Understanding how our Water gets Polluted n n

Understanding how our Water gets Polluted n n You will be able to understand how and why chemicals create problems in our water supply You will understand the benefits and risks of using chemicals

Thinking Questions? n n n Do you think all poisons to kill pests should be restricted? What happens when a chemical is over used? What “CHANGES” occur? Why would NC allow pig farms to have sewer ponds knowing the potential risk they are to the environment? What are the benefits/risks to using chemicals? What CHANGES can you make in your daily habits to reduce your exposure to chemicals?

4 types of Water pollution Toxins (poisons)

4 Types of Water pollution Sediment (Turbidity)

4 Types of Water Pollution Nutrients (fertilizers/waste)

4 Types of Water Pollution Bacterial (improper waste removal)

5 Main Effects of any Chemical Usage n n n Dose- amount of chemical initially sprayed or release to environment Potency- amount of chemical needed to perform desired action (lab tests determine this) Exposure Time- how long chemical lasts or stays “Active”; most chemicals now designed to biodegrade or break down over time Individual Susceptibility- how each organisms responds to chemical; determined by genetics Concentration- How chemical levels vary throughout usage and food chain of ecosystem; creates biomagnification issues

DDT: Why was DDT used?

DDT Spraying: Why use DDT? EVENT Spraying of DDT Cause: To Prevent Crop loss To prevent mosquito from insects borne diseases HIGH CROP YIELD PREVENT DEATHS MORE PROFIT Effects: Potency Effects: Exposure Time Effects: DOSE Never tested to DDT never tested pread over Wide Area Determine amount To determine bio. Highly Effective Needed to kill Degradability Unknown amount Single organism DDT FAILS TO Used TO MUCH USED BREAKDOWN STAYS ACTIVE Effects: Individual Susceptibility Individual organisms Have different tolerance To chemical MORE CHEM. NEEDED TO BE STILL EFFECTIVE Effects: Concentration: DDT levels at first small Level gets higher In food chain BIOMAGNIFICATION GREATLY INCREASES DDT CONCENTRATION

What is Biomagnification?

Reaction to Polluted Waters