1. 1. Persistence is a measure of A.the concentration of a toxin B.the time it takes for a toxin to degrade. C.how chemically reactive a toxin is. D.how harmful a toxin is to an organism.

2. 2. The endocrine system is the system that A.fights infectious disease. B.breaks down toxins in the body. C.sends chemical messages throughout the body. D.sends sensory input to the brain.

3. 3. Which type of toxin were used widely as insulators, fire retardants and lubricants between 1929 and 1977? A.BPA B.VOC’s such as benzene C.DDT D.Phthalates E.PCB’s

4. 4. PCB’s A.are water soluble B.biomagnify C.biodegrade quickly D.have been linked to liver cancer and learning disabilities E.A and B F.B and C G.B and D

5. PCB’s are one of the POP’s (Persistent Organic Compounds). They do not degrade easily so PCB’s used decades ago are still in the environment. PCB’s are fat soluble so they bioaccumulate (remain in body tissue) and can therefore be biomagnified throughout the food chain.

6. 5. A toxin that can damage brain, spinal cord and peripheral nerves is called A.a neurotoxin B.a mutagen C.a teratogen D.an immunosuppressant E.an endocrine disruptor

7. 6. Examples of neurotoxins include A.Lead B.Arsenic C.Methyl mercury D.All of the above

8. 7. What fraction of mercury comes from anthropogenic (human-caused) sources and what is the main source? A.2/3; pesticides B.1/10; pesticides C.2/3; coal-burning D.1/10; coal-burning

9. 8. Humans can be exposed to mercury through A.Consuming fish, esp. top-consumer fish like tuna. B.Inhaling mercury vapors. C.Eating beef and other red meat D.Both A and B

10. 9. A chemical used to soften polyvinyl chloride (PVC) plastic and as a solvent in many consumer products like hair spray, body lotion and shampoo is A.BPA B.DDT C.POP D.Phthalates E.Cadmium

11. 10. What chemical is used in water bottles, microwave dishes, and food and beverage can liners? A.BPA B.DDT C.Cadmium D.Lead

12. Both phthalates and BPA are endocrine disruptors. Both have recently been banned from products for infants.- Phthalates were banned as of 2010 for baby toys and BPA was banned from use in baby bottles and cans of baby formula. But both chemicals are in use in many other products.

13. 11. Effects produced from a long-term, low-level exposure is called A. acute B.chronic C.pathological D.symptomatic E.synergistic

14. 12. Chemicals that cause changes in DNA are known as A.teratogens B.mutagens C.antigens D.carcinogens E.gametogens

15. Mutagens may increase the risk of cancer because mutations But not all carcinogens cause mutations in genes- may promote the growth of cancer cells. So mutagen is the correct term for a substance that increases the rate of mutations.

16. 13. The LD50 dose A. shows a response in 50% of the population. B.kills half of the population. C.has a threshold of 50%. D.is administered to 50% of the population.

17. 14. 50 parts per million (ppm) is equivalent to A.5 x 10 -3 ppb B.5 x 10 -2 ppb C.5000 ppb D.50,000 ppb E.500,000 ppb

18. 15. Which of the following is equivalent to ppm? A.mg/g B.g/mg C.kg/g D.g/kg E.mg/kg F.kg/mg

19. 16. If the graph is a dose-response curve, what might be the labels of the x and y axes, respectively A.Time; number of organisms B.Number of organisms; time C.Dose concentration; percent mortality D.Percent mortality; Dose concentration

20. 17. Using the graph below, determine the LD50. A.7.5 mg B.20 mg C.25 mg D.30 mg

21. 18. What is the threshold level for this toxin ? A.30 mg B.25 mg C.20 mg D.7.5 mg E.0

22. 19. What is the TC50 for the toxin shown in the graph? A.0.1 µg/mL B.9 µg/mL C.15 µg/mL D.80 µg/mL

23. 20. If a chemical with a concentration of 8 g/L is diluted in a serial dilution that is a 10 fold dilution for each step, what is the concentration after the fourth dilution? A.0.008 mg/L B.0.08 mg/L C.0.8 mg/L D.8 mg/L E.80 mg/L

24. Starting Concentration: 8 g/L or 8000 mg/L 1 st dilution 0.8 g/L or 800 mg/L 2 nd dilution 0.08 g/L or 80 mg/L 3 rd dilution 0.008 g/L or 8 mg/L 4 th dilution 0.0008 g/L or 0.8 mg/L

25. 21. Which toxin is more toxic? A.A B.B A B

26. 1.B 2.C 3.D 4.G 5.A 6.D 7.C 8.D 9.D 10.A 11.B 12.B 13.B 14.D 15.E 16.C 17.B 18.D 19.C 20.C