The following section outlines some sample activities that can be used in the classroom in order to facilitate learning. This section provides a brief overview of some of the possible activity and some strategies for helping students progress through the content. Several of these labs can be run through kits. Kit names are listed below along with an item number and company, current as of 2017.
Nutrient Inputs and Outputs
Many of the inorganic pollutants that were mentioned previously enter the watershed from several different sources. Understanding the sources for each of these nutrients is important because learning how to limit their access to the watershed will ultimately help to reduce human exposure.
It is recommended that an initial cycle is modeled before having students look on their own. Mercury is a good example of a nutrient cycle that can be used to demonstrate how to set up a cycle as it contains both natural and anthropogenic sources. In an early cycle, teachers may want to include a list of terms to be used or a picture that has already been generated. Students can add arrows and numbers to represent the budget of that particular cycle. As students become familiar with this cycle, teachers can have student generate their own pictures showing the nutrient cycle. An extension for this activity is to have students look at different types of watersheds and compare inputs between them. For example, although nitrogen inputs may be very similar between agricultural and urban settings, the sources for these inputs may vary.
Testing Water for Pollutants
This section will outline testing procedures for both inorganic and organic contaminants. Students can obtain water from their tap, local rivers and streams, or lakes. It is recommended that students do not collect alone if they are obtaining water from outdoor sources for safety reasons. Students should also not collect samples from the surface of lakes and streams but rather from deeper in the water column for a better reading.
Once students have collected their water samples, they can be tested for a variety of chemicals. LabAids Kit #19: Qualitative Introduction to Water Pollution contains an entire array of possible pollutants that students can test their own water for. Once students have finished profiling their water sample, students can compare samples to one another.
An extension for this lab is to have a field trip where samples are collected along the length of a watershed. Samples can be refrigerated in a bag with ice to keep them until testing can occur at the lab. Students should mark the location along the watershed where they collected theses samples. After testing the samples, students can create a ‘profile card’ along the watershed, noting pollutants of interest. This map can be expanded further to have students look at adjacent lands and figure out what possible inputs of pollution might stem from.
Impact of Pollutants on Human Health
Only a small portion of the possible contaminants found in a watershed are listed above. Once students have tested their water, the next logical step is to look at the effects of these pollutants in the water source. If it is suspected that all water shed samples will read within allowed tolerances, the impacts of these chemicals can be assigned before testing.
Students should look for the common inputs of this source of pollution, both natural and anthropogenic, in addition to their short term and long term impacts on the major body systems and how to treat this On a large drawing of a human, students can color code the organs and tissues affected by these organs and list their long term effects. The collection of these posters can be displayed in a hallway or can be scanned and shrunk down to create a classroom set of notes.
Case Files Lessons
All of the examples of chemical and biological pollutants can be presented to students in a variety of case-study formats. I have presented several casefile formats that can be altered with any of the types of cases.
Case Study Format A—Traditional Case File
A traditional casefile would be excellent for pollutants like mercury, nitrates, or even some of the biological contaminant like
N. fowleri
. In a traditional case file, patients come in complaining of initial symptoms. Casefiles should include important patient history in addition to their blood temperature, respiration rates, blood pressure, and other important intake information.
Students should begin by reading through the patient file and text coding. A recommended method for reading through the casefile is as follows. Initially have students read the file and box any terms that they do not understand. Students can then take time to look up those words to create a class vocabulary list for the patient. This is an excellent opportunity to introduce medical terminology and help students learn prefixes and roots that are commonly used in medicine.
Once students have completed this initial read through, they should complete a second pass through where they underline any symptoms that the patient is experiencing. These symptoms can be listed on small white boards as a group assignment or on the class white board if the case file is being worked through as an entire class. Students can then begin the third and final reading where they identify any other important information about the patient that can be helpful in identifying what is wrong with their patient. In all of these samples, I would recommend that particular emphasis is given to locations that the patient may have been before becoming ill.
Students can then brainstorm illnesses that could be causing the symptoms. If students have participated in other medical classes before this unit, students may have background knowledge in the effects of some of these nutrients on the body already and may not need to use the internet. Otherwise, students can use reliable source to identify the cause of the illness. Students should always complete a written analysis of the symptoms that their patient has presented with and how those symptoms are directly tied in with the suspected illness. Furthermore, since many illnesses may present with similar symptoms, it is crucial that students identify alternative diagnoses and justify their decision to dismiss them.
An alternative method for presenting an individual casefile to either make it more interesting and challenging for students is to have an initial casefile where the patient is admitted to the hospital with some of the initial symptoms. The patient’s stats can change in ‘real time’ and crises can be included after certain periods of time. For example, for someone suffering from
N. fowleri
infection, neurological symptoms and coma can easily be introduced as ‘updates’ to the initial case file. Using this format, teachers can create a sense of urgency as their patient becomes sicker and sicker. In some case files, it might be interesting to have the patient pass and provide the final update in the format of an autopsy report for students to analyze.
Case Study Format B—Epidemiological Case File
Similarly to the presentation of a single case file as outlined in format a, there is also an opportunity for multiple casefiles to be introduced at a single time in the form of an epidemiological outbreak. This format might work especially well for instance of coliform,
Crypto
, or even lead. Individual casefiles can be presented, one to each group, and students can each create a map for their patient and draw connections if the casefile will be addressed as a full class. Or, if students are working in individual groups, each group can receive all of the casefiles and create their own concept map of the infection.
In an epidemiological case file, not all patients need to present with the same symptoms, at the same time, or even with the same severity. Cases can be complicated by including patients with similar presenting illnesses that do not fit in with the profile or by presenting updates to patients based on clinical testing.
Case Study Format C—Timelines and Trials
The creation of timelines are best served for complex examples that might benefit from students having prior knowledge about a case and how the particular pathogen works. For example, this type of casefile is strongly recommended for the Washington lead case file, the Bangladesh arsenic case file, and the outbreaks of cryptosporidium. While all three of these casefiles can be presented in the traditional or epidemiological file, doing so will strip them of the important ethical situations that make these cases so intriguing.
In all of these cases, student can be presented with small bits of information at a time. For example, in the lead casefile, students can start looking at the research being conducted in 2001 and progress through the case by receiving primary and secondary articles, tracing the testing, concealment, and eventually public exposure of the incident and into the remediation. Students can do embedded tasks, including testing water for lead and mapping the location of the most severe contamination.
A similar progression can be done with the arsenic case file, where students look at some of the surface water results and propose solutions. Students can be introduced to the concept of drilling wells as part of the remediation effort, and then look at the introduction of casefiles resulting for acute arsenic poisoning and end with remediation efforts.
After students have finished looking at the background of these cases, a further extension might include students having a mock trial where they take on the roles of various parties involved and conduct a trial to determine fault and damages to be paid out by those affected. This can also be presented as a debate, again with students taking on various roles within each of these casefiles.
