Problem-based-learning (PBL) techniques have become increasingly popular in many health-related fields (Albanese, 2001; McGrath, 2002; Gofin, 2002; Green, van Gyn, Moehir, Lau, & Coward, 2003; Kanter, 1998; Mok, Lee, & Wong, 2002; Stromso, Grottum, & Licke, 2004) and are particularly important in training environmental health professionals (Nieboer, 2002). PBL is premised on the self-directed acquisition of knowledge in a setting that requires the learner to restructure information in a realistic context. Students are then asked to elaborate on this new knowledge through interactions with peers (by teaching or discussion) (Kilroy, 2004). The key characteristics of PBL, as described by Kanter (1998), are as follows:
(1) the primary learning activity is problem solving rather than memorization; (2) the student is an active rather than a passive participant; (3) the teacher functions as a facilitator rather than an instructor; (4) the environment is one of collaborative, group- centered learning rather than competitive, individual-centered learning; and (5) the problem is ill-structured rather than well- structured. (p. 391) Kanter's definition of an ill-structured problem involves two factors: 1) little information is initially presented (which increases the level of uncertainty of the learner), and 2) the solution to the problem is not obvious (Kanter, 1998).
Excellent subject matter for PBL exercises can be gleaned from several highly publicized legal disputes involving human illnesses ostensibly resulting from exposure to contaminated environments (so-called "toxic torts"). Although there are many such cases to choose from, the issue of aquifer contamination in Woburn, Massachusetts, and, to a somewhat lesser extent (because there was an arbitration settlement), the case of groundwater contamination in Hinckley, California, are particularly well suited for these exercises given most students' familiarity with their content through media accounts, novels, and major motion pictures. These conflicts are inordinately complex and ill structured, and require significant expertise in disparate fields, including human environmental medicine, oncology, toxicology, epidemiology, hydrology, law, sociology, and other disciplines. Most environmental health and legal professionals would agree that proving causality in such cases is very difficult (Robbins, 2003) and, in many cases, nearly impossible. Given this premise, students were asked to address questions such as: "Just how important is it that we reach absolute conclusions on causality, blame, or liability?" and "Do you agree that once these matters reach the legal system, that the truth can be found only at the bottom of a bottomless pit?"
When environmental contamination is at issue, many questions often remain unanswered--questions about the nature and extent of the contamination, source, duration, human exposure levels, and genetic susceptibility. In addition, it is difficult to assess the risks and consequences of exposure to mixtures of contaminants for human health and the environment. It is no wonder that attempts to resolve the myriad of intertwined issues through the judicial system can drag on for more than a decade, often to the dissatisfaction of all parties (stakeholders). The highly contentious nature of the conflicts that emerge once a serious environmental contamination has been identified can stir powerful emotions, including outrage, anger, fear, and frustration, among those who have seen valuable natural resources sullied and human health potentially compromised. Unfortunately, these emotions, although understandable and often well justified, provide a poor landscape for rational decision making. This problem is compounded by the fact that the populations most affected by the contamination often have neither the technical understanding, the political clout, nor the legal savvy to address the problem.
Environmental health professionals are well equipped to deal with such situations by virtue of their broad, multidisciplinary training, although even the best-trained professionals can find these situations difficult. To better prepare environmental health professionals for such challenges, instructors may find that a problem-based-learning approach has considerable value, especially when critical-thinking skills are employed (Jones, 2002; Paul, 1995; Paul & Elder, 2001; van Gelder, 2001). Critical-thinking courses are often taught in English or philosophy curricula, and introduce students to recognized approaches for constructing well-supported arguments. Unfortunately, these courses tend to be taught early in an undergraduate career and are rarely reinforced in upper-level course work or within the context of a major discipline. An ideal environment for applying these principles is afforded by case studies involving complex environmental issues.
A Civil Action, a work of nonfiction by Jonathan Harr (1996), chronicles the events surrounding the contamination of the aquifer that supplied well-fields for town production wells G and H in the heavily industrialized community of Woburn, Massachusetts, just north of Boston. A class-action lawsuit was filed on behalf of several families who alleged that drinking water drawn from the contaminated wells resulted in illness and death within the community. The defendants of the lawsuit included two "deep-pocket" multinational corporations that were alleged to have contributed varying amounts of chlorinated...