heavy metals and

Document Sample
heavy metals and Powered By Docstoc
					   HEAVY METALS
   and Other Toxins

Daniel S. Conklin, Sr. Biologist
    The Florida Aquarium

        Peter J. Mohan
               ?
    What Are Heavy Metals?

 Term used loosely for 60 years under various
  definitions, none accepted by the International
  Union of Pure and Applied Chemistry
 For our purpose, especially mercury, copper, lead,
  cadmium, zinc, nickel, chromium, cobalt, silver,
  arsenic, vanadium, manganese, iron, tin, and
  aluminum


               1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
             Other Toxins
 Volatile organic carbons
 Concrete alkalis
 Chlorine




             1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Sources of Contaminants in
 Artificial Seawater Water
            (ASW)
   Component ingredients in ASW
    – Manufactured sea salt
          Atkinson-Bingman study
             – New water and established aquaria
    – Do it yourself sea salt
          Contaminated raw materials
          i.e., cyanide compounds, nickel
   Water for ASW
    – Municipal water supply
    – Well water


                      1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Source Water Contamination
    in Natural Seawater
   Coastal water/harbor water is often heavily
    polluted.

   Transport vessel must be carefully
    considered if offshore water is to be used.




                1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
          Other Sources of
           Contamination
 Foods offered to inhabitants
 Life support apparatus
 Building materials
 Routine trace element additions
 Atmospheric sources via rain, particulate
  matter


              1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
       Heavy Metal Analysis

   Collection technique
    – Proper sample container
    – Preservation and storage




                1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
       Heavy Metal Analysis

Quantitative and Qualitative Analysis
    – Atomic Adsorption (AA)
          Flame, gas furnace
    – Inductively Coupled Plasma(ICP)
          Atomic emission spectrometry, mass spectroscopy
 More accurate analysis at lower detection levels
  after mid 1970’s, literature values before 1975
  may be slightly inaccurate(higher)
 Experience level of operator


                     1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
       Heavy Metal Analysis
   Bench top wet chemistry
    – Most methodologies are not sensitive enough to
      detect low concentrations.
   Bioassay, signs and symptoms
    – Sea urchin bio-assay (Shimek)




                1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Active Heavy Metal Removal
– Water change
– Activated carbon
– Skimming
– Polymer technology
– Algae uptake and export
– Addition of organic molecule




             1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Passive Heavy Metal Removal
 Adsorption by oxides, carbonates, and
  chlorides
 Absorption by organisms and organic
  molecules
 Incorporation into animal tissue




             1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Factors Influencing Toxicity
   Condition of organism:
    – Age and size, previous exposure
    – Reproduction
    – Personal observation with copper application to
      fish for quarantine purposes




                 1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Factors Influencing Toxicity
Speciation and bio-availability
 Water chemistry affects speciation or form
  of metals
    – pH, salinity, hardness, dissolved oxygen
        Marine system versus freshwater system


   Temperature and light



                 1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
           Levels of Toxicity
   Physical effects on inhabitants
    – Acute
        enzyme inhibition

    – Chronic:
        chemoreception

    – Sub-lethal:
        bioaccumulation, growth, reproduction, behavior

         alteration


                  1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
          Levels of Toxicity

   Approximate decreasing order of toxicity of
    common heavy metals:
    – Mercury, cadmium, copper, zinc, nickel, lead,
      chromium, aluminum, and cobalt (Abel, 1989)




                1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
Essential Metals (or to much
     of a good thing?)

 Atleast 11 metals including copper,
 zinc, nickel, and cobalt are essential at
 appropriate concentrations but may be
 toxic at higher concentrations



            1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
         Metabolic Activity?
   Heavy metals such as mercury, silver, lead,
    tin, and arsenic are generally not required
    for metabolic activity and are toxic to the
    cell at low concentrations.




               1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
    Examples of Essential
          Metals
Respiratory pigment of many mollusks and
 higher crustaceans, haemocyanin, contains
 copper
Many enzymes contain zinc
Vitamin B12 contains cobalt
Respiratory pigment of tunicates contains
 vanadium

             1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
         Some Aquarium
          Observations

 Incident of lead poisoning in brown sharks
  (EUAC paper)
 Temporary spots as a possible sign of zinc
  stress in bull and lemon shark (Dempsey,
  personal commun.)



             1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
     How Organisms Manage
           Exposure
 Storage or excretion and as a synergistic
  solution
 Metallothioneins
 Bio-indicators, ex. shellfish
 Different organisms have different
  sensitivities



              1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
          Unique Methods
 Octopus dofleini excretes both Zn and Cu in
  the rectal fluid and urine (Potts and Todd,
  1965)
 Storage and removal of Cadmium via
  molting of exoskeleton in Lysmata
  seticaudata (Fowler and Benayoun, 1974)



             1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal
       Ignorance Was Bliss
     (at least for some of us)
   Now what do we do?
    – Much of what we know about heavy metals in
      seawater and freshwater is derived from
      literature pertaining to ecological effects.
    – Now it’s time to use this information to begin
      aquarium studies.




                 1st AQUALITY Symposium, April 2 - 7, 2004, Oceanario de Lisboa, Portugal

				
DOCUMENT INFO