Summer reading: The Garden of Evil

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    Here's food for thought: I just finished "The Garden of Evil" (Durban House, 2005), an intriguing work of fiction based on the premise that common garden vegetables can be genetically manipulated to absorb toxins. In such a scenario, an innocent-looking cabbage becomes an ingestible murder weapon.  In "The Garden of Evil," author, physician and epidemiologist Chris Holmes -- who has spent much of his career investigating epidemics -- describes how this sort of bioterrorism might happen.

A sociopathic biology professor is the perpetrator. Like the Unabomber, he feels misunderstood and wronged by his colleagues. By combining his knowledge of microbiology, botany and recombinant DNA technology, he creates plants that store the heavy metal thallium in their tissues. The professor takes poisoned cole slaw to a faculty pot luck, and two days later, victims begin to experience malaise, hallucinations and gastrointestinal distress. Several die, and -- once the media get wind of the "epidemic" -- the community experiences what Holmes describes as "creeping hysteria."

            Before long, "any of the worried well who had a change in his or her bowel habits demanded immediate medical attention. Emergency room visits doubled. Medical clinics were packed with patients concerned they had been poisoned by the terrorist. They all wanted prescriptions for the magic antidote: Prussian Blue. Pharmacies were swarmed with people demanding the medication..."

            In his postscript to "The Garden of Evil," Holmes explains phytoremediation, the technique of using plants to clean up polluted environments. (It's related to bioremediation, which was used to create the oil-eating bacteria that cleaned up the Exxon Valdez spill in Alaska.) Holmes says certain plants are natural "hyperaccumulators" of metals such as nickel, copper and chromium, and heavy metals such as arsenic, cadmium and selenium. But "natural plants have only a limited capacity to accumulate these toxic metals. They soon reach a threshold and are themselves poisoned."

            However, a plant with altered DNA can be made to accumulate much greater amounts without succumbing. "It literally pumps pollutants out of the soil or water and stores it in its leaves," Holmes says. "The leaves can then be incinerated, leaving only a fraction of the plant's original mass... If the technology ever becomes cost effective, the metal can be harvested from the ash for re-sale on the chemical marketplace."

            Phytoremediation, Holmes adds, "may prove of enormous benefit for managing our fragile, polluted environment. Whether its outcome is good or evil depends on how, and for what purpose, it is used."

            Holmes, an avid gardener, is a retired Navy doctor who teaches at San Diego State University. "The Garden of Evil" is the sequel to "The Medusa Strain," an earlier novel about the threat of an anthrax attack.