Transgenic Mustard Cleans Up Soils

Roland Piquepaille writes "Researchers have genetically modified a common plant, the Indian mustard, to absorb more selenium, a toxic heavy metal found in soils polluted by irrigation wastewater. The transgenic plants were four times more efficient at swallowing selenium than natural ones in a contaminated area of California's Central Valley, according to articles from Nature and Wired News. These field tests are only experiments, but the researchers also want to add genes to other plants to remove different toxic materials from soils, such as mercury. What would happen if such transgenic plants filled with dangerous chemicals start to crossbreed with natural ones? Or if an insect eats these plants before being eaten itself in the natural food chain, leading to some selenium in our food? Read more and tell me what you think."

Comments

Selenium (Se) is hardly a "toxic heavy metal"

[jd]

It can't exactly be called heavy, at an atomic mass of 34. Nor is it toxic (except in high doses, at which point it rots the brain and can cause birth defects). In fact, in low to moderate doses, it is considered an essential element. Elemental Selenium is connected with many processes, including some cellular defenses against carcinogens.

HOWEVER, that only applies to the elemental form. Certain compounds containing Selenium are highly toxic, and it is my guess that this is what the genetic engineers were interested in.

To quote from WebElements:

Selenium can be prepared with either an amorphous or crystalline structure. Crystalline monoclinic selenium is deep red; crystalline hexagonal selenium, the most stable variety, is a metallic grey (see picture above). Elemental selenium is relatively nontoxic and is considered to be an essential trace element. However, hydrogen selenide (H2Se) and other selenium compounds are extremely toxic, and resemble arsenic in their physiological reactions. Hydrogen selenide in a concentration of 1.5 ppm is intolerable to man. Selenium occurs in some soils in amounts sufficient to produce serious effects on animals feeding on plants such as locoweed (an American plant) grown in such soils.