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Cleaning trees

Cleaning trees one area of research that has seen tremendous progress over the last few years is phytoremediation, or the use of certain plants to clean up toxic chemicals and elements. To give us a cleaner world, scientists are unleashing the amazing gene genie on these plants, genetically modifying them to fight the numerous polluting compounds that have accumulated over the years. Different plants clean up different chemicals. For some of them, cleaning comes naturally. Others, of course, have to be modified by geneticists before they acquire their cleaning powers.

The latest news from the world of phytoremediation tells us that Japan's Hokkaido Forest Products Institute has developed a process that helps conifer leaves clean up certain heavy metals from water. Heavy metals may have their own uses, but when it come to a better world, they are definitely not invited. Extremely toxic, these must be treated with care, or else they could damage our environment substantially. And this is certainly true for chromium, a precious metal used for plating.

Chromium compounds come in two types: those with chromium in the plus-3 state, or with three electrons, and those with chromium in its plus-6 state. Of these two, chromium-6 is by far the most toxic. It mixes readily with water, which means that it can easily escape into the ground water reserves from polluted soil and cause widespread havoc.

Large quantities of chromium-6 are generated during metal refining and plating processes, and Japan's legislation severely limits emissions from factories. However, that still leaves the polluted land and contaminated water.

The basic technologies are already in place to treat highly-polluted waste water and soil, lowering the heavy metal concentration to a more manageable level. Chromium-6, for instance, can be treated with certain chemicals to convert it to its less-harmful incarnation

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