MANAGING ELECTROMAGNETIC-FIELDS FROM RESIDENTIAL ELECTRODE GROUNDING SYSTEMS - A PREDECISION ANALYSIS

Several epidemiological studies have linked exposure to electromagneti c fields (EMFs) with health effects, including leukemia and brain canc er, but the research is still inconclusive. In particular, no clear ca usal mechanism has been identified by which EMFs may promote cancers. Nevertheless, the concerns raised by the positive epidemiological stud ies have led to increasing efforts to reduce EMFs from a number of sou rces. One source of EMFs are home grounding systems that are connected through water pipes in homes to water mains. This paper analyzes whet her home owners who are concerned about electromagnetic fields exposur e from home grounding systems should take any action to reduce fields. Assuming that the grounding system produces elevated magnetic fields (e.g., 2-3 mG or higher), this study investigates several readily avai lable alternatives and evaluates them with respect to five criteria: r isk reduction, cost, fire risk increase, worker risk, and electrical s hock risk. Because of the lack of conclusive evidence about an EMF-can cer relationship, this study uses a parameterized approach that makes conditional estimates of health risk depending on future research outc omes and on the nature of the EMF/health effects relationship. This ty pe of analysis, which is called predecision analysis because of its pr eliminary nature,is therefore highly dependent on a set of assumptions . Nevertheless, this predecision analysis had some fairly clear result s. First, waiting for more research or taking a fairly inexpensive cor rective action (insulating the water pipe to reduce ground current flo w) seem to be the main contenders for the best decision for many diffe rent assumptions and parameters. Second, the choice between these two actions is very sensitive to variations in assumptions and parameters. Homeowners who accept the base-cast assumptions and parameters of thi s study should prefer to wait. If any of the base-case parameters are changed to more pessimistic estimates or if psychological concerns (Li ke worry and regret) are considered, then the best action is to insula te the pipe to reduce the current flow through the water pipes. (C) 19 96 Wiley-Liss, Inc.