Oral Health Group

General Dentistry: Environmental IQ Test

July 1, 2001
by Janice Goodman, DDS

1.Mercury can take different forms. Of the forms listed below, which is the most toxic and has the biggest impact on health and the environment?

A. Inorganic mercury

B. Elemental mercury

C. Organic Compounds (carbon containing)

D. Methylated mercury

2.You used to know this one! The components of amalgam are:

A. Silver 20-38%, tin 11-15%, copper .5-25%, zinc 0-1% and ~50% mercury

B. Silver 40-45%, copper 11-15%, tin .5-25%, zinc 0-1% and ~50% mercury

C. Silver 15-30%, zinc 11-15%, copper 5-20%,tin 0-1% and ~50% mercury.

3. When amalgam goes into the sewers it is often incorporated into “sewer sludge”. Where does this sewer sludge go?

A. It is sold as fertilizer and applied to the land

B. Incinerated

C. Disposed of in landfills

D. All of the above

4. When a dentist places or removes an amalgam filling, particles go into both the suction line and cuspidor(if in use). A. 75% of all the larger amalgam particles are caught in traps. B. 1-10% of particles which are smaller than 45 microns may be dissolved away. C. of the remaining amounts 80-99% of all the undissolved particulate amalgam will settle in 1-2 hours if left undisturbed. The true statements are:

1. A

2. A and C

3. A, B and C

5.Which of the following are correct?

A. If solid amalgam is ingested by fish (in an aquarium), mercury levels in their muscle and liver would increase.

B. Algae ingests mercury

C. There is an ever increasing concentration of mercury in fish depending on the fish size.

D. Mercury levels are now decreasing in the Great Lakes.

6.The U.S. Food and Drug Administration have stated the following in recent consumer advisories:

A. Pregnant women should not eat shark, swordfish, king mackerel or tilefish because they contain enough mercury to damage a fetus’ nervous system.

B. Young children should avoid the fish in A. also.

C. Nearly all fish contain trace amounts of mercury but longer-lived, larger fish accumulate the highest amounts of methyl mercury and pose the largest threat to people who eat them regulary. D. Canned tuna is generally produced from smaller fish and contains less mercury than a tuna steak.

E. All of the above

7.Dental amalgam under certain circumstances can change from an inorganic stable form to a more toxic methylated compound. It has been reported that certain dental line cleansers containing which product can initiate this reaction.

A. Sodium bicarbonate

B. Hydrogen peroxide

C. Sodium hypochlorate

D. Sodium perborate

8.The best organization for dentists to call for the most comprehensive information, handbooks and phone numbers regarding dental recycling and amalgam waste issues is:

A. National dental organizations (e.g. CDA)

B. Provincial dental organizations

C. Provincial dental colleges

D. Environment Canada

E. Pollution Probe

9.The flow of fresh water through a wet vacuum suction pump is approximately one gallon per minute. This is the equivalent of contaminating how many glasses of drinking water per lunch hour if an office neglects to turn off the suction when it’s not in use?

A. 100 glasses

B. 1,080 glasses

C. 10,800 glasses

10.The concentration of mercury in city rain water is:

A. .01 parts per million

B. .01 parts per billion

C. .01 parts per trillion

11.The concentration of mercury in city drinking water is:

A. 1 parts per billion

B. 1000 parts per billion

C. .01 parts per million

12.Toronto has the most stringent limit of mercury release from a dental facility of all the recent Canadian municipal bylaws. The amount of this limit is:

A. 1 parts per million

B. .1 parts per million

C. .01 parts per million

D. .05 parts per million

13.Which of the following statements are correct?

A. Environment Canada controls movement of amalgam waste for recycling and final disposal if it is crossing Canadian boarders–under the Canadian Protection Act. ( Contact: Environment Canada at 416-739-5871)

B. The Provincial Ministries of the Environment (MOE) regulates the transportation of amalgam waste within Canadian boarders. (Contact individual MOE’S. For Ontario: 416-314-4186)

C. There are no small quantity excemptions under the Export and Import of Hazardous waste Regulations as stated in the Transportation of Dangerous Goods Regulations. ( Specific questions can be directed to Carl Chenier of Environment Canada at 416-739-5867)

D. This information is new and confusing to most dentists.

E. All of the above

14.It has been estimated that dentists produce approximately 35 micrograms (.035 grams) per dentist per day of mercury into the environment. Which of the following statements are correct:

A. The World Health Organization allows from 300-500 micrograms of mercury daily, five days a week, with no side effects.

B. According to the World Health Organization, the average person will absorb 10-20 micrograms of natural occurring mercury from the environment per day.

C. The weel;y dose of mercury from 12 amalgam fillings(Berglund,1990) is 100 times less than the WHO standard. i.e. 12 average size fillings give off 1.7 micrograms of mercury per day.

D. All of the above

E. none of the above

15.This question comes straight out of the June issue of Gardening Life Magazine. All of the following are true statements.

Canada lays claim to 20% of the world’s fresh water and consumes more water than any other country in the world.

Each Canadian uses 125,000 liters per year of fresh water for household and gardening purposes (only 3% of which is used for drinking)

In the summer, half of all treated water is sprayed on lawns and gardens.

When gardens are watered at midday, about 80% of it goes to evaporation and even more water is required than usual.

Mulch on garden soil will let water percolate deeper and keep the soil moist.

Armed with this information you will most likely:

A. Be more appreciative of how lucky Canada is with regards to our most precious natural resource.

B. Be careful about adjusting timers on automatic sprinklers at home.

C. Turn off the suction when it is not in use.

D. Be prudent about how much water is allowed to run in the cuspidor.

E. All of the above

Oral Health welcomes this original article.



2. B



5.A, B & C











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