Case Study – Elemental Mercury Spill

FACILITATOR VERSION

Objectives

·  Given a case definition and a description of a possible case, select the appropriate case classification.

·  List effective interview techniques

·  Describe specimen collection procedures for a given outbreak situation.

·  Identify critical public health messages for a disease or condition.

Instructions

Convene your local Epi Team, and provide each Epi Team member with a copy of the case study (participant version). Choose one person to act as the facilitator. This person should use the facilitator’s version of the case study.

Guidance for facilitating the case study can be found on the next page. The case study begins on page 3.

Time Allotted: 1.0 hours

Background Materials

The following training, found at the North Carolina Center for Public Health Preparedness Web Site (http://nccphp.sph.unc.edu/training/), is recommended for Epi Team members without prior outbreak investigation experience. It can be viewed prior to completing the case study.

  1. Interviewing Techniques (I is for Investigation, Session 4)

Resources

U.S. Environmental Protection Agency. Mercury spills, disposal, and site cleanup. Environmental Protection Agency. http://www.epa.gov/hg/spills/index.htm. Updated February 29, 2008. Accessed March 7, 2008.

U.S. Environmental Protection Agency Region 5. Mercury response guidebook (for emergency responders). Attachment B: Guidelines for responding to mercury spills and releases in schools and residences. 2004. http://www.epa.gov/hg/spills/index.htm#guidebook. Published July 2004. Accessed January 16, 2008.

North Carolina Center for Public Health Preparedness. Interviewing Techniques. FOCUS on Field Epidemiology [serial online] 2(3). http://nccphp.sph.unc.edu/focus/vol2/issue3/. Accessed February 6, 2008.


Guidance for Facilitators

Goal

The goal of working through a case study is active learning through engaged participation by each Epi Team member.

Role of Facilitator

As a facilitator, your job is to:

·  Guide the Epi Team through the case study

·  Involve every team member

·  Moderate discussion drawing on the suggested answers to discussion questions

·  Ensure key points are covered for each question

·  Keep an eye on the clock

Active Participation

All team members should be involved in the discussion. One strategy for getting everyone involved is to have team members take turns reading aloud and attempting to answer questions. Facilitators should:

  1. Ensure that the room set-up encourages group participation, ie. everyone seated around a table or chairs in a circle.
  2. Select one team member to read aloud the first update and the first question.
  3. Encourage that team member to attempt to answer the first question (regardless of his/her background).
  4. Encourage other team members to add information and discuss the question.
  5. Use the suggested answers to cover key point(s) that were not addressed during the discussion.
  6. Have the next person read aloud the next update or question and begin an attempted answer as above – move in sequence to include everyone.

Follow this sequence until the scenario is completed, pacing discussion in order to finish the entire scenario.

Facilitation Tips

·  Read the case study ahead of time so you are prepared for the discussion.

·  Always remember the learning objectives for the case study.

·  If one person is dominating the conversation, call on other team members.

·  If someone in the group is not participating, ask his or her opinion.

·  When someone asks a question, encourage other team members to provide the answer.

·  Do not spend too much time providing the suggested answers to the group. Instead, encourage the team to share their opinions about possible responses to the given scenario.

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Question 1: What advice should you give the principal?

Suggested answer: Inform the principal that the health department will lead the clean-up and decontamination effort. In the meantime, the school can initiate some simple precautions, such as:

·  Keep people out of the area, and do not let them walk through the spilled mercury on their way out of the room;

·  Ventilate the area by opening windows, but shut all doors to other parts of the building;

·  Do not vacuum or sweep the mercury;

·  Do not pour mercury down the drain;

·  Do not wash mercury-contaminated items in the washing machine;

·  Do not walk around if your shoes may be contaminated with mercury; and

·  Do not allow children to help clean up the spill.

For some smaller spills, the EPA recommends that schools or homeowners can clean up the mercury using a proper clean-up kit. In this situation, you should recommend that the school wait until health or emergency officials have arrived.

You may also want to provide the principal with guidance about a letter to parents explaining the situation and the health risks of mercury exposure. Before the health department arrives, the principal should get a list of students who may have been exposed to the mercury.

Question 2: Who else should you notify about the mercury spill?

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Suggested answer: You should notify the county Emergency Management agency to decontaminate the area. Emergency Management may request additional assistance from the North Carolina HazMat Regional Response Team if the spill is large and local resources are limited. You may also contact the NC Division of Public Health Occupational and Environmental Epidemiology Branch to assist you with a health and environmental assessment. Another good resource is your Public Health Regional Surveillance Team, or PHRST. The PHRST team is often able to provide guidance and surge capacity for public health emergencies.

The school may want to notify its public information officer, who can prepare information for students and parents.

Question 3: Would your health department activate its Incident Command System (ICS) in this situation?

Suggested answer: Depending on the size of the mercury spill, activating the ICS structure within the health department or a Unified Command in collaboration with local Emergency Management may be appropriate at this time. For a small spill, the health department may use ICS with a limited number of positions.

Question 4: What is the role of the health department in this type of mercury spill?

Suggested answer: According to the Environmental Protection Agency, the role of the public health agency is to “determine (1) if potentially exposed individuals should be referred for clinical assessment, and (2) if biological testing should be conducted. The public health agency can also interpret results and notify residents of biological and medical testing. Furthermore, the public health agency will decide if relocation is needed and when clean-up levels have been achieved. The health agency may also conduct health education and outreach.”[1]

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Group Brainstorm

Choose one team member to record answers on a flip chart. As a group, brainstorm about potential questions that might be included in an interview questionnaire for students and staff who may have been exposed to mercury. Out of all of the questions generated, identify the 5 most important to include in the questionnaire.

Suggested answer: Types of questions that may be included are: demographics, pregnancy status (for females), proximity to mercury spill, specific type of exposure (e.g. touching mercury droplets, trying to burn the mercury, ingesting mercury, etc), any attempts to clean mercury (especially sweeping or vacuuming) or take it somewhere else, approximate duration of exposure (i.e. length of time in the room following the spill), and symptoms consistent with mercury exposure (e.g. burning eyes).

Role Play

Facilitator: A Student Information Handout is included at the end of the case study and should be given to participants acting as the student in the role play activity.

Choose one of the following options to simulate the interview process, using the 5 questions you have just generated.

Option A

One Epi Team member will play the student who broke the thermometer and another team member will act as the interviewer. The pair will act out the interview while the rest of the Epi Team observes. The team member playing the student should use the Student Information Handout available in the facilitator version of the case study.

Option B

The Epi Team should divide into pairs, and each pair should conduct the interview, with one team member acting as the student and one as the interviewer. The team members playing the student should use the Student Information Handout available in the facilitator version of the case study.

After the role play, discuss the next question as a team.


Question 5: What techniques did the interviewer use that were effective?

Suggested answer: There are many techniques used by skilled interviewers. A few important ones are:

·  Be neutral, yet attentive. Face the participant at a comfortable distance and maintain appropriate eye contact.

·  Be accepting of the participant. Do not express any judgment of the participant through your body language, tone, or facial expression.

·  Concentrate on what the participant is saying. Do not let your mind wander or interrupt the participant.

·  When necessary, prompt for clarification and probe beyond “I do not know.” Use silence first; then repeat the question. If necessary, use a neutral probing statement.

o  For open-ended questions, probes such as “Could you tell me more about that?” or “How did you feel about that?” might be appropriate.

o  For closed-ended questions, repeating the question or offering dates, times of day, or seasonal holidays might help a respondent remember.

A few techniques that might be especially relevant in this situation are skills establishing rapport with teenagers, assuring the students that they are not in trouble, and providing education at the conclusion of the interview.

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Question 6: Do the observed levels of mercury in the air samples indicate the need for decontamination?

Suggested answer: Yes. The Agency for Toxic Substances and Disease Registry (ATSDR) publishes Suggested Action Levels for Indoor Mercury Vapors, which can be found at http://www.ert.org/products/mercury_response_guide/AttachmentE.pdf. These guidelines recommend decontamination of areas with mercury levels above 3000 ng/m3. Based on the air sample results, at least the sink and both areas of the floor should be properly decontaminated.

Question 7: Should clinical specimens be collected from any students?

Suggested answer: At this point, you do not know the full extent of mercury exposure for the students. Because high concentrations of mercury were detected in air samples, it may be appropriate to consider healthcare referral for the students with the most exposure. Specimens may be collected to determine the extent of exposure. Local health departments may contact the North Carolina Occupational and Environmental Epidemiology Branch for guidance specific to the situation.

If you answered yes:

Question 7a: What type(s) of specimens should be collected?

Suggested answer: Blood and urine specimens are used to test for mercury exposure.

Question 7b: Who is responsible for collecting the specimens?

Suggested answer: The specimens would typically be collected by a healthcare provider.

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Question 7c: Where should specimen samples be sent?

Suggested answer: Specimens should be sent to the North Carolina State Laboratory of Public Health or a reference laboratory.

If you answered no:

Question 7d: Why is it not appropriate to collect specimens at this time?

Suggested answer: Recent recommendations for out-of-hospital management of people exposed to mercury are to “consider healthcare referral for those exposed to documented high air mercury concentrations.”[2] Based on this recommendation, it would be possible to wait until the students have been evaluated by a healthcare provider before deciding whether it is appropriate to collect specimens. Another reason not to collect specimens is a lack of effective therapeutic approaches for persons with low levels of mercury exposure.

Activity

As a group, write three (3) key messages to include in a statement to the media. Keep in mind that your goal is to emphasize the danger of inhaling elemental mercury as well as to provide basic information about mercury spill clean-up. For ideas, you can refer to:

·  Appendix A: U.S Environmental Protection Agency. Spills, Disposal, and Site Clean-up. http://www.epa.gov/hg/spills/index.htm. Accessed April 15, 2008.

·  Appendix B: Agency for Toxic Substances and Disease Registry. Mercury. 1999. http://www.atsdr.cdc.gov/tfacts46.pdf. Accessed January 23, 2008.

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Suggested answer: Your statement to the media should include an update about the situation at the school, as well as educational information about mercury.

First, emphasize that the exposure at the school was brief and it is highly unlikely that anyone will have health effects, and the health department is monitoring the situation to ensure proper clean-up.

There are many possible messages about mercury that may be shared in public information materials, including the following:

·  What is mercury? Mercury is a naturally occurring metal, which is a shiny, silver-white, odorless liquid at room temperature.

·  Where is mercury found? Mercury is found in some dental fillings and medical equipment, fluorescent lightbulbs, some thermometers, and can also be an environmental contaminant.

·  How could I be exposed to mercury? The most dangerous exposure is by breathing air contaminated with mercury. Since mercury is an odorless gas, it is impossible to know whether you are breathing contaminated air. Exposure can also occur by handling or ingesting mercury.

·  What happens if I am exposed to mercury? Exposure to metallic mercury can cause lung damage, nausea, vomiting, diarrhea, skin rashes, eye irritation, and increased blood pressure and heart rate. Chronic exposure, such as through ingestion of contaminated fish, can cause birth defects and neurological damage, especially in children. If you have been exposed to mercury, see a healthcare provider.

·  What should I do if I spill liquid mercury? Keep children and other people away from the spill. Do not vacuum or sweep the mercury. Call your local health department for guidance about proper clean-up.

Activity

Based on the information above and the CDC Case Definition for Inorganic Mercury Poisoning (http://www.bt.cdc.gov/agent/mercury/mercinorgcasedef.asp) below, classify each of the four students as Suspect, Probable, or Confirmed Cases. Students who do not meet the case definition based on laboratory results may be classified as “Not a Case.”