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Second level
Third level
Fourth level
Fifth level
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Second level
Third level
Fourth level
Fifth level
Principles of Pharmacology and Toxicology (BIOL3020)
Section 16 Introduction to Environmental Toxicology
Stine and Brown (2006) Principles of Toxicology
Air Pollutants
Primary Pollutants
Enter atmosphere directly
Natural or man-made activity
Secondary Pollutants
Formed after chemical modification in atmosphere
Particulate Pollutants
Dust, pollen and heavy metals
Most come from combustion of organic matter
Air Pollutants
When does it cause immediate health hazard
When it reaches high levels
Caused by a weather condition called thermal inversion
Layer of warm air traps a layer of cold air on surface
Traps airborne emissions leading to high concentrations of pollutants
Health Risks
Long term exposure have been implicated in development of chronic respiratory disease
Can cause lung cancer
Can effect plant growth and survival
Gas Pollutants
Carbon Oxides
Carbon mon- and dioxides
Carbon monoxides bind with high affinity to hemoglobin
When 2 of hemoglobin get converted to carboxyhemoglobin neurological effects can be measured
At 5 , cardiac output increases
Sulfur and nitrogen oxides
Both pulmonary irritants
Released during burning of coal and petroleum products
Can react with hydroxyl radicals in atmosphere to produce sulfuric and nitric acids (acid rain)
Changes pH of lakes reduce biodiversity
Gas Pollutants
Chlorofluorocarbons (CFCs)
Used in commercial and industrial processes
Propellants in aerosol cans, refrigerants, making of styrofoams
Catalyze breakdown of ozone
One CFC can cause breakdown of 10000s of ozone molecules
Synthesis of ozone and breakdown by CFCs
O O2 O3
Cl O3 ClO O2
ClO O Cl O2
Airborne Toxicants
Heavy metals
Arsenic, mercury, lead and cadmium
Emitted from smelting (production of a metal) and other industrial applications
Pesticides
Organochlorine pesticides cause health defects and environmental problems
Bioaccumulate
Many pesticides are neurotoxic (affect the nervous system)
Many kill desirable insects or plants
Contaminate streams and lakes
Water Pollution
Organic substances
Dead and decaying plant and animal wastes
Petroleum products, solvents, pesticides, polymers
Inorganic substances
Metals, nitrates and phosphates
Biological agents
Viruses, bacteria, protozoa s and other parasites that cause disease
Suspended material
Insoluble particles of soil/rock
Radioactive material
Heat
Water Pollution (Examples)
Organic Wastes (Sewage)
If dumped into a water system aerobic bacteria may bloom
Increased respiratory activities may lead to oxygen depletion in lakes (etc)
Survival of other species may be affected
Water Pollution (Examples)
Water Pollution (Examples)
More on DTT
.
From the family of organochlorine insecticides
1945 control of mosquitoes
Serious effect on birds of prey (slow reproduction)
Damaged bird eggs
Now banned in NA
Pesticides
Enter waterways from agricultural runoff
Chlorinated hydrocarbons include DDT
Half life in environment is 2-3 years
High lipid solubility
LD50 in mammals (200 mg/kg)
Cl
Cl
CCl3
Water Pollution (Examples)
3
3
Water Pollution (Examples)
Lead
Reaches lakes as it leaches from soil as industrial runoff
Can come from lead pipes into drinking water, old paint, batteries
Cause neurological and hematological effects
Mercury
Can be methylated by microorganisms into the neurotoxicant methyl mercury
Toxic Waste
Produced as a byproduct of
Manufacturing and other industry
Consumption of manufactured goods
Mining
Agriculture
Power plant activity
Small business operations (drycleaners, paint shops, automobile service)
Laboratory research
Household activities
Categories of Waste
Majority produced by large manufactures, mining and military
Wastes include solvents (trichloroethylene, toluene and benzene)
Polycyclic aromatic hydrocarbons
Pesticides
Heavy metals (lead, chromium, arsenic)
Toxic Waste
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Is it a problem
If considered cumulatively a community of many households can generate considerable waste
Should attempt to manage waste responsibly
The Love Canal
Waste was simply disposed by burying it.
Results in landfills that can leak waste into groundwater
The Love Canal illustrates this
Lessons
Haphazard disposal is only temporary
Waste Management
Management can fall under the following categories
Reducing amount, recycling, treatment, and storage
Storage should be only temporary
Reducing emphasis in industry where disposal is becoming costly
Greater efficiency, alternatives, identify source
Waste Management
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