APES…Please hand in your soil APES…Please hand in your soil lab…make sure you understand lab…make sure you understand soil conservation techniques and soil conservation techniques and the difference between organic the difference between organic

and inorganic fertilizersand inorganic fertilizers

Please take out your LC-50 lab and be Please take out your LC-50 lab and be prepared to discuss. What can we prepared to discuss. What can we

conclude about the toxicity of copper conclude about the toxicity of copper sulfate?sulfate?

Factors to exploreFactors to explore BaselineBaseline ThresholdThreshold Variability of resultsVariability of results LC-50LC-50 Type of organism used and method of Type of organism used and method of

exposureexposure Persistence of substancePersistence of substance Solubility of substanceSolubility of substance Synergistic effectsSynergistic effects Antagonistic effectsAntagonistic effects

Can we apply to humans?Can we apply to humans?

It is usually unethical to test on humans so test It is usually unethical to test on humans so test organisms are used.organisms are used.

Humans differ in size, anatomy, metabolism, Humans differ in size, anatomy, metabolism, genetics and sensitivitygenetics and sensitivity

Sex, age of organism, diets, etc…have to be Sex, age of organism, diets, etc…have to be considered.considered.

Habitat-humans are terrestrial and daphnia Habitat-humans are terrestrial and daphnia aquaticaquatic

Maybe complete a similar test with Maybe complete a similar test with rats/mice/monkeys?rats/mice/monkeys?

Acute vs. chronic effectsAcute vs. chronic effects

Risk AssessmentRisk Assessment

How do we establish what is safe? How do we establish what is safe? What units do you use (ie, the dose What units do you use (ie, the dose makes the poison)?makes the poison)?

1:10 chance? 1:100? 1:1000? 1:10 chance? 1:100? 1:1000? 1:1000000?1:1000000?

Pen demo…Pen demo… Ranking risks to humans…individually Ranking risks to humans…individually

then in groups.then in groups.

Diseases…chronic vs. acuteDiseases…chronic vs. acute

How do diseases become immune to How do diseases become immune to antibiotics, herbicides and antibiotics, herbicides and pesticides?pesticides?

Natural selection-rapid reproduction Natural selection-rapid reproduction with variety. Bacteria get variety with variety. Bacteria get variety through conjugation, transformation through conjugation, transformation and transduction.and transduction.

How safe is the food you eat? How safe is the food you eat? Air you breath? Life?Air you breath? Life?

Risk assessment and acceptance (176-Risk assessment and acceptance (176-179)179)

Sick building syndrome…see figure 8.10Sick building syndrome…see figure 8.10 Complete the risk perception surveyComplete the risk perception survey Should pollution levels be set to protect Should pollution levels be set to protect

the average person in the population or the average person in the population or the most sensitive? Children/women?the most sensitive? Children/women?

Bhopal, IndiaBhopal, India

Union Carbide plant accidently Union Carbide plant accidently released the pesticide Temick and released the pesticide Temick and killed thousands of people.killed thousands of people.

Terms that relateTerms that relate

Synergistic effect: the interaction Synergistic effect: the interaction which one substance accelerates the which one substance accelerates the effects the othereffects the other

Antagonistic effect: the interaction Antagonistic effect: the interaction which one substance counteracts the which one substance counteracts the effects of the othereffects of the other

Persistence: the ability to last. Persistence: the ability to last. Persistent organic compoundsPersistent organic compounds

Complete the LC-50 labComplete the LC-50 lab

ThresholdThreshold BaselineBaseline