Environmental/occupational Toxicology Flashcards
What are the 3 canadian ecozones?
Agricultural/ubran-based regions
Coasts
Arctic
What does movement of a chemical in the environment depend on?
Physical and chemical properties of the chemical
How can we measure and predict how a chemical will partition between environmental compartments?
Chemodynamics: the study of chemical behavior in the environment
What are the two aspects of chemodynamics?
Outside the body: release, transport, distribution within/between compartments
Inside the body: metabolism, degradation, storage, excretion, concentration
What are the environmentla compartments?
Air (atmosphere)
Water (hydrosphere)
Soil (lithosphere)
Biological systems
What are the THREE major factors that influence impact on environmental chemicals?
Persistance
Bioaccumulation/biomagnification
Toxicity
How many Persistant Organic Pollutants (POPs) are there?
A lot
What is bioaccumulation? Name an example
The accumulation of contaminants from the environment and food
(positively correlated with lipophilicity)
eg PCB is lipophilic, ends up in fat
More fat in meal, more PCB
What is a property of most persistant toxic substances?
Polyaromatic
What is the difference between biomagnification and bioaccumulation?
Bioaccumulation: accumulation of toxin in a particular organism
Biomagnification: increased concentration of toxin as you go higher up food chain
Why is there lots of PCBs found in mothers and infants of Nunavik?
Diet restricted to whale blubber, PCB bioaccumulates in fat
How do you identify hazards? (4)
What is the benchmark for toxity?
- Structure-activity relationships
- In-vitro and short-term tests
- Animal Bioassays
- Epidemiologic data
THRESHOLD OF TOXICOLOGICAL CONCERN (TTC)
What is the threshold of toxicological concern?
A complicated flowchart that answers the question: “Should we be worried about this chemical?”
How do you establish causality when evaluating occupational agents?
In vitro analyses Animal toxicology studies Human challenge studies Case reports Epidemiology studies
What is the ACGIH?
American Conference of Governmental Industrial Hygienists
What is the OSHA?
Occupational Safety and Health Administration
What is a TLV and what are three types?
Threshold Limit Values:
TLV-TWA: Time weighted average
TLV-STEL: Short term exposure limit
TLV-C: Ceiling
What are PELs?
Permissible exposure limits
What are RELs?
Recommended exposure limits
Why is it difficult to establish a causal link between illness and a job? Name three challenges
Equivalence of occupationally-induced vs non-occupational disease
Protracted latent interval between exposure and expression of disease
Multi-factorial nature of diseases of occupational origin
What are 5 approaches to prevent/control occupational hazards?
Change the process to use/produce less hazardous compounds
Automate and enclose the process to isolate the compounds
Implement administrative/work practise controls to reduce duration/intensity of exposre
Install/upgrade local exhaust system and dilution exhaust
Institute a comprehensive program for personal protective equipment use when necessary
What are the 2 main issues with aerial application of pesticides?
Very difficult to avoid drift/overspray
Even under correct conditions, trailing vortices generated by wings can disperse pesticides to untargeted areas
How long does it take to register a pesticide/assess its risk?
6-10 years (and its expensive as FUCK)
What are the four properties of pesticides that are important to test?
Bioaccumulation (particularly for fat soluble compounds)
Degradation (what’s left over time)
Toxicity (acute, chronic, aquatic, terrestrial)
Carcinogenicity (to fish, mice, rats (humans))
