Toxins in our Environment, in us

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Toxins in our Environment, in us

• APES
• Fall 2006-2007

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• Why should you
• care
• about Toxins?

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We will address these topics today

• Movement, distribution, and fate of toxins
• How do we minimize the toxic effects?
• How do we measure toxicity?

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We need to consider this from three levels, or
factors

• Factors relating to the toxin itself
• Factors related to exposure to the toxin
• Factors relating to the organism

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The Toxic Agent

• Whats its composition?
• Its reactivity with the environs?
• Its solubility and state of matter (S,L,G, P)
• Presence of impurities/contaminants
• Availability of a vehicle to carry it
• Movement of agent thru body tissues/cells

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Factors Related to Exposure

• Dose received by victim
• Route, rate and site of exposure
• Duration of exposure
• Frequency of exposure
• Time of exposure (day, season,year)

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Factors Related to the Organism

• Resistance to uptake, storage, cell permeability
• Ability to metabolize, inactivate, sequester, or
  eliminate agent
• Tendency to activate other substances to toxicity
• Concurrent health issues/stresses
• Species and genetic characteristics
• Nutritional status of subject
• Age, sex, wt, immune system status, maturity

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Factors to consider when dealing with Toxins

• Solubility
• Bioaccumulation
• Biomagnification
• Persistence
• Chemical interactions

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Solubility

• As water solubility of the toxin goes up, danger
  goes up! It moves around faster
• In the body
• And in our
• World.

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Solubility

• Oil-Fat soluble toxins
• Are harder to move around
• And then once in the body
• Accumulate in the fat.
• They can just hang out
• There and do damage for a
• Long time..slowly leaking into the body.

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Bioaccumulation and Biomagnification

• Bioaccumulation
• Absorption and storage of molecules.
• Biomagnification
• The accumulation of toxins low in the tropic
  levels works its way up the food chain.

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Persistence

• Some toxins degrade rapidly, others hold their
  chemical structure.
• Some things are engineered to hold
  structurethats what we value! Its bad tho if
  they are dangerousand get out in the
  water..imagine.

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Chemical Interactions

• Antagonistic reactions
• Interference with effects of or break down other
  chemicals (antioxidants)
• Additive effects
• Effects get emphasized (lead and arsenic)
• Synergistic effects
• One substance exacerbates the effects of another
  (asbestos and smoking)

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• Research on lead and arsenic
• Asbestos study

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How can we minimize the effects?

• Metabolic degradation and excretion
• Repair mechanisms

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Your liver, your filter for toxins
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Protection built in to your body!

• Cells reproduce quickly to slough off and protect
  themselves this way.
• Irritants (smoking and drinking) reduce the
  bodys ability to do this effectively.
• We were not meant to live as long as we do thats
  why we dont have a resistance to cancer.

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How do we measure toxicity?

• Can you eat too many bananas?
• Isnt it the perfect food?

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Paracelsus-German scientist

• The dose makes the poison

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Animal Testing
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More human methods include

• Computer simulations
• Cell cultures
• We still use animal testing despite the options.
• WHY?
• Our policies are based on these tests. So
  politics runs this show.

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