Unit 4 Ecotoxicity Flashcards
What is toxicology?
The study of poisons/toxins and their effects on organisms
What is ecotoxicology?
The study of toxicology including environmental factors
What is the most common use of toxins for ecotoxical studies?
Development testing and use of pesticides
What is a persistent factor?
How long it takes for the chemical to break down. Shorter better
What’s the difference between fat solubility and water solubility?
Water soluble substances can be excreted from your body and can be easily entered into water systems where as fat soluble substances absorb into fatty substances and can build up over time
What is biomaccumulation/biomagnification?
A little bit of toxins everyday until excessive.
Exponential increase
What is a antagonistic effect?
Two or more substances cancel each other out (less toxicity)
What is a synergistic effect?
When 2 or more toxins have a pronounced effect.
What is the percentage of intended pathway to actual pathway
2% reaches where we want it to go and 98% does not
What is the grasshopper effect?
When toxins are moved to the piles through wind currants by “jumping” up or down
What is genetic based tolerance?
When an organism mutates and becomes tolerant to the toxin
How do we manage toxins?
Conduct risk assessments that describe quantity and hazards and evaluate the harm.
What is risk
Probability that an activity or exposure will be harmful.
What are the factors in evaluation of risk?
- hazard identification
- dose response assessment
- exposure assessment
- risk characterization
What is LD50 and ED 50
Lethal dose that kill 50% of the population and
Effective dose that causes specific responses to 59% of the population.
What can a dose response curve give us?
Can help identify LD50 ED50 and the threshold level
What is hazard quotient?
It is the estimate exposure and toxicity that uses the highest amount of environmental concentration and then observing the most sensitive organism in that environment
What is EEC
Exposure consintration
What is TBC
Effect concentration
What is the formula and ration for HQ
EEC/TBC=HQ
HQ>1 toxic effects
HQ<1no toxic effects
What are persistent organic pollutants (POPs)
Synthetic compounds used in manufacturing, insulators, cooling
Who is Rachel Carson?
Author of silent spring, grandmother of environmental science, raised public awareness about ddt
What is the Stockholm convention?
An organization that includes POPs management and cleaning up the dirty dozen
What is the most toxic form of mercury? Why?
Methylmurcury, organic- eaten by bacteria and entered into the food chain (fat soluble)
How is mercury released by humans?
Burning coal, smelting etc
How has the Canada mercury emissions changed since 1990?
It is 87% lower and 95% comes from the USA
What is substance agriculture?
Small production, just for the family
What is a slash and burn approach to agriculture?
Cutting then burning a forested area to use ash as fertilizer, then abandon to let the forest grow back, but the forest doesn’t grow back because all the nutrients are gone
What is industrialized agriculture?
Crop yields are enhanced through the use of large machines and large inputs of resources (cash crops)
When/what was the green revolution?
1940-1960
It was the introduction of high trials crops, chemical fertilizers, synthetic pesticides, multiple cropping, and lower production costs
What were the problems with the green revolution?
Pollution and fanatical investment for farmers and less developed land
What contributes to soil conservation?
- attributes that make the soils clump and crumble
- water retention capacity
- soil community contributing to organic layer
- Clay sand and salt vary in size to let water in
What are the 4 major components of soil and how much of each for ideal soil
5% organic material
45%minerals
25% water
25%air
What is the cation exchange capacity (CEC)
It is when clay (negatively charged) holds cations/minerals in place for plants to absorb
What are the layers of soil that has not been plowed ?
O horizon (organic) A horizon (topsoil) B horizon (subsoil) C horizon (weathered rocks/water) D horizon (parent material)
