“Radiation Limit” is a permanent installation for the campuses of research universities or hospitals that engaged in radiation experimentation on human subjects. The installation consists of plantings of Spiderwort, a plant native to North America that is used to detect the presence of radiation, and contact microphones buried slightly underground and connected to mixer and low-power FM transmitter. The highly sensitive contact microphones pick up the subtle root and microbial activity of the Spiderwort plants as they grow as well as the vibrations of passing footsteps. These sounds are mixed together and broadcast via low power (4-40 watt) radio to the surroundings. Viewers are provided with portable radios to detect the sonic activity, much as the original experimenters used Geiger counters and other instrumentation to measure exposure to otherwise invisible radiation.
During the cold war, hundreds of people where exposed to radiation without giving informed consent during experiments sponsored by the military, the Department of Energy, and various hospitals and research universities. Many of these experiments were conducted on prisoners, semi-literate people, and the disabled. Some of the most significant universities in the country, including the University of Pennsylvania and the University of Oregon School of Medicine (now Oregon Health & Science University), were involved.
Spiderwort has been called “nature’s radiation detector” because its stamens change color in the presence of radiation doses as low as 150 millirems. It has a long history of medicinal use by Native Americans, who crushed the leaves to treat insect bites and brewed it into a tea to treat menstrual symptoms. Europeans who brought the plant back from North America used it to treat “Tarantism” a disease thought to be caused by the bite of the Taratula whose symptoms included trembling, fever, sweats, and depression and whose only other known remedy was dancing to exhaustion, hence the “Tarantella,” a southern Italian dance. Though its effectiveness at preventing frenzied dancing has not been scientifically confirmed, independent studies at Brookhaven National Laboratory and Kyoto University have established Spiderwort’s effectiveness as a biological radiation detector. A close relative of sedges, lilies and other wetland species, Spiderwort requires a semi-shaded, relatively damp location. As such, it is well-suited to rain gardens at the dripline of trees and near footpaths.
