1. Persistence is a measure of

A. the concentration of a toxinB. 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. 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. Which type of toxin were used widely as insulators, fire retardants and lubricants between 1929 and 1977?A. BPAB. VOC’s such as

benzeneC. DDTD. PhthalatesE. PCB’s

4. PCB’s A. are water solubleB. biomagnify C. biodegrade quicklyD. have been linked to liver

cancer and learning disabilitiesE. A and BF. B and CG. B and D

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.

5. A toxin that can damage brain, spinal cord and peripheral nerves is called

A. a neurotoxinB. a mutagenC. a teratogenD. an immunosuppressantE. an endocrine disruptor

6. Examples of neurotoxins include

A. LeadB. ArsenicC. Methyl mercuryD. All of the above

7. What fraction of mercury comes from anthropogenic (human-caused) sources and what is the main source?

A. 2/3; pesticidesB. 1/10; pesticidesC. 2/3; coal-burningD. 1/10; coal-burning

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

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. BPAB. DDTC. POPD. PhthalatesE. Cadmium

10. What chemical is used in water bottles, microwave dishes, and food and beverage can liners?

A. BPAB. FormaldehydeC. DDTD. CadmiumE. Dioxin

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.

11. Effects produced from a long-term, low-level exposure is called

A. acuteB. chronicC. pathologicalD. symptomaticE. synergistic

12. Chemicals that cause changes in DNA are known as

A. teratogensB. mutagensC. antigensD. carcinogens

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.

13. The LD50 dose

A. shows a response in 50% of the population.

B. kills half of the test population.

C. has a threshold of 50%.D. is administered to 50% of

the population.

14. 50 parts per million (ppm) is equivalent to

A. 5 x 10-3 ppbB. 5 x 10-2 ppbC. 5000 ppbD. 50,000 ppbE. 500,000 ppb

Solve for equivalent “parts per” ratios through proportions.Example: 1 part per 10 = 10 parts per 100

1 = 10 10 100

To find how many ppb is equal to 50 ppm

50 = x1,000,000 1,000,000,000

x = 50,000

15. Which of the following is equivalent to ppm?

A. mg/gB. g/mgC. kg/gD. g/kgE. mg/kgF. kg/mg

In a ppm ratio, the top unit is 1 millionth the bottom unit.

1 mg is 1/1,000 of a g1 g is 1/1,000 of a kg

so 1 mg is 1/1,000,0000 of a kg

A solution that contains 1 mg of solute in 1 kg of water has a concentration of 1 ppm.

A microgram (µg) is a 1,000 of a milligram or 1,000,000 of a gram.

1 µg/ g is a concentration of 1 ppm.

1 µg/ kg is a concentration of 1 ppb.

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 organismsB. Number of organisms; timeC. Dose concentration;

percent mortalityD. Percent mortality; Dose

concentration

17. Using the graph below, determine the LD50.

A. 7.5 mgB. 20 mgC. 25 mgD. 30 mg

Perc

ent m

orta

lity

18. What is the threshold level for this toxin?

A. 30 mgB. 25 mgC. 20 mgD. 7.5 mgE. 0

The threshold level is the dosage above which harmful effects occur for a toxin.

On the previous graph, the lower doses did not cause mortality. At a concentration of approximately 7.5 mg, the mortality rate began to increase.

19. What is the TC50 for the toxin shown in the graph?

A. 0.1 µg/mLB. 9 µg/mLC. 15 µg/mLD. 80 µg/mL

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/LB. 0.08 mg/LC. 0.8 mg/LD. 8 mg/LE. 80 mg/L

Starting Concentration: 8 g/L or 8000 mg/L

1st dilution 0.8 g/L or 800 mg/L

2nd dilution 0.08 g/L or 80 mg/L

3rd dilution 0.008 g/L or 8 mg/L

4th dilution 0.0008 g/L or 0.8 mg/L

21. Which toxin is more toxic?

A. AB. B

A

B

22. Which toxin is found in many household materials such as particle board and carpeting, and can off-gas and build up in enclosed spaces?

A. DioxinB. FormaldehydeC. BPAD. Polycyclic Aromatic

Hydrocarbon

23. How prepared do you feel for the Toxicology Test?

A. I am ready to ace the toxicology test

B. I am still working on it

C. Toxin? Isn’t that an island nation in Micronesia?

1. B2. C3. D4. G5. A6. D7. C8. D9. D10. A

11.B12.B13.B14.D15.E16.C17.B18.D19.C20.C21.A22.B