Geography 2011A/B Lecture Notes - Lecture 15: Polycyclic Aromatic Hydrocarbon, Mercury Poisoning, Minamata Disease
5 May 2018
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2. Persistent Pollutants
- Non-Degradable or degrade very slowly
- Remain in the environment for years or longer
- Damage is irreversible (or reparable over decades/centuries)
* Most rapidly growing type *
- Examples:
- Pesticides (DDT, dieldrin)
- Petroleum (+ products)
- PCBs, dioxins, polyaromatic hydrocarbons
- Radioactive materials
- Metals - lead, mercury, cadmium
Toxic Contaminants (1940s)
- Organic Chemicals and Heavy Metals (lead, mercury, cadmium) are acutely toxic in small amounts
- Injurious through long term exposure in minute concentrations (leads to cancer, birth defects, genetic
mutations).
- Ex. Grassy Narrows community in North Ontario
- mercury poisoning in water and fish
- people got very sick very quickly and developed minamata disease (acute mercury poisoning –
blindness, uncontrollable movement).
- Toxic Contaminants are subject to biomagnification (bioaccumulation of toxic substances in fatty
tissue as they are passed up the food chain). Fish Consumption = humans exposed to toxic substances.
In Great Lakes:
- Toxi Cotaiats settle to the otto ad do’t degrade...
- Bottom Feeders (plankton) Small Fish Large Fish Humans/Eagles/Bears
- Toxic Contaminants biomagnify (increase in concentration) as they move up food chain
- Causes deformities in predator organisms...tumours, deformities, reproductive problems,
egg shell thinning, feminization, etc.
- Guide to Eating Ontario Sport Fish guide to avoid fish in Lakes in Ontario that have
accumulated significant amounts of toxic contaminants like mercury woman and children
younger than 15, and Natives (who rely on fish as food) are especially sensitive
3. Pollutants of Emerging Concern
- "Emerging contaminants can be broadly defined as any synthetic or naturally occurring chemical or any
microorganism that is not commonly monitored in the environment but has the potential to enter the
environment and cause known or suspected adverse ecological/human health effects. In some cases,
release of emerging chemical or microbial contaminants to the environment has likely occurred for a
long time, but may not have been recognized until new detection methods were developed. In other
cases, synthesis of new chemicals or changes in use and disposal of existing chemicals can create new
soures of eergig otaiats
- Pharmaceuticals
- Endocrine Disruptors (PCB, flame retardants, bisphenol A)
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