PUBH 3108 Midterm

Flashcards for PUBH 3108 midterm material

Why should untreated surface water never be used for drinking?

Exposure to the environment will most likely cause water to contain microorganisms, organic debris, animal feces, and chemical/physical hazards.

What is a microcystin?

A hepatotoxin (liver toxin) produced by blue-green algae

What are four things that influence water quality?

Geology, microbial growths, the age/state of a body of water, the nutrient level/microbiological activity

Name and explain the three trophic levels of water.

1. Oligotrophic: low nutrients, low microbial activity

2. Mesotrophic: Moderate nutrients, moderate microbial activity

3. Eutrophic: high nutrients, high microbial activity (also comes with high turbidity, colour, etc.)

Name 5 potential sources of contamination in outdoor water.

1. Wastewater discharge

2. Industrial discharge

3. Agricultural runoff

4. Landfill leachate

5. Recreational activities

How many species of algae are thought to exist?

21,000

True or false: Algae can live in fresh, brackish or saline water, and tolerate a wide variety of pH levels as long as the temperature range is between 10°C and 30°C.

False, algae can survive in these conditions at a wide range of temperature extremes.

Name the three kinds of algal controls.

1. Buffer zones

2. Algal control (ex. copper sulfate pentahydrate)

3. Destratification and aeration

What is the primary cause of groundwater pollution?

Organic chemicals such as benzene and gasoline

Why is remediation of groundwater when contaminated so difficult? (2)

1. Anaerobic conditions in aquifers make breakdown of contaminants slow, allowing them to survive for long periods

2. Dilution, microbial activity, surface tension and attraction to soil particles can modify, immobilize or attenuate the movement of pollutants, making them difficult to eradicate

Name 4 examples of pools that fall under aquatic facility guidelines.

1. Swimming pools (not counting single family home or one that is drained, cleaned and refilled after each use by an individual)

2. Flow through pools

3. Portable pools

4. Wading pools

5. Water spray pad/splash pad

6. Water park

7. Whirlpool/spa/therapeutic pool

8. Leisure rivers

What are 5 kinds of health risks associated with pools?

1. Drowning/near-drowning

2. Impact injuries (diving, water slides, etc.)

3. Physiological (heat exposure, etc.)

4. Infection

5. Poisoning (long-term of short-term)

Name 5 fecal pathogens that might be spread in water and their exposure route.

1. E. coli

2. Shigella

3. Norovirus

4. Giardia

5. Cryptosporidium

Ingestion for all

Name 2 non-fecal pathogens that may be spread through water and their exposure route.

1. Pseudomonas (absorption or inhalation)

2. Legionella (Inhalation)

What water-spread bacteria causes skin rashes and/or swimmer’s ear, with hot tubs and warm water being it’s ideal environment?

Pseudomonas aeruginosa

What two diseases does Legionella cause and which is more serious?

Legionnaire’s disease (more serious), Pontiac fever

True or false: A pool must have a responsible supervisor on payroll, but due to the high salary they command many pools will have a contracted responsible supervisor and a full time qualified operator.

False, qualified operator is the one who is required and may be contracted, where as a responsible supervisor must be on site and able to test water quality and contact the QO

How long can the following organisms live at 1ppm free available chlorine, pH 7.5 and 25°C: E. coli, Hepatitis A, Giardia, Cryptosporidium.

E. coli: Less than 1 minute

Hepatitis A: ~16 minutes

Giardia: ~45 minutes

Cryptosporidium: ~15,300 minutes or 10.6 days

True or false: Pools with the chlorine stabilizer cyanuric acid require less time to disinfect pathogens.

False, they need more time

Define disinfection by-product in pools.

The oxidation of waterborne organic compounds by chlorine (creating chloramines)

What are four reasons a pool may have high chloarmine levels?

1. Poor pool maintenance/operation

2. Unhygienic behaviour from bathers

3. Water aeration (diving, jets, etc.)

4. Improper or ineffective ventilaion

Likely to always be a combination of factors

What can high chloramine levels at a pool cause? (6)

1. Chlorine smell

2. Eye irritation

3. throat irritation

4. nausea

5. light-headedness

6. asthma attacks

What tragedy lead to the enshrinement into law of anti-entrapment devices on pool drains?

The death of Virginia Grahame Baker (7 y/o) in 2002

True or false: biofilms must be scrubbed to be removed.

True

What is the proper way to mix chemicals into water?

Add chemicals to water, never water to chemicals to avoid splashing. Never mix chemicals prior to mixing with water

What are 5 daily records that should be kept at a pool?

1. Disinfection levels of FAC, TC, CC, bromine and pH

2. Daily attendance

3. Make-up water reading

4. Incidents (emergencies, fecal release, etc.)

5. Operating pressures of the recirculation pump and filters

What 2 weekly reports should be kept at a pool?

1. Cyanuric acid usage and level(if used)

2. Preventative maintenance

What monthly report should be kept at a pool?

Results of full pool inspections

What are 4 ways to promote patron hygiene at pools?

1. Signage

2. Policies

3. Public education

4. Pictograms

What does GFCI stand for and what are they used for in pools?

Ground Fault Circuit Interrupter, used to automatically shut off circuits if there is an electrical leak that could lead to a shock. Needed for underwater lighting or any electrical fixtures/outlets within 3m of the pool surface

Pool basins should be light in colour except for:

Markings, such as depth markings of underwater step treads

What are 3 requirements for depth markings in pools?

1. Located above the water surface on a walkway or wall

2. 30cm/1foot increments between the shallow depth and the point of break

3. Must be at least 10cm/4in in height and in Arabic numerals

True or false: Pools often use pool vacuums as they can be used to clean while there are patrons in the pool.

False, pool vacuums must be used when the pool is closed

Why must starting blocks be covered or removed when practice/competitions are not in session?

To deter recreational use

What should training regarding a new aquatic play feature (ex. slide, tarzan rope, etc.) include? (5)

1. Operation

2. Supervision requirements

3. Emergency procedures

4. Preventative maintenance

5. Cleaning

True or false: Water used to fill a pool must be potable, but once it is in the pool it is no longer potable.

True

What is the simplest way to prevent water backflow through a recirculation system?

An air gap

What substances in pools must be diluted with fresh make up water as they can’t be removed through treatment? (2)

Total dissolved solids, Cyanuric acid

According to WHO in 2006, what is the recommended dilution rate of fresh water per bather in pools?

30L/bather

What is the black disc test in pool maintenance?

A test involving a 150mm black dot on a 450mm white background used to measure water clarity/turbidity.

Besides filtration, what are 4 other methods for controlling turbidity in a pool?

1. Flocculant

2. clarifiers

3. UV

4. Ozone

Why do spas and hot tubs often have a higher contamination load than swimming pools? (2)

1. Less water volume per person

2. Higher water temperatures

When should a spa with less than 4000 liters of water drain and replace all water within the pool?

When the TDS is 1500ppm greater than what it was at start-up, with the water replacement interval being less than or equal to the number of days from last replacement.

Define primary disinfection.

Killing bacteria, viruses, and parasites in a way that leaves a residual.

Name a kind of secondary disinfection, and how does it differ from primary disinfection?

UV or Ozone, differs because it does not have to leave a measurable residual to indicate that it’s working.

What is the most common kind of primary disinfectant?

Chlorine

How do you calculate total chlorine?

Total chlorine = combined chlorine + free available chlorine

Define free available chlorine (FAC).

Chlorine available in water to deactivate disease causing organisms.

True or false: Hypochlorus acid (a weak acid made when chlorine hits water) is 80x more effective than the hypochlorite ion as a disinfectant.

True

How many ppm of FAC should be maintained in:

a. Un-stabilized pools

b. Pools stabiized with cyanuric acid

c. Un-stabilized hot tubs

d. Stabilized hot tubs

a. 1ppm

b. 2ppm

c. 3ppm

d. Trick question, not recommended for stabilized hot tubs

What pH should pools maintained for disinfectants to be maximally effective?

7.2 and 7.8

How much FAC is available as hypochlorous acid at:

a. pH 8.0

b. pH 7.5

a. 20%

b. 50%

How does chlorine become combined chlorine?

CC forms when chlorine bonds to materials in water containing nitrogen (urine, skin, sweat, etc.)

At what level in mg/l (ppm) should combined chlorine be kept to?

0.4 mg/l

What is the roll of cyanuric acid in pools?

A weak acid that acts as a chlorine stabilizer in pools exposed to UV. Reduces that amount of FAC escaping from the pool.

What is the major drawback of CYA (cyanuric acid)?

Reduces the overall effectiveness of FAC, needing more time to kill bacteria

What is the ideal concentration of CYA in a pool?

30-50ppm.

True or false: cyanuric acid is safe to use with chlorine, bromine and ozone.

False, it is not recommended to use CYA with bromine or ozone

Is bromine a primary or secondary pool disinfectant?

Primary

Bromine continually decreases ____ and ____ levels and connot be used with _____ or _______.

pH | alkalinity | CYA | ozone

What does bromine create when combined with water?

Hypobromous acid

What level of in mg/l (ppm) bromine should be present in:

a. Public swimming pools

b. Spa/hot tub/therapy pool

a. 3.0 mg/l

b. 4-6 mg/l

How do you obtain the bromine concentration of a pool using a N diethyl-p-phenylene test kit?

Multiply the chlorine reading by 2.25.

What target should UV lamps be operated at in pools?

Meet or exceed a 3-log reduction in cryptosporidium

Why must air be monitored in aquatic facilities that use Ozone as a secondary disinfectant?

Ozone is an irritant at low levels and toxic at high levels

Residual ozone concentration to remain below ____mg/l.

0.1

What target should ozone lamps be operated at in pools?

3-log inactivation of cryptosporidium

How does saltwater generation disinfection work?

Low voltage electric currents in salt water convert chloride salt ito chlorine via electrolysis

What are three reasons hand dosing disinfectant is not recommended for swimming pools?

Potential for human error, ineffective response time to chemical changes, increased worker safety risk

True or false: auto-dosing disinfectant system only need to be operational while the pool is open

False, they must be operating 24/7

What is the role of potassium monopersulfate in swimming pool maintenance?

Can be used as a oxidizing agent to “burn away” organic material, aides the primary disinfectant

What are four disadvantages of using potassium monopersulfate in a pool?

1. expensive

2. does not sanitize, only oxidizes

3. may convert chloramines into nitrates AKA algal food

4. Shows up as combined chlorine on certain tests

What does ORP stand for and what does it mean?

Oxidation-reduction potential, defined as the potential of a disinfectant to inactivate germs and oxidize organic material.

True or false: ORP and disinfection level do not have a linear relationship.

True

What is ORP measured in?

Millivolts

______mV ORP allows for quick disinfection and breakpoint chlorination when conditions permit.

650-720

What is the ideal water balance for:

a. pH

b. Alkalinity

c. Calcium hardness

d. Total dissolved solids

e. Langelier saturation index (LSI)

a. 7.2 - 7.8

b. 60 - 180ppm

c. 150 - 400ppm (pools) 100 - 250ppm (spas)

d. 1500ppm max above fill water

e. -0.3 - 0.3

What are some drawbacks of pH above recommended levels? (4)

Scale forming, shortens equipment lifespan, increases maintenance, free chlorine loses its oxidative ability.

What are some drawbacks of pH being below recommended levels?

Water is corrosive to pool equipment and surfaces, irritates eyes and skin, bathing suit wear

How often should pH levels be tested during open hours of a pool?

Once ever 2-4 hours

Name four common influences of pH in pools

1. Addition of disinfectants that are strongly acidic or basic

2. Aeration

3. pH of source water

4. Patron hygiene

What is alkalinity in pool water balance and why is it important to measure?

Alkalinity measures the amount of salts in the water, which acts as a buffer to prevent rapid fluctuations in pH. It is measures as total alkalinity of 200ppm or greater can make it difficult to adjust pH, known as pH lock

What is calcium hardness in water balance and why is it measured?

Calcium hardness measures the amount of calcium salts present in water, and it is measured because high calcium hardness can cause scaling, whereas low calcium hardness can lead to corrosion

What is the Langelier Saturation Index and how is it calculated?

The LSI measures the “balance” of the water between aggressive/corrosive (less than -0.5 for unheated water and less than -0.2 for heated water) and scale-forming (greater than 0.5). It is calculated: Saturation index = pH + water temp + (alkalinity - CYAppm if present) + calcium concentration - 12.1 (constant for TDS)

What two groups should not use hot tubs?

Children (because they can’t self regulate temperature very well), and pregnant women in their first trimester

True or false: microbiological testing is not necessary in routine pool inspections if minimum disinfectant levels are being met.

True

A swimming pool built or renovated after 2014 must have a turnover rate of ____

Every 6 hours

A swimming pool built before 2014 must have a turnover rate of ____

6 hours or 4 times in 24 hours

Define turnover rate.

The amount of time it takes for the pumping and filtration systems to cycle all of the water in the pool one time.

True or false: Increase in turnover rate means an increase in flow rate.

True

What three things may a drop in flowrate indicate?

1. Filters need to be cleaned

2. Skimmers need to be cleaned

3. There is an issue with the water pump

What issue may arise from a flow rate that is too high?

Suction entrapment hazards

What is the role of filtration in water circulation systems? (4)

To remove particles that shield m/o, cause turbidity, remove organic particles that contribute to disinfection by-product, remove Crypto oocytes and Giardia

What are 5 commonly used filter types in pool circulation systems?

1. High rate sand (5-20 gpm/ft2)

2. Diatomaceous earth (2.0 gpm/ft2

3. Rapid sand filter (3gpm/ft2)

4. Cartridge (0.375 gpm/ft2)

5. Diatomaceous earth with slurry (2.5 gpm/ft2)

When should you backwash a filter?

As per manufacturers instructions, but generally when the water entering the filter and the water exiting reaches 10-30 psi difference in pressure gauge, or if there’s only one gauge 8-10 psi increase.

Filter backwash lines, deck drains and other drain lines shall be discharged through _______.

Air gaps

Name 4 pieces of safety equipment that should be at a pool.

• Reaching pole

• Buoyant throwing aids

• emergency telephone and communication

• A.E.D

• First aid equipment

• Signage

Name 4 pieces of safety equipment for life guards.

• Communication device

• Rescue tube or equivalent

• Breathing protection for mouth-to-mouth and PPE

• Identifiers (life guard shirt, etc.)

• Sun (UV) protection

• Spine board

• Control station

• Signage

Name 6 components of an aquatic safety plan.

• Administrative info (name, addresses, management structure, staff training (on the aquatic safety plan), operation and maintenance personnel)

• Pool info (description, type, months of operation, bather load, area of pool, volume of pool, depth, flow rate, types of equipment, amenities, etc.)

• Closure policy

• Aquatic water chemistry, testing frequency and normal ranges

• Aquatic water test kit and regents

• Aquatic water chemicals adjustment

• Safe handling of chemicals

• Preventative maintenance of mechanical equipment (filters, chemical feeders, ozone, etc.)

• Task lists

• Pool cleaning schedule

• Lifeguard to patron ratio

• Lifeguard procedures and duties

• Emergency procedures

What is the target organism for a formed stool incident in the pool?

Giardia