Duluth, Minnesota ioaccumulation factor (BAF) development for ap­ factors that must be considered when predicting bioaccu­ plication to the Great Lakes, and in particular for mulation from measured or predicted concentrations of the recent Great Lakes Water Quality Initiative chemicals in the water and sediments of the ecosystem. (GLWQI) effort of U.S. EPA and the respective Great Lakes The bioavailability considerations that remain, after in­ states, illustrates the importance of the linkage between corporating the influence of organism lipid, organic car­ sediments and the water column and its influence on bon in water and sediments, and trophic level into BAFfds B f exposure of all aquatic biota. This presentation included and BSAFs to reduce uncertainty for site-specific a discussion of the development and application of bioavailability conditions, are shown on the z-axis. Ba­ bioaccumulation factors for fish, both water-based BAFs sically, this residual bioavailability factor is the chemical and biota-sediment accumulation factors (BSAFs), with distribution between water and sediment which can vary emphasis on the role of sediments in bioaccumulation of between ecosystems or vary temporally and spatially persistent, hydrophobic non-polar organic chemicals by within an ecosystem. Chemical properties which influ­ both benthic and pelagic organisms. Choices of bioaccu­ ence bioaccumulation are shown on the x-axis. The mulation factors are important because they will strongly octanol-water partition coefficient (Kow) is the primary influence predictions of toxic effects in aquatic organ­ indicator of chemical hydrophobicity and bioaccumula­ isms, especially when chemical residue-based dose-re­ tion potential.
    [Show full text]
  • Lakes: Ann, Gilchrist, Grove, Leven, Reno, Villard, Smith)
    Status and Trend Monitoring Summary for Selected Pope and Douglas County, Minnesota Lakes 2000 (Lakes: Ann, Gilchrist, Grove, Leven, Reno, Villard, Smith) Minnesota Pollution Control Agency Environmental Outcomes Division Environmental Monitoring and Analysis Section Andrea Plevan and Steve Heiskary September 2001 Printed on recycled paper containing at least 10 percent fibers from paper recycled by consumers. This material may be made available in other formats, including Braille, large format and audiotape. MPCA Status and Trend Monitoring Summary for 2000 Pope County Lakes Part 1: Purpose of study and background information on MN lakes The Minnesota Pollution Control Agency’s (MPCA) core lake-monitoring programs include the Citizen Lake Monitoring Program (CLMP), the Lake Assessment Program (LAP), and the Clean Water Partnership (CWP) Program. In addition to these programs, the MPCA annually monitors numerous lakes to provide baseline water quality data, provide data for potential LAP and CWP lakes, characterize lake conditions in different regions of the state, examine year-to-year variability in ecoregion reference lakes, and provide additional trophic status data for lakes exhibiting trends in Secchi transparency. In the latter case, we attempt to determine if the trends in Secchi transparency are “real,” i.e., if supporting trophic status data substantiate whether a change in trophic status has occurred. The lake sampling efforts also provide a means to respond to citizen concerns about protecting or improving the lake in cases where no data exists to evaluate the quality of the lake. For efficient sampling, we tend to select geographic clusters of lakes (e.g., focus on a specific county) whenever possible.
    [Show full text]
  • Distribution, Occupancy, and Mercury Load in Texas Alligator Snapping
    Distribution, occupancy, and mercury bioaccumulation of alligator snapping turtles in Texas David Rosenbaum1, Christopher M. Schalk1, Daniel Saenz2 1Arthur Temple College of Forestry and Agriculture, Stephen F. Austin State University, Nacogdoches, TX; email: rosenbaudc@jac ks.sfasu.edu 2U.S. Forest Service, Southern Research Station, Nacogdoches, TX Introduction Methods Distribution Increasing anthropogenic habitat alteration and fragmentation in TX During spring and summer 2020-2021, we will Fig. 3: Distribution of M. are expected to further negatively impact freshwater systems. temminckii in TX. Points survey M. temminckii at sites in major river drainages indicate survey sites in of Texas that the species has been reported from the original survey that Animal species in these systems that have low dispersal capabilities, (Fig. 3). At each site,15 fish-baited traps will be set will be resampled from. are long-lived, and are dependent on the adult cohort for population Green-colored counties for 3 consecutive days, for a total of 45 trap nights indicate detection from stability, are vulnerable to anthropogenic factors including habitat per site (sensu Rudolph et al. 2002). 1999-2001, in the original alteration, accumulation of contaminants, and overexploitation. survey, while white Traps will be selectively placed in microhabitats • sizecounties indicate no The alligator snapping turtle (Macrochelys temminckii) exhibits these detection. Blue counties predicted to be favored by M. temminckii (see lower • ageare++ additional potential traits and is in decline throughout its range. Although not federally right quadrant of Fig. 2). survey sites for 2020- protected, it is legally protected as an S2 (imperiled) SGCN in Texas. 2021. Its last statewide distribution study occurred from 1999-2002.
    [Show full text]
  • Bioaccumulation
    BIOACCUMULATION Teacher’s Instructions: - recall food webs and food chains by asking students randomly if they can explain the concepts behind them - i.e. food chain is a path of how energy moves through organisms and a food web is many food chains hooked together - look at the food chain from Lake Winnipeg or create one that could exist in Lake Winnipeg - examples: emerald zooplankton walleye shiner emerald rainbow zooplankton walleye shiner smelt - discuss bioaccumulation by reading the Background information and use the food chain above as an example of showing how contaminants move and collect in a food chain - do the following activity Activity: - time: 30-45 minutes - materials: - each student needs: - 40 coloured tokens (such as marbles, centicubes, beads, etc.), 4 of which must be red or tagged red, the rest can be any color other than red; - 1 small paper cup; - you will need - 1 hula hoop for every 4 students; - 1 armband or headband for every 5 students (for predators) - 1 larger paper or plastic cup (about twice the size of the small cup) for every 5 students (for predators) 1 of 8 BIOACCUMULATION - procedure: - select (or have the students select) one predator and prey relationship from the food chain created above (the prey should consume something small such as minnows or zooplankton as token will represent the prey’s food) -divide the class into predators and prey (there should be about 4 times more prey than predators) - select a playing area to be a “lake”, the area should have a boundary (a gym floor works well and
    [Show full text]
  • The Influence of Ecological Processes on the Accumulation of Persistent Organochlorines in Aquatic Ecosystems
    master The influence of ecological processes on the accumulation of persistent organochlorines in aquatic ecosystems Olof Berglund DISTRIBUTION OF THIS DOCUMENT IS IKLOTED FORBGN SALES PROHIBITED eX - Department of Ecology Chemical Ecology and Ecotoxicology Lund University, Sweden Lund 1999 DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. The influence of ecologicalprocesses on the accumulation of persistent organochlorinesin aquatic ecosystems Olof Berglund Akademisk avhandling, som for avlaggande av filosofie doktorsexamen vid matematisk-naturvetenskapliga fakulteten vid Lunds Universitet, kommer att offentligen forsvaras i Bla Hallen, Ekologihuset, Solvegatan 37, Lund, fredagen den 17 September 1999 kl. 10. Fakultetens opponent: Prof. Derek C. G. Muir, National Water Research Institute, Environment Canada, Burlington, Canada. Avhandlingen kommer att forsvaras pa engelska. Organization Document name LUND UNIVERSITY DOCTORAL DISSERTATION Department of Ecology Dateofi=" Sept 1,1999 Chemical Ecology and Ecotoxicology S-223 62 Lund CODEN: SE-LUNBDS/NBKE-99/1016+144pp Sweden Authors) Sponsoring organization Olof Berglund Title and subtitle The influence of ecological processes on the accumulation of persistent organochlorines in aquatic ecosystems Abstract Several ecological processes influences the fate, transport, and accumulation of persistent organochlorines (OCs) in aquatic ecosystems. In this thesis, I have focused on two processes, namely (i) the food chain bioaccumulation of OCs, and (ii) the trophic status of the aquatic system. To test the biomagnification theory, I investigated PCB concentrations in planktonic food chains in lakes. The concentra­ tions of PCB on a lipid basis did not increase with increasing trophic level. Hence, I could give no support to the theory of bio­ magnification.
    [Show full text]
  • Bioaccumulation of Persistent Organic Pollutants in the Deepest Ocean Fauna
    BRIEF COMMUNICATION PUBLISHED: 13 FEBRUARY 2017 | VOLUME: 1 | ARTICLE NUMBER: 0051 Bioaccumulation of persistent organic pollutants in the deepest ocean fauna Alan J. Jamieson1 *†, Tamas Malkocs2, Stuart B. Piertney2, Toyonobu Fujii1 and Zulin Zhang3 The legacy and reach of anthropogenic influence is most organisms have reported higher concentrations than in nearby clearly evidenced by its impact on the most remote and surface-water species11,12. However, although these studies are inaccessible habitats on Earth. Here we identify extraordi- described as ‘deep sea’, they rarely extend beyond the continental nary levels of persistent organic pollutants in the endemic shelf (< 2,000 m), so contamination at greater distances from shore amphipod fauna from two of the deepest ocean trenches and at extreme depths is hitherto unknown. (>10,000 metres). Contaminant levels were considerably We measured the concentrations of key PCBs and PBDEs in higher than documented for nearby regions of heavy indus- multiple endemic and ecologically equivalent Lysianassoid amphi- trialization, indicating bioaccumulation of anthropogenic con- pod Crustacea from across two of the deepest hadal trenches — the tamination and inferring that these pollutants are pervasive oligotrophic Mariana Trench in the North Pacific, and the more across the world’s oceans and to full ocean depth. eutrophic Kermadec in the South Pacific. Two endemic amphi- The oceans comprise the largest biome on the planet, with the pods (Hirondellea dubia and Bathycallisoma schellenbergi) were deep ocean operating as a potential sink for the pollutants and sampled from the Kermadec between 7,227 and 10,000 m, and one litter that are discarded into the seas1.
    [Show full text]
  • Bioconcentration, Bioaccumulation, and the Biomagnification in Puget
    Jason E. Hall Bioconcentration, Bioaccumulation, and Biomagnification in Puget Sound Biota: Assessing the Ecological Risk of Chemical Contaminants in Puget Sound The following piece is republished from the UWT Journal on the Environment, an electronic, peer-reviewed journal designed to provide students with a forum in which to publish and read primary and secondary research, reports on conferences and events, and ideas and opinions in the environmental sciences and studies. Tahoma West encourages submissions that deal with scientific and social matters. Note: For the tables referred to in this article please see Journal of the Environment: <http://courses. washington. edu/uwtjoe/>. Introduction: Puget Sound has a large urban and rural human population, which currently exceeds 3 million, and many industrialized ports and shorelines that provide numerous sources of non-point and point source pollution to Puget Sound (Konasewich et al. 1982). Hundreds of poten­ tia lly toxic chemicals are present in Puget Sound sediments (Matins et al. 1982, NOAA and WSDE 2000, Konasewich et al. 1982, and Lefkovitz et al. J 997). As of 1982, J 83 organic compounds had been identified in Puget Sound sediments, biota, and water (Konasewicb et al. 1982). Although chemical contaminants and heavy metals are present in sedi­ ments throughout Puget Sound, these pollutants are generally greatest in number and concentration within the sediments and embayments that are adjacent to the most populated and industrialized areas, such as Elliot Bay, Commencement Bay, and Sinclair Illlet (Malins et al. 1982, Lefkovitz et aJ. 1997, Konasewich et al. 1982, and NOAA and WSDE 2000). However, the distribution and concentrations of chemical contami­ nants and heavy metals in Puget Sound generally reflect their source.
    [Show full text]
  • Estimating the Environmental Behavior of Inorganic and Organometal Contaminants: Solubilities, Bioaccumulation, and Acute Aquatic Toxicities1
    Estimating the Environmental Behavior of Inorganic and Organometal Contaminants: Solubilities, Bioaccumulation, and Acute Aquatic 1 Toxicities By Dr. James P. Hickey ABSTRACT The estimation of environmental properties of inorganic species has been difficult. In this presentation aqueous solubility, bioconcentration and acute aquatic toxicity are estimated for inorganic compounds using existing Linear Solvation Energy Relationship (LSER) equations. Many estimations fall within an order of magnitude of the measured property. For complex solution chemistry, the accuracy of the estimations improve with the more complete description of the solution species present. The toxicities also depend on an estimation of the bioactive amount and configuration. A number of anion/cation combinations (salts) still resist accurate property estimation, and the reasons currently are not understood. These new variable values will greatly extend the application and utility of LSER for the estimation of environmental properties. LSER ESTIMATES ENVIRONMENTAL The Linear Solvation Energy Relationship PROPERTIES OF INORGANIC (LSER) developed by Kamlet and others (1987, COMPOUNDS 1988) for neutral organic compounds can be a useful predictive tool, quite suitable for Researchers, manufacturers, and regulating environmental property estimations (Hickey and agencies must evaluate properties for chemicals others,1990 and Hickey,1996 compile most of the that are either present in or could be released into Kamlet and others LSER references). In LSER, the environment, many of these persistent and the solution behavior of a substance (e.g., bioaccumulative. The routine use of more than solubility, bioaccumulation, and toxicity) is 70,000 synthetic chemicals stresses the need for directly related to several aspects of its chemical this information. However, minimal physical structure.
    [Show full text]
  • Bioaccumulation, Biodistribution, Toxicology and Biomonitoring of Organofluorine Compounds in Aquatic Organisms
    International Journal of Molecular Sciences Review Bioaccumulation, Biodistribution, Toxicology and Biomonitoring of Organofluorine Compounds in Aquatic Organisms Dario Savoca and Andrea Pace * Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF), Università Degli Studi di Palermo, 90100 Palermo, Italy; [email protected] * Correspondence: [email protected]; Tel.: +39-091-23897543 Abstract: This review is a survey of recent advances in studies concerning the impact of poly- and perfluorinated organic compounds in aquatic organisms. After a brief introduction on poly- and perfluorinated compounds (PFCs) features, an overview of recent monitoring studies is reported illustrating ranges of recorded concentrations in water, sediments, and species. Besides presenting general concepts defining bioaccumulative potential and its indicators, the biodistribution of PFCs is described taking in consideration different tissues/organs of the investigated species as well as differences between studies in the wild or under controlled laboratory conditions. The potential use of species as bioindicators for biomonitoring studies are discussed and data are summarized in a table reporting the number of monitored PFCs and their total concentration as a function of investigated species. Moreover, biomolecular effects on taxonomically different species are illustrated. In the final paragraph, main findings have been summarized and possible solutions to environmental threats posed by PFCs in the aquatic environment are discussed.
    [Show full text]
  • Chemical Toxicity of Plastics Pollution to Aquatic Life and Aquatic-Dependent Wildlife
    United States EPA-822-R-16-009 Environmental Protection December 2016 Agency State of the Science White Paper A Summary of Literature on the Chemical Toxicity of Plastics Pollution to Aquatic Life and Aquatic-Dependent Wildlife Photographs courtesy of the National Oceanic and Atmospheric Administration (http://marinedebris.noaa.gov/) U.S. Environmental Protection Agency Office of Water Office of Science and Technology Health and Ecological Criteria Division [this page intentionally left blank] Page 2 of 50 Authors (alphabetical) Joe Beaman, Office of Water, Office of Science and Technology, Washington DC (co-lead) Christine Bergeron, Office of Water, Office of Science and Technology, Washington DC (co-lead) Robert Benson, Office of Water, Office of Watersheds Oceans and Wetlands, Washington DC Anna-Marie Cook, EPA Region 9, Superfund, San Francisco, CA Kathryn Gallagher, Office of Water, Office of Science and Technology, Washington DC Kay Ho, Office of Research and Development, Atlantic Ecology Division, Narragansett, RI Dale Hoff, Office of Research and Development, Mid Continent Ecology Division, Duluth MN Susan Laessig, on detail to the Office of Water. Home office: Office of Chemical Safety and Pollution Prevention, EPA HQ, Washington DC Page 3 of 50 Notices This document provides a summary of the state of the science on the potential chemical toxicity of ingested plastic and associated chemicals on aquatic organisms and aquatic-dependent wildlife. While this document reflects EPA’s assessment of the best available science for plastics pollution, it is not a regulation and does not impose legally binding requirements on EPA, states, tribes, or the regulated community, and might not apply to a particular situation based upon the circumstances.
    [Show full text]
  • The Bioaccumulation of Methylmercury in an Aquatic Ecosystem
    July 2, 2010 11:36 Proceedings Trim Size: 9in x 6in methylmercury THE BIOACCUMULATION OF METHYLMERCURY IN AN AQUATIC ECOSYSTEM N. JOHNS, J. KURTZMAN, Z. SHTASEL-GOTTLIEB, S. RAUCH AND D. I. WALLACE∗ Department of Mathematics, Dartmouth College, HB 6188 Hanover, NH 03755, USA E-mail: [email protected] A model for the bioaccumulation of methyl-mercury in an aquatic ecosystem is described. This model combines predator-prey equations for interactions across three trophic levels with pharmacokinetic equations for toxin elimination at each level. The model considers the inflow and outflow of mercury via tributaries, precipitation, deposition and bacterial methylation to determine the concentration of toxin in the aquatic system. A sensitivity analysis shows that the model is most sensitive to the rate of energy transfer from the first trophic level to the second. Using known elimination constants for methyl mercury in various fish species and known sources of input of methyl mercury for Lake Erie, the model predicts toxin levels at the three trophic levels that are reasonably close to those measured in the lake. The model predicts that eliminating methyl mercury input to the Lake from two of its tributary rivers would result in a 44 percent decrease in toxin at each trophic level. 1. Introduction Toxins that enter an ecosystem are generally observed to be more concen- trated per unit of biomass at higher trophic levels. This phenomenon is known as \bioaccumulation". Organisms can take up a toxic substance through lungs, gills, skin or other direct points of transfer to the environ- ment. Predators, however, have a major source of toxin in their prey.
    [Show full text]
  • Abstract the Impact of a Benthic Omnivore on The
    ABSTRACT THE IMPACT OF A BENTHIC OMNIVORE ON THE BIOMAGNIFICATION OF MERCURY IN TOP-PREDATOR FISH by Anna Marie Bowling Crayfish, as benthic omnivores, have the potential to be a link between the benthic and pelagic systems by feeding on fish carcasses and being prey to top-predator fish. The objective of this research was to investigate the impact of crayfish on the biomagnification of methylmercury (MeHg) in top-predator fish, by combining a field study, controlled laboratory studies, and a mathematical model. The results of the field study were inconclusive and this was mainly due to the fact that all sites had the same relative abundance of crayfish and that we were not able to collect all species of top-predator fish. Laboratory experiments supported our prediction that largemouth bass would assimilate MeHg more efficiently from MeHg-dosed crayfish than from MeHg-dosed artificial food. Model projections of laboratory results supported our prediction that MeHg biomagnification would be highest in the presence of a feedback cycle between crayfish and top-predator fish. THE IMPACT OF A BENTHIC OMNIVORE ON THE BIOMAGNIFICATION OF MERCURY IN TOP-PREDATOR FISH A Thesis Submitted to the Faculty of Miami University in partial fulfillment of the requirements for degree of Master of Science Department of Zoology by Anna Marie Bowling Miami University Oxford, OH 2009 Advisor Dr. James T. Oris Reader Dr. Lawrence W. Barnthouse Reader Dr. Chad R. Hammerschmidt Reader Dr. David J. Berg TABLE OF CONTENTS CHAPTER 1: INTRODUCTION………………………………………………………...........1 CHAPTER 2: METHODS…………………………………………………………………......4 CHAPTER 3: RESULTS…………………………………………………………………......14 CHAPTER 4: DISCUSSION…………………………………………………………….......18 CHAPTER 5: REFERENCES……………………………………………………………......24 CHAPTER 6: TABLES………………………………………………………………............31 CHAPTER 7: FIGURES…………………………………………………………………......35 i i LIST OF TABLES Table 1.
    [Show full text]