Current densities induced in swine and rat models by power-frequency electric fields.

Measurements have been made of vector current densities induced by vertical, uniform, 60-Hz electric fields in the torsos of homogeneous models of swine and rats. The observed data were a strong function of the five grounding configurations invested: all four feet grounded, only front feet grounded, only rear feet grounded, left front and right rear feet grounded, and right front and left rear feet grounded. In the first configuration and with an exposure field strength of 10 kV/m, average total current densities induced in the torsos of pigs and rats were 34 nA/cm2 and 20 nA/cm2, respectively. The corresponding value for human exposure is about 250 nA/cm2, 7.3 and 12.5 times larger than for swine and rats, respectively. Current densities measured at 60 Hz can be linearly extrapolated to frequencies in a range extending from at least 1 Hz to 1 MHz. Human and animal current-density data can provide an improved rationale for extrapolating biological data across species. In addition, these data can be used to validate the predictions of numerical models.