There is an increasing concern that electromagnetic fields (EMFs) at power frequencies may have adverse health effects. Several international workshops have therefore been recently held to define the issues and the research needs to understand the health effects of these EMFs. To address health concerns a key research need is to establish the mechanisms of bioeffects of these EMFs. A related important issue that has come up is that coupling of the EMFs to the tissues in the human body is poorly understood since only simple saline-filled and metal-coated idealized models have been used to date. Knowledge of the internal electric fields and induced current densities in heterogeneous, anatomically based models is needed not only to understand the reported epidemiologic data, but also to generalize the results to other workers in the EMF environments. We propose to modify and adapt the efficient computational techniques previously proven at higher radio frequencies, such as the finite- difference time-domain method and the impedance method, for calculation of induced fields and current densities in an anatomically based model of the human body for a variety of worker exposure conditions encountered in utility and non-utility industries. We project being able to improve the resolution of these models to dimensions on the order of 1-2 mm, necessitating therefore the creation of a new improved anatomically based model of the known direction-dependent conducting properties for the skeletal muscle an a proper accounting of the interfaces between the various tissues that will affect the flow of currents. Also proposed are calculations of the internally coupled fields for occupationally encountered transient EMFs and for exposure to some typical workplace electrical appliances. Accuracy of the numerical methods will be verified experimentally by using homogeneous, and selectively inhomogeneous reduced- scale models of the human. To assess the potential for shock and burns in the EMF workplace, we would develop two new instruments, namely the contact current meter and the stored energy meter, and supply prototypes of the same for field evaluations by personnel at NIOSH and OSHA/ Using an equivalent circuit as the human surrogate, the contact current meter will measure the current that will flow for different conditions of contact such as finger or grasping contact, with or without rubber-soled shoes, and with or without safety gloves. Likewise the stored energy meter will measure the open-circuit voltage and short-circuit current for various locations of possible worker contact, allowing an evaluation of the stored energy which is related to the possibility of spark discharges for transient contacts.
