Understanding how our Water Understanding how our Water gets Pollutedgets Polluted

You will be able to understand how You will be able to understand how and why chemicals create problems and why chemicals create problems in our water supplyin our water supply

You will understand the benefits and You will understand the benefits and risks of using chemicalsrisks of using chemicals

Thinking Questions?Thinking Questions?

Do you think all poisons to kill pests should be Do you think all poisons to kill pests should be restricted?restricted?

What happens when a chemical is over used? What happens when a chemical is over used? What “CHANGES” occur?What “CHANGES” occur?

Why would NC allow pig farms to have sewer Why would NC allow pig farms to have sewer ponds knowing the potential risk they are to the ponds knowing the potential risk they are to the environment?environment?

What are the benefits/risks to using chemicals?What are the benefits/risks to using chemicals? What CHANGES can you make in your daily habits What CHANGES can you make in your daily habits

to reduce your exposure to chemicals?to reduce your exposure to chemicals?

4 types of Water pollution4 types of Water pollutionToxins (poisons)Toxins (poisons)

4 Types of Water pollution4 Types of Water pollutionSediment (Turbidity)Sediment (Turbidity)

4 Types of Water Pollution4 Types of Water PollutionNutrients (fertilizers/waste)Nutrients (fertilizers/waste)

4 Types of Water Pollution4 Types of Water PollutionBacterial (improper waste Bacterial (improper waste

removal)removal)

5 Main Effects of any Chemical 5 Main Effects of any Chemical UsageUsage

DoseDose- amount of chemical initially sprayed or - amount of chemical initially sprayed or release to environmentrelease to environment

PotencyPotency- amount of chemical needed to - amount of chemical needed to perform desired action (lab tests determine perform desired action (lab tests determine this)this)

Exposure Time-Exposure Time- how long chemical lasts or how long chemical lasts or stays “Active”; most chemicals now designed stays “Active”; most chemicals now designed to biodegrade or break down over timeto biodegrade or break down over time

Individual Susceptibility-Individual Susceptibility- how each organisms how each organisms responds to chemical; determined by geneticsresponds to chemical; determined by genetics

ConcentrationConcentration- How chemical levels vary - How chemical levels vary throughout usage and food chain of throughout usage and food chain of ecosystem; creates biomagnification issuesecosystem; creates biomagnification issues

DDT: Why was DDT used?DDT: Why was DDT used?

DDT Spraying: Why use DDT Spraying: Why use DDT?DDT?

EVENTSpraying of DDT

Effects: DOSESpread over Wide Area

Highly EffectiveUnknown amount

Used

Effects: PotencyNever tested to

Determine amount Needed to kill

Single organismTO MUCH USED

Effects: Exposure TimeDDT never testedTo determine bio-

DegradabilityDDT FAILS TO BREAKDOWNSTAYS ACTIVE

Cause:To prevent mosquito

borne diseasesPREVENT DEATHS

Effects: IndividualSusceptibility

Individual organismsHave different tolerance

To chemicalMORE CHEM. NEEDED

TO BE STILLEFFECTIVE

Effects: Concentration:DDT levels at first small

Level gets higher In food chain

BIOMAGNIFICATION GREATLY INCREASES DDT CONCENTRATION

Cause:To Prevent Crop loss

from insectsHIGH CROP YIELD

MORE PROFIT

Reaction to Polluted WatersReaction to Polluted Waters