Practice Questions

Are you a student or a practitioner who wants to keep up your problem-solving skills?  We have put together a number of scenarios on various environmental health topics.  Each scenario is followed by a set of questions for you to consider.  The scenarios in the first list below include answers; the ones in the second list do not.

Q & A's
Nematodes for pest control^NEW!
Pool chlorination and closure guidelines
Carbon dioxide in indoor air
Pepper spray in the indoor environment
PBDEs

Q's
Smoke infiltration in a rural hospital
Lead in school drinking water
Mercury in corn syrup
Water treatment
Well contamination
Active transportation
Power lines
Backyard chickens
Bed bugs
Carbon monoxide
Food safety and security
Listeria
Mould
Water fluoridation
Wind turbines
Contaminated soil 

Please let us know if you have scenarios and/or questions you’d like to share.

Smoke Infiltration in a Rural Hospital 

1. What are the benefits and risks of turning off an HVAC system in a hospital?
2. Describe two other options for protecting patients.
3. What health concerns are associated with forest fire smoke exposure?
   1. Who is most affected?
   2. What pollutants in indoor air would be a concern?
4. The smoke intensifies and you have the resources to evacuate a small number of patients. What ethical considerations would be important in making the decision of whom to evacuate? 

Lead in School Drinking Water

1. What is your initial approach to this issue?
   1. What additional information do you need?
2. What are the health concerns of lead exposure to children?
   1. What are the levels of exposure associated with health concerns?
3. How is the Health Canada Drinking Water Guideline for Lead derived?
4. Which factors influence lead levels in water?
5. What strategies would you use to address elevated lead levels in school drinking water?
6. Interpret the figure below (taken from Lanphear et al. 2005):

Suggested resources:
Barn P, Kosatsky T. Lead in school drinking water: Canada can and should address this important ongoing exposure source. Can J Public Health. 2010: 102(2): 118-21.
Health Canada. Lead. Ottawa, ON: Health Canada; 1992.
Lanphear BP, Hornung R, Khoury J, Yolton K, Baghurst P, Bellinger DC, et al. Low-level environmental lead exposure and children’s intellectual function: An international pooled analysis. Environ Health Perspect 2005;113(7):894-99.
US Environmental Protection Agency. 3Ts for Reducing Lead in Drinking Water in Schools. Washington, DC: EPA; 2006.

Mercury in High-fructose Corn Syrup

You are a physician working at the BC Centre for Disease Control. Media reports have come out warning of mercury contamination in common food products containing high-fructose corn syrup. You have been contacted by several Medical Health Officers who are receiving calls from worried parents; they are asking about the risk to their children’s health and wondering what will be done to protect them.

Questions to consider:

1. What form of mercury has been found in the foods?
2. Is the form and amount of mercury cause for concern regarding health risks?
3. What questions still need to be answered?
4. How would you reply to the growing public outrage?

Suggested resources:
Dufault R, LeBlanc B, Schnoll R, Cornett C, Schweitzer L, Wallinga D, et al. Mercury from chlor-alkali plants: measured concentrations in food product sugar. Environ Health. 2009;8(1):2.
Rideout K, Sahni V, Copes R, Wylie M, Kosatsky T. Comment on the paper by Dufault et al.: Mercury in foods containing high-fructose corn syrup in Canada (letter to the editors). Environ Health. 2010;online comments (July 21).

Water Treatment

A small city in Northern Alberta is planning a new water treatment facility.  The facility manager asks the regional MOH to assist in determining which water quality parameters should be used to assure microbial safety of the treated water.

Questions to consider:

1. As MOH, what would you want to know about the water source, the treatment facility, the distribution system, and the population served before offering an opinion?
2. What are the characteristics of an ideal indicator of microbial water quality?
3. Name two water treatment options.  What are the advantages and disadvantages of each?  How might the choice of treatment option influence your recommendation on water quality parameters?

Well Contamination

This morning, police reported the vandalism sometime during the night before of two community wells in a central Vancouver Island town recently beset by civil unrest related to clear cut logging. 

The wells are the sole water source for the town of 20,000.  The nearest population centre (and alternate water source) is 40 km away. 

According to police, well covers were tampered with and left open. Investigating authorities found no visible evidence that foreign material had entered the wells.  “A painful death to the bourgeoisie” was painted on both pump houses. 

The city manager turned off the pumps immediately after being notified of the situation.  No relevant illness has been reported.

Questions to consider:

1. As regional MOH, what do you do? 
2. Who do you work with? 
3. What contaminants should you be concerned about? 
4. What can/should you test for? 
5. What do you advise about provision of water now? 

Active Transportation

You are an MHO of an urban health authority in a city with ongoing air quality issues.  You are approached by your CEO to develop a program to address active transportation.

Questions to consider:

1. What is active transportation?
2. What are some of the health benefits and risks associated with active transportation?
3. What approach would you take to develop a program aimed at active transportation?
4. How would you evaluate the program?

Power Lines

A municipality of 100,000 people is upgrading local high voltage power lines near a school.  The superintendant has called you, the MHO, as the School Health Officer, to meet with Mothers Against Power Lines advocacy group at the school. 

This is a role play.

Thank you for joining us.  I am Mrs. Shepke, director of Mothers Against Power Lines, and beside me is Mrs. Templeton, school principal.

1. What are the risks associated with high voltage power lines?
     a.  How do you determine whether the power lines cause health effects?
2. How would you evaluate the risk in this situation?
3. I have read about the precautionary principle.  Since children are at risk from these lines, shouldn`t we be using the precautionary principle? 
4. How can we work together to address my concerns?
   

Backyard Chickens

As the local Medical Health Officer, City Council has asked for your advice on a proposal to permit households to keep chickens in their backyards. The city has a mix of urban and suburban neighbourhoods, some densely populated.

Questions to consider:

1. What infectious hazards might be associated with keeping chickens in urban backyards?
2. What are other potential public health hazards?
3. How might these hazards be mitigated?
4. What are potential benefits to raising backyard chickens?
5. How would you present your argument to Council, so that they weigh both health risks and benefits in their decision?

Bed Bugs

You are a Medical Health Officer in Vancouver. Recently, there have been reports of bed bug infestations in local hotels. With the upcoming Olympics, hotel owners are concerned about the impact of these reports on their businesses.

CBC radio has asked for an interview on their morning show.

Suggested role play:

CBC Radio:

"Good morning Dr._____. Thanks for agreeing to come on our show. We’re hearing many reports from local hotel owners about bed bug infestations. There are real concerns out there that this might impact business during the Olympics. Why are we seeing more bed bugs?"

"Should the public be concerned about the health effects of bed bugs? Why or why not?"

"How can hotel owners prevent and control bed bug infestations?"

"Where should the public go for more information about how to check for and prevent the spread of bed bugs?"

Carbon Monoxide

You are a Medical Health Officer in an urban health authority. There is interest in setting up a province-wide carbon monoxide (CO) surveillance system and you have taken the lead on this.

Questions to consider:

1. What are the principal sources of CO exposure?
2. What are the acute and chronic health effects of CO exposure?
3. What would be the key objectives of a surveillance system for CO?
4. What would be potential sources of data? What would each source tell you and what would be the limitations?
5. How would you assess the degree to which the proposed data sources capture all cases of serious CO exposure in the province?

Food Safety and Security

You are a Medical Health Officer in a rural health authority. A local meat processing plant has proposed the donation of inventory, approaching its expiry date, to a food bank. There is disagreement, regarding this issue, between the Food Safety Officer responsible and food bank employees. The Food Safety Officer has asked for your guidance to resolve the disagreement.

Questions to consider:

1. What food security and food safety issues are related to this scenario?
2. What position(s) might food security and food safety groups take on this issue?
3. What position would you take?

Listeria

A case of listeriosis from an urban resident has been identified by the provincial lab.

Questions to consider:

1. What is listeriosis?
2. Who is at risk of exposure?
3. What groups of people are at increased risk of becoming infected if exposed to Listeria monocytogenes (LM)?
4. Which actors would be involved in this scenario? What roles would they play?
5. If the source of exposure to LM was traced to a local producer of cold-smoked salmon, what factors are important in the decision to implement a food recall? What types of food recalls exist? What is the process for implementing a food recall?

Mould

You are a physician working at the BC Centre for Disease Control. An Environmental Health Officer from a local health authority has contacted you regarding mould found near leaky pipes in a classroom. Some irate parents have refused to send their children to school, claiming that it is an unsafe environment for their children.

Questions to consider:

1. What are the potential health effects of mould?
2. From which factors would individuals experience health effects from mould?
3. Why is it difficult to establish “safe” levels of mould exposure?
4. What should be done in this situation?
5. For future prevention, what would you recommend to school officials?

Suggested resource: Health Effects from Mould Exposure in Indoor Environments

Water Fluoridation

You are the local Medical Health Officer responsible for two communities that share a common fluoridated water supply. The mayors of these communities do not agree on water fluoridation: one supports it, and one does not. The mayors have requested a meeting with you to discuss this issue.

Questions to consider:

1. As a Medical Health Officer, what is your role in this debate?
2. What are the risks and benefits of water fluoridation?
3. Other than artificially-fluoridated drinking water, what are important sources of fluoride in the environment?
4. What is Health Canada’s position on this?
5. The mayors have asked for your advice on this issue. What is your approach and what recommendations would you make?

Wind Turbines

You are a Medical Health Officer situated in a town of 50,000 people. You receive a letter of concern from a local citizen’s group, about a wind farm that has recently been situated near the town. The group claims that many residents in the town are complaining about lack of sleep and headaches associated with the wind turbines. The citizen’s group wants you to support their efforts to have the wind farm shut down.

Questions to consider:

1. What is your role as Medical Health Officer?
2. What is your approach to this situation?
3. What are the potential health effects from wind turbines?
4. Who else should you involve in this process and/or talk to for more information?
5. What recommendations would you make and who will make the final decision about this situation?

Suggested resource: Wind Turbines and Health

Contaminated Soil

A local municipality has asked their local health department for assistance in remediating roadsides, in a residential area, from which creosote-treated wooden telephone poles have been removed. Soil from around the poles was tested for phenols, monoaromatic hydrocarbons, volatile petroleum hydrocarbons, and PAHs. Selected PAH results are provided below.

  Questions to consider:

1. How would you respond to the municipality?
2. Are the existing criteria cited applicable?
3. Can you suggest alternate contaminant in soil criteria?
4. Would you suggest an alternative risk assessment/management approach?