For geneticist Richard Meagher, the quest to remove toxins from the environment is linked to a family tradition. He can no longer eat the fish he catches from the lake near his home in Georgia. Mercury from industry has seeped into its waters. At the bottom of the food chain, bacteria here transform this mercury into a highly toxic form called methyl mercury. As tiny organisms feed, they take in the methyl mercury of their prey and accumulate this toxic compound in their bodies.

The next predator gets a more concentrated serving and so on up the food chain. This process, known as bioaccumulation, happens in both fresh water and marine environments. Mercury concentration in top predators can be over ten million times greater than in the water.

Richard Meagher

Meagher is working in a field called phytoremediation wherein he uses plants to clean up environmental messes. According to Meagher, "we're using all that machinery, that incredible 100 million miles of roots per acre that plants can generate, to extract toxins like mercury from the soil." Some plants have a natural ability for handling toxins. Ferns can survive in arsenic-laced soil, alpine herbs can survive in zinc, mustard plants in lead and clovers in motor oil but no plants can withstand large amounts of methyl mercury. Bacteria, however, can demethylate mercury making it less toxic. Meagher decided to try and add bacterial genes into plants to enhance their capabilities. After two decades of trials and error, he succeeded in getting demethylating mercury genes into his plants. One of his plants stores mercury in its leaves while another emits it in a less harmful form as vapor.

References
»	The Meagher Laboratory's website contains more information on how plants can be used to extract, sequester and detoxify elemental and organic pollutants in a process known as phytoremediation.

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