Risks Associated With Pharm and Industrial Crops?

The major concern at this point is that that non-food substances will contaminate the food supply. Substances intended for use as human drugs are especially problematic because they are intended to be biologically active in people.

Below is an overview of some potential harms to human and animal health and ecosystems, followed by a section on how genes might escape from the fields in which they will be grown.

Potential harms to human and animal health
The novel chemicals produced by pharm and industrial plants are generally proteins or short polypeptides. (Some novel proteins, in turn, produce chemicals that usually are not proteins.) Both proteins and non-proteins can harm people and animals. Some proteins can act, among other things, as toxins, hormones, or allergens.

Chemicals vary in form and activity through their production cycle and are not always harmful. To illustrate, hirudin, a powerful blood thinner for treatment of heart attacks and strokes, was grown in canola as an inactive compound: only after extraction and purification from canola seeds did it become biologically active.

In addition, the intended mode of use can affect the likelihood of harm. Just because a substance would be bioactive if injected, for example, does not mean that it would be harmful if ingested.

Some of the most problemmatic substances include toxins, hormones, and allergens.

• Toxins
  Avidin is an example of a potential toxin. Avidin binds extremely tightly, essentially irreversibly, to biotin, a B vitamin necessary for basic metabolism. The tightness of the avidin-biotin bond makes avidin useful as a tool in research laboratories. Binding biotin effectively inactivates it, which can lead to biotin deficiency in living beings, including humans.

  Biotin deficiency in humans (www.emedicine.com/ped/topic238.htm ) affects first the skin, then the central and peripheral nervous systems and intestinal tract. If allowed to progress without treatment, biotin deficiency can be serious.

  Because biotin is an essential nutrient in almost all organisms--deer, squirrels, mice, and birds--browsing in avidin-corn fields may also be affected, as might plants, earthworms, and soil microorganisms. (In view of its toxic potential, some researchers are exploring its possible use as a broad-spectrum biopesticide.)

• Hormones
  Hormones are of particular concern because they can produce substantial physiological effects in minute doses. Higher than normal levels of human growth hormone, for example, can cause giantism in children and acromegaly (overgrowth of bone and connective tissue associated with reduced life expectancy) in adults.

  Hormones are often developed as drugs and some are being developed in pharm plants. For example, human growth hormone, used to treat hypopituitary dwarfism in children, has been produced in transgenic tobacco. Some chemicals may mimic hormones and thereby disrupt endocrine function.

• Allergens
  Substances that can induce an allergic response are called allergens. Proteins that elicit immune responses upon ingestion in food are called food allergens and adding new proteins to food crops via genetic engineering may suddenly render familiar food dangerous to sensitive populations. Most proteins do not act as food allergens in humans, but the relatively few that do can be very dangerous. Proteins can also elicit immune responses if injected.

  Plant-derived pharmaceutical and industrial proteins have the potential to cause unintended immune or sensitization responses in people who might unknowingly consume them as well as in patients treated with them. Plants modify the proteins they produce differently than do mammals and other organisms, and these modifications may affect characteristics related to allergenicity.

Routes of exposure to people and livestock-the food and feed system
Since most pharm and industrial plants are also the crops that provide food for people and feed for livestock, a major concern is the contamination of the food and feed supplies. Pharm and industrial plants have two major routes into the food and feed system: seed mixing and pollen flow.

• Seed mixing
  Physical mixing of seeds can occur during seed production, on the farm as a result of using the same machinery to plant or harvest both food crops and pharm and industrial crops, during seed storage or transport, or at the grain elevator or mill.

• Pollen flow
  Pollen flow is a more indirect way of introducing new genes into food. Wind-borne pollen from corn, currently the most popular pharm and industrial crop, can travel more than 50 yards, making possible fertilization of nearby corn, intended for food, by pharm or industrial plants. As a result, unsuspecting farmers who did not plant pharm corn could nevertheless wind up with food and feed crops contaminated with drugs, harvest them, and offer them for sale to mills. If seed corn is contaminated with drug genes, farmers could unknowingly plant food and feed corn containing biologically active proteins.

  Pollen flow is an even wider route of exposure when plants like canola are used as pharm or industrial crops. Reportedly, canola pollen can spread as far as 15 miles from a parent plant and can not only fertilize other canola plants, but other crop plants (including turnip, Chinese cabbage, rutabaga and fodder rape) as well.

In situations where farmers save harvested seed to plant the next growing season, the contaminating genes and gene products may persist year after year.

Routes of exposure to the environment

Novel pharm and industrial substances have many routes to the environment. Since genetic engineers often cannot completely confine expression of new genes to particular tissues, pharm and industrial proteins will probably be produced throughout the plants. As discussed above, most of the pharm and industrial genes will be carried, and sometimes expressed, in pollen.

• Grazing wildlife
  Even if all the pollen, as well as the seeds and other plant material, associated with every pharm and industrial crop remained within the confines of the fields in which they were planted, wildlife could still be exposed. As anyone who has attempted to keep deer out of a vegetable garden or birds from fruit trees can attest, animal consumption of field crops is essentially unavoidable.

• Pollinators, herbivorous insects, and soil inhabitants
  Pollinators and herbivorous insects will undoubtedly frequent pharm and industrial crop fields as well. Microbes and other animals present in the soils of pharm and industrial crop fields will also be exposed to the compounds produced in these plants via a process scientists refer to as "rhizosecretion" (the exudation of substances from plant roots) or when the agricultural byproducts of these crops are plowed back into the earth to "dispose" of them through composting.

• Weedy relatives
  Although corn and soybeans do not have wild and weedy relatives in the United States, canola and other important plants do. Canola pollen flow could create a wild mustard weed capable of producing a pharm or industrial compound, and such a weed would likely need little human intervention, as compared to a crop plant, to perpetuate itself. Pharm and industrial canola crops thereby threaten not only human food and animal feed supplies but also the greater environment with exposure to biologically active compounds.

• Bioaccumulation
  Some biopharmaceuticals may have physiochemical properties that could make them persist in the environment or cause them to accumulate in living organisms, dramatically increasing their potential to contaminate ecosystems and their capacity to eventually make their way into the human and farm animal food chains.