Download ENSC 201* Winter 2005 Winn ENSC 201 Natural chemical hazards Louise Winn

ENSC 201* Winter 2005 Winn
Natural chemical hazards:
ENSC 201
Any type of chemical hazard caused by earth’s natural processes
Geological hazards:
-earthquakes, volcanoes, landslide
Natural chemical hazards
Weather/climate:
-hurricanes, tornadoes, wildfires, avalanches
Louise Winn
School of Environmental Studies
Rm 3127, BioSciences Complex
[email protected]
Biological hazard:
-plant toxins, bacterial toxins, aflatoxin, snake venom,
Environmental Toxicology. D.A. Wright and P. Welbourn.
Cambridge Press, 2002
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Forest Fires
Volcanoes
Significant force for environmental change
• Primary: direct contact with the eruption
and its material
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• Carbon dioxide
• Methane
• Nitrous oxide
Lava, ash-respiratory-also efficient at grabbing and
holding molecules of gas like sulfuric acid ∴ can
release these gases into the ground killing crops
and upsetting the chemistry of ground water
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Landslides (water combining with ash)
Iceland-lava melts ice
Climate change
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• SO2 + H2O ⇒ H2SO4
– Stays aloft for 2-3 years, cooling effect
of 0.2-0.3C, can shorten the growing
period by 1 week
Trap heat
• Smoke and aerosol
• Secondary: effects that arise from
products or derivatives of the eruption
Cooling effect-trap and block
sunlight
Indonesia-1997 released as many
greenhouse gases as all the cars and
power plants in Europe emit in an
entire year
Soames Summerhays/Photo Researchers, Inc.
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Definitions
Toxic effects of plants
• Toxin:
toxic substance produced by plants, animals,
fungi or bacteria (biological)
• Different portions of the plant often contain different
concentrations of a chemical
• Age
• Climate and soil
• Genetic differences within a species
• Toxicant:
toxic substance produced as a result of human
activity
• EXPOSURE
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• Xenobiotic: compounds not known to occur in nature
» Foreign chemical
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Major part of diet
Agriculture
Plant contamination in food
Accidental ingestion
Herbal medicines
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ENSC 201* Winter 2005 Winn
Toxic effects of plants
Discourage herbivores and inhibit bacteria or fungal pathogens
Bacterial toxins
• Foxglove
• Lipopolysaccharides-endotoxins-associated with the cell
wall
• Exotoxin: soluble proteins secreted by living bacteria
– Digitalis purpurea
– Digoxin
• Strengthens heart contraction, used to treat congestive heart failure
– Bacterial protein toxins are the most powerful human poisons
known
• Strychnine
– Strychnos nux-vomica
– Causes powerful convulsions
– Used as a pesticide
• Diphtheria toxin
– Corynebacterium diphtheriae
– Inhibits protein synthesis
• Ricin
– Ricinus communis
– Castor bean plant, seeds that are poisonous-ricin is water soluble therefore
not in oil
– When ingested, ricin causes severe gastrointestinal symptoms followed by
vascular collapse and death- acts by inhibiting protein synthesis
• Anthrax toxin
– Bacillus anthracis
• Poison ivy-toxicodendrol, sticky sap
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Fungal Toxins
Toxic Effects of Animals
• Venom: proteolytic enzymes, blood coagulation, cardiac and
pulmonary dynamics
snake
frog
Spiders
• Mushroom poisoning (Amanita muscaria, Psilosybe)
-Hallucinogenic-psilocibin, psilocin
-Muscimol and ibotenic acid
proteolytic enzymes
blood coagulation
cardiac and pulmonary dynamics
destabilization of cell membranes
• Aflatoxin
– Aspergillus flavus
– Corn, peanuts, cotton seed
– Necrosis (cell death) and cancer in animals
• Puffer fish
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• Ergot Alkaloids
– Infect grasses/grains/rye
– Produce mycotoxin - ergotoxine
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Tetradodoxin
Neurotoxin-Synaptic transmission
Death following paralysis
Found in roe, liver, intestine, and skin BUT not meat
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• Mussels and domoic acid
• Toxin produced by marine algae
• Part of structure is similar to glutamic acid
• Neurotransmission-memory loss, coma, seizures
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