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Bioaccumulation and Biomagnifica

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Bioaccumulation and Biomagnifica Powered By Docstoc
					Activity
 As a class we are going to make our own food chain
 Each of you will be assigned a role
  either krill (60%), fish (25%), seals (14%) and killer
  whale (1%)
 We have had an algae bloom in the classroom, but for
  some strange reason the algae looks like M&Ms
 The krill eats algae, the fish eats krill, the seals eats the
  fish and the whale eats the seals
Activity
 Krill you have 45 seconds to feed on the algae, do not eat it
  instead place it inside the ziploc bag. After the time you
  will stop.
 Fish you will have 30 seconds to now feed on the krill, to
  feed on the krill you will tap them on the shoulder, and you
  will collect their M&Ms. Krill do not run in the class
 Seals you will have 15 seconds to now feed on the fish, to
  feed on the fish you will tap them on the shoulder, and you
  will collect their M&Ms. Fish do not run in the class
 Killer whales you have 5 seconds to now feed on the seals,
  to feed on the fish you will tap them on the shoulder, and
  you will collect their M&Ms. Seals do not run in the class
Activity
 All of you who were not eatend you are now to count
  the different colour of M&Ms you have
 Creature % Toxins Consumed Condition
 KRILL Any Dead
 FISH More than 20% Dead
 Seals 20-30% SickMore than 30% Dead
 Whale 20-30% SickMore than 30% Dead
 Figure this out
Definitions
 Bioaccumulation: The increase in concentration of
 a substance from the environment to the first
 organism in a food chain

 Biomagnification: The increase in concentration
 of a substance from one link in a food chain to
 another

 This is how we get a transfer of nutrients from
 one organisms to another, meaning higher order
 organisms contain more nutrients which is
 essential for growth. But this process can also be
 negative side, when harmful chemicals or
 pollutants are involved
Criteria for Biomagnification of a
Pollutant to Occur
 The pollutant or chemical must be:
   Long lived – if it is short-lived, it will be
    broken down before it becomes dangerous
   Mobile – if it will stay in one place, it is
    unlikely to be taken up by organisms
   Fat soluble – if it soluble in water, it will be
    excreted by the organism
   Biologically active – if it is not active
    biologically, it may biomagnify, but it won’t
    cause any problems
Video
 http://www.youtube.com/watch?v=E5P-UoKLxlA
 Stop at 1:35
DDT (not the wrestling move)
 DDT – dichloro-dipheny-trichloroethane
  (chlorinated hydrocarbon)
 It has a half-life of 15 years – that means if 100
  kg of DDT is used it will break down as follows:

             Year                      Amount
                                      Remaining
              0                        100 kg
              15                        50 kg
              30                        25 kg
           Continue this chart, until no DDT is left
DDT
 DDT has rather low toxicity to humans
 But
   high toxicity to insects
   If accidentally swallowed in large amounts, it can
    cause a person to become excitable, have tremors
    and seizures
   In animals, harmful effects in reproduction and in
    the nervous system
   Causes shell-thinning in birds, in particular
    carnivorous birds (raptors) such as ospreys and
    bald eagles
Biomagnification of Other
Pollutants
          Substance                     Use and Problems
PCB’s                            insulators in transformers
                                Fire retardant
                                Impairs reproduction
                                Widespread in aquatic systems

Heavy Metals                    Mercury from gold mining
Mercury, Copper, Cadmium,      Many from metal processing
Chromium, Lead, Nickel, Zinc,   May affect nervous system
Tin                             May affect reproduction

Cyanide                         Used  in leaching of gold
                                Used in fishing
                                Toxic
Mercury in Fish
 Mercury is a global contaminant because it is toxic,
  does not break down in the environment and can build
  up in living things
 some types of bacteria and fungi can change mercury
  into its most toxic form, methyl mercury. Methyl
  mercury tends to accumulate to some degree in all
  fish, but especially in predatory fish such as shark,
  swordfish, certain species of tuna
 However, human activity has increased the amount of
  mercury in the environment in several ways, including
  through a variety of combustion and industrial
  processes like coal-fired power generation, metal
  mining and smelting and waste incineration.
How this affects you
 The health effects of mercury exposure depend
  on its chemical form (elemental, inorganic or
  organic), the route of exposure (inhalation,
  ingestion or skin contact), and the level of
  exposure. Vapour from liquid elemental mercury
  and methyl mercury are more easily absorbed
  than inorganic mercury salts and can, therefore,
  cause more harm
 Methyl mercury can also be passed to the infant
  through breast milk.
How this affects you
 People who consume large amounts of fish, marine mammals
  and wild game as part of their daily diet increase their
  risk. The developing fetus and children of women who have
  consumed large amounts of fish and marine mammals during
  pregnancy are the most susceptible to health problems.
  However, exposure to methyl mercury from fis
 consumption is generally low if frequent consumers of
  canned tuna regularly choose canned albacore (white) tuna,
  their exposure to mercury could reach unacceptably high
  levels. The same concerns do not exist for canned "light"
  tuna because it contains less mercury than canned albacore
  tuna
 http://www.healthzone.ca/health/dietfitness/article/6212
  11--the-piven-principle-mercury-from-fish-can-pose-
  health-risk
Levels of Mercury in various
Fish
 High level – Swordfish, shark, king mackerel



 Medium level – Marlin, Grouper, Lobster, Halibut



 Low level – Snapper, Canned light tune (skipjack),
 trout, whitefish, crab, scallop
Where is Mercury Present ?
 Old dental fillings    Predator animals




 Thermometers           Sphygmomanometers
Summary
 Bioaccumulation and biomagnification are normal
 processes that can result in injury to an organism

 These processes can lead to a decline in population of
 birds to illnesses and deaths in humans

 In order to avoid biomagnification of undesirable
 substances, these substances should be immobile,
 water soluble, short-lived, and biologically inactive

				
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