What's in the Water? Lesson 3: The Economic Challenges of Clean Water

Jessica Merricks, Biology

Kelsey S. Bitting, Environmental Studies & Center for the Advancement of Teaching and Learning

Elon University

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Initial Publication Date: January 31, 2022


Prior to the start of the third lesson of the "What's in the Water?" PFAS Contamination Unit", students will review several primary sources to learn more about PFAS water contamination in the local context. They will reflect on the patterns presented in the data regarding the location and makeup of PFAS in the Haw River, and draw conclusions about the level of risk to local residents. In class, students will explore and discuss presentations by the private engineering firm charged with assessing potential remediation efforts at the town's municipal drinking water facility. Groups will work together to evaluate the firms' claims based on data provided in their Lesson 3 Data packet, then draft a list of questions that may help the town decide which option to choose. The lesson closes with an open discussion in which the students consider the logistical and financial challenges associated with local remediation of emerging contaminants.

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This activity has been used in an introductory-level university course in environmental science that enrolls both majors and non-majors, as well as a summer intensive science course for high school students, both in North Carolina where the unit is set. It could easily be adapted to other locations where PFAS contamination is present, as well as to geology or biology courses.

Skills and concepts that students must have mastered

Students should practice analyzing texts, figures, and datasets alone and in groups prior to engaging in this lesson.

How the activity is situated in the course

This is the third instructional lesson of the "What's in the Water?" PFAS Contamination Unit". Prior to this lesson, students will have been introduced to the unit-long community-engaged project, met the community partners to understand the local PFAS contamination situation and the community partner's needs, and completed the Benchmarking Activity to take stock of their prior knowledge of water and water contamination. In Lesson 1, they learned about the natural and urban water cycles, focusing on PFAS contamination and how it cycles through the environment. In Lesson 2, students compared and contrasted emerging and established contaminants, and learned about the PFAS family of chemicals and their history. This lesson takes students through an analysis of remediation options for the local water contamination crisis.


Content/concepts goals for this activity

  • Students will be able to analyze the costs and benefits of local efforts to treat water contamination.

Higher order thinking skills goals for this activity

  • Students will be able to critically evaluate various types of data related to water contamination and filtering techniques.

Other skills goals for this activity

  • Students will be able to take on the perspectives of multiple stakeholders, build sound arguments, and collaborate on decision making.

Description and Teaching Materials

In this lesson, students will study and evaluate several sources of data to better understand the local water contamination issue. The lesson will focus on two primary objectives:

  • What are the possible solutions for eliminating PFAS from the town's drinking water?
  • Based on the pilot remediation study, what remediation approach should the Pittsboro board choose? What trade-offs are involved in that choice?

Pre-Class Homework and/or in-class discussion
Prior to starting the lesson, students will need to understand the extent to which the residents of Pittsboro are being exposed. The purpose of this assignment is to provide an opportunity for students to view PFAS data collected by local scientists in order to decide the severity of the problem in Pittsboro. Specifically, each student will draft a brief response to the questions below.

  • What patterns do you see in the data regarding the location, concentration, and makeup of PFAS chemicals in the Haw River?
  • What do we know about the "profile" of the PFAS chemicals being detected in the Haw River? Is it similar to the types of PFAS being detected elsewhere? How might the profile help us understand the origin of the contamination?
  • Based on the data, is there cause for concern regarding the presence of PFAS in the Haw River? Why or why not?

Activity 1 (Homework Review; optional)
If students struggle with the data packet activity in the homework assignment, or you want to help them thoroughly unpack the ideas represented in the figures, it may be worth spending time at the beginning of class to debrief/unpack the sources. This structured/guided walk-through may better enable students to tackle the next phase of analysis during this lesson. This approach is reflected in the instructor slides and v.1 of the Class Plan and Timeline. Alternatively, if students are more adept at analyzing these figures on their own, time may be reserved in the class period for groups to work on their capstone projects, reflected by v.2 of the class plan and timeline.

Opening Lecture/Discussion
As context for exploring the remediation data (Small Group Activity 2 in v.1, Activity 1 in v. 2), share with students an update from a local resident who is growing more concerned, and frustrated, about the water issue in town. It's been almost a year since she received the vague note in her water bill, and she's anxious for an update. She heard about a pilot study being conducted by an engineering firm, CDM Smith, to look into the feasibility of putting in some type of filter at the drinking water facility just north of town. She notices that the Board of Commissioners has a meeting planned for the following week to hear about the results of the pilot study. She decided to attend the meeting to hear the latest updates. During the meeting, she learns that CDM Smith has been conducting a pilot study at the local water treatment facility for the past year. She tries her best to follow along, but the graphs and jargon make it difficult for her to take notes. She finds a copy of their presentation on the town's website (Sources 6 and 7 in the Lesson 3 Data Packet).

Activity 2 (Remediation Options)
Students will work in small groups to study and discuss the information from CDM Smith's presentation to Pittsboro's Board of Commissioners (Sources 6 and 7). Several tradeoffs must be addressed, including, cost, effectiveness, waste, infrastructure limitations, and energy use. Groups should work towards two goals: (1) evaluate CDM's claims based on earlier data and data from other sources in the Data packet. (2) draft a list of questions that would help the town decide which option to choose.

Groups do not have to produce a physical deliverable for this activity. Depending on the number of groups and the level of engagement, students could compile their thoughts on a shared doc/slide and/or share orally once everyone is ready.

Once everyone is ready, have groups share their thoughts. Ask them to compare and contrast data from multiple sources to evaluate the results of the pilot study. Are the treatment options effective? Are there any perceivable issues (does the treatment effectively address the specific PFAS profile in Pittsboro, can it reduce the amount of PFAS to an acceptable limit (e.g. 70 ppts), Do we agree with CDM Smith's recommendations, Why or why not, etc.). This is a great opportunity to bring in questions about environmental justice. How might the town's decision disproportionately impact marginalized populations?

Synthesis/Reflection Questions
The purpose of the closing discussion is to help students recognize the various views of stakeholders involved and the logistic and financial challenges associated with local remediation of emerging contaminants. The following questions and discussion prompts may be helpful as you conclude the lesson.

  • In your opinion, what are the primary responsibilities of Pittsboro's Mayor and Board of Commissioners pertaining to the water issue?
  • Do you feel the treatment options are sufficient? Why or why not? Is it possible to completely avoid contamination?
  • POV Statements: Write a statement from the point of view of a Pittsboro resident based on what you know so far. You could write a reflection expressing your feelings about the water issue (what bothers you the most), your concerns about yourself and others in the community, or something else. In your opinion, what should happen next?

Lesson 3 Class Plan and Timeline (Microsoft Word 2007 (.docx) 9kB Jan26 22) 
Lesson 3 Pre-class Homework Instructions (Microsoft Word 2007 (.docx) 8kB Jan26 22) 
Lesson 3 Background Guide for Instructors (Acrobat (PDF) 159kB Jan26 22) 
Lesson 3 Instructor Slides (PowerPoint 2007 (.pptx) 3.7MB Jan26 22) 
Lesson 3 Data Packet (Acrobat (PDF) 3.6MB Jan26 22)

Teaching Notes and Tips

Depending on the course level and prior class activities, students may be apprehensive or feel ill-equipped to understand the data presented in the Data Packet, or may only analyze the figures at a very surface level. It may be helpful to review the basics of reading graphs, identifying the independent and dependent variables of an experiment, and other basic skills needed to read and understand scientific figures. This could be also assigned as an optional homework assignment in which students are asked to explain one of the figures in more depth, allowing students an opportunity to practice their skills prior to asking them to draw sound conclusions from the data.

During the activity on remediation options, instructors should encourage students to think critically as they evaluate the information from CDM Smith, recognizing that the data and information are being presented by a private company being paid to consult the town. Encourage students to think about the potential for bias in the language, selection of data, etc. presented in the CDM Smith reports.

The instructor should help students focus on the tradeoffs as they work their way through the remediation pilot study data. Several topics related to environmental justice become relevant here. For example, more expensive options may be more effective at removing PFAS, but could result in higher water bills for residents. Without grants or other assistance, the town may have no choice but to pass the cost down to water consumers. A cheaper option may mean inequities in terms of water quality, as higher-income residents may opt to further treat their homes with RO or other filters, leaving those without such resources without additional options. Such discrepancies could disproportionately impact already marginalized populations (people of color and low income communities), who are already more likely to be subjected to Safe Drinking Water Act (SDWA) violations (see "Watered Down" report, which students will explore in Lesson 4).


There are no formal assessments associated with this lesson. The instructor is encouraged to ask questions to individuals and groups as they share their thoughts from the discussion and activity. At this stage in the unit, students should be drawing connections between the content across lessons. Ideally, students will continue to develop a nuanced understanding of the problem and be able to reflect upon these new perspectives on their Benchmarking Activity at the end of the unit. If formal grading strategies are used in the course, the Benchmarking Activity could be used for summative assessment purposes.

References and Resources