The new research findings, published Feb. 1 in the journal Environmental Science and Technology, show that three transgenic lines of the Indian mustard plant, Brassica juncea, absorbed two to four times more selenium from contaminated soil than the genetically unaltered, wild-type plants.
Researchers from the University of California, Berkeley, and the Agricultural Research Service (ARS) of the U.S. Department of Agriculture teamed up for the six-week trial to see if they could replicate in field conditions the results of prior studies in laboratory greenhouses. Those previous tests showed that transgenic plants performed up to three times as well as wild plants in cleaning up selenium-polluted soil.
"Field conditions involve a million different variables, from weather to soil conditions, so results can be radically different than those in the lab," said Norman Terry, professor of plant and microbial biology at UC Berkeley's College of Natural Resources and co-lead author of the study. "It turns out that our field test results were better than those from the greenhouse, and that was a surprise."
In California, as much as 100,000 cubic meters of sediment contaminated with selenium, salt and boron remain in the San Luis Drain, a concrete-lined canal originally intended to channel irrigation wastewater from Central Valley farms to the Sacramento River Delta near Antioch. Selenium is considered an essential trace mineral for both humans and animals, but it becomes toxic at high doses. The dangers of selenium toxicity came to light in the 1980s when biologists discovered that irrigation drain water held at the Kesterson Reservoir in the San Joaquin Valley was caus
Source:University of California - Berkeley