Question 1: Formulating the problem. An abandoned underground storage tank from an old gasoline station has been detected in a community. Chemical compounds have been found to be leaking from this tank, which is near the water table providing the community its well water. Concerned about health effects of several of the chemicals in their water, the community has contracted you to risk assessment.
In one sentence, how would you define the problem? At the outset, you are charged with convening stakeholders to guide the process. Who might the key stakeholders be, and how might they contribute to your strategy for planning and carrying out the risk assessment? What types of policy alternatives might be considered?
Question 2: Identifying the hazard. The well water of the community has been tested in residences near the leaking gasoline tank, and several compounds with potential human health effects have been found. What kinds of sources of information would you examine to carry out hazard identification for your risk assessment and to address community health concerns? One compound in particular is detected for which there is incomplete toxicological and epidemiological information about health effects at low-level chronic exposures. What might you recommend in this case where data are unavailable?
Question 3: Assessing dose-response relationships. The major concern of community members about the gasoline tank leak is the increase in long-term cancer risk due to one compound present in the well water that has been linked to blood and lung cancers. This compound is thought to lead to respiratory effects as well. What would likely be the differences in your approach to dose-response assessment for the carcinogenic effect of this compound on the one hand and its noncarcinogenic (respiratory) effect on the other?
Q4. Assessing exposure. Residential well water in the community is used for everything from drinking to cooking, and from bathing to crop irrigation. What are five major exposure pathways about which you as a risk assessor, as well as local health officials and community leaders, should be concerned? What are the defaults that you might use in estimating population exposures by air and drinking water?
What are some of the drawbacks and what are some of the advantages of using each of these defaults?
Question 5: Characterizing the risk. You are nearing the completion of your risk assessment, and have found that for the compound of highest concern, the margin of exposure for respiratory effects is 5, based on a relatively limited literature (a few occupational worker studies, some of which have study design weaknesses). Meanwhile, the community lifetime cancer risk has also been calculated for the chemical, in this case based on a large literature of animal toxicology studies, and found to be 5.3 × 10-5 (or 5.3 in 100,000). What would be your overall recommendation to the community leaders who hired you for the risk assessment? Would you recommend closing the wells? How would you describe the uncertainty related to the data? How would you explain these risks to the community?
Question 6: Managing and communicating the policy options. List three potential strategies for managing the risks faced by this community from their well water due to the gasoline tank leak. How would you identify the most vulnerable members of the population, and how would you protect them? What do you think would be the most challenging aspects of communicating the policy options to the community? How might the problem formulation process have helped you in this task?
Should cite at least two sources to support your answer for each question.