Fluoride In Drinking Water RoyCEU.com

What type of cartridges should be used in chemical respirators used for handling fluoride additives?
1. Cartridges for silica dust
2. Cartridges for acid gases
3. Cartridges for high moisture applications
4. Simple dust masks will suffice
What is the term used to describe the brown staining of teeth due to elevated fluoride levels?
1. Remineralization
2. Mottling
3. Fluoridation
4. Fluorspar
What is the pH of hydrofluosilicic acid, that may lower the pH of poorly buffered potable water?
1. 1.2
2. 2.6
3. 3.2
4. 5.0
Which pump draws in and expels liquid as a result of the alternate filling and emptying of a closed chamber?
1. Positive displacement
2. Centrifugal
3. Turbine
4. Magnetic
What is the maximum contaminant level (MCL) for fluoride?
1. 1.0 mg/l
2. 2.0 mg/l
3. 3.0 mg/l
4. 4.0 mg/l
What is the main reason why sodium fluoride is ideal for use in saturators?
1. 4% solubility
2. Ease in feeding chemical
3. Ease in feeding chemical
4. Cost
When using activated alumina (AA) to remove fluoride what is the required an empty bed contact time [EBCT]?
1. At least 5 minutes
2. At least 10 minutes
3. At least 30 minutes
4. At least 30 minutes at peak flow
What is a sign that someone has had an acute toxic exposure or poisoning from fluoride?
1. Ringing of the ears
2. Loss of vision
3. Loss of taste
4. Nose bleeds
When ingested in drinking water, what percentage of fluoride is retained in the mouth?
1. 20%
2. 30%
3. 40%
4. 50%
What point of use treatment process is EPA approved to obtain fluoride compliance in small water systems?
1. Lime softening
2. 5 micron filtration
3. Reverse Osmosis
4. Distillation
Which one is not a basic compound commonly used for fluoridating drinking water supplies?
1. Sodium fluoride
2. Sodium silicofluoride
3. Hydrofluosilicic acid
4. Sulfamic Acid
What does the term “fortified” mean when discussing hydrofluosilicic acid?
1. Mineral deposits are added to stabilize the acid
2. Hydrofluoric acid is removed from the hydrofluosilicic acid
3. Hydrofluoric acid is added to it to prevent the formation of silica precipitate
4. Transport and storage containers are double walled
What is another way to limit backsiphonage besides installing a mechanical backflow device?
1. Decrease solution feed line by 40% of pump discharge orifice
2. Maintain injection point higher than the elevation of the fluoride liquid level in storage
3. Create loop in chemical discharge line before chemical injection
4. Ensure negative vacuum at point of chemical injection
What must be done when the solution water for a fluoride saturator has a hardness greater than 50 ppm?
1. Add acid to depress the pH
2. Increase backwash rates
3. Increase fluoride bed depth
4. Soften the water supply to reduce the hardness
Which NSF/ANSI standard limits a chemical or product’s contribution of contaminants to drinking water applications?
1. NSF/ANSI standard 61
2. NSF/ANSI standard 60
3. NSF/ANSI standard 100
4. NSF/ANSI standard 4E
Why does the CDC recommend against the dilution of hydrofluosilicic acid?
1. To avoid the formation of a precipitate of silica
2. Safety concerns for operators
3. Cost effectiveness
4. Chemical effectiveness
What is the only toxic effect that will result from low level exposure to fluoride over a prolonged period of time?
1. Mottling of teeth
2. Skeletal Fluorosis
3. Hair loss
4. Arthritis
What sign would indicate to the operator that the storage tank vent line may be faulty?
1. Yellow vapors rising to the ceiling
2. Green discoloration (manganese hydroxide) on pipes
3. White vapors from piping
4. A fine white powder (silica) covering the pipes
What is generally installed on metering pumps to avoid accidental overfeeding of fluoride?
1. Anti-siphon valves
2. Swing checks
3. Single check valves
4. Calibration columns
What is the U.S. Public Health Service’s final recommendation for the optimal level of fluoride in community water systems?
1. 0.7 ppm
2. 1.0 ppm
3. 2.0 ppm
4. 4.0 ppm