 |
Pesticides are chemical poisons designed to kill by upsetting fundamental biological processes. Thousands of case studies and laboratory research projects have demonstrated that pesticides often cross biological boundaries to damage non-target organisms. Yet health and environmental data are incomplete for virtually every pesticide formulation.
Some insecticides - insect-killers - can poison the nervous systems of mammals and can be acutely toxic to birds and fish. Certain fungicides - fungus-killers - can cause cancer or create allergies in mammals, inhibit fertilization in plants and destroy earthworms. Herbicides - plant-killers - can block production of detoxifing enzymes or target blood-forming tissues in mammals, and can be highly toxic to aquatic organisms. Detailed descriptions of pesticides regularly used in wine country are found in the Toxicological Profiles section of this report.
What We Do Know
Of the most commonly used pesticides in Sonoma and Napa wine country, federal and state regulatory agencies know or suspect most to cause:
- cancers (metam sodium, mancozeb, dimethoate, benomyl, propargite, oxyfluorien, oryzalin and diclobenil)
- birth defects (metam sodium, mancozeb, benomyl and oxyfluorfen)
- reproductive problems ( dimethoate and myclobutanil)
- nerve disorders (methyl bromide, inancozeb, dimethoate and chloropicrin)
They also can cause other serious long-term effects such as gene mutations, endocrine disruption, immune system depression, cirrhosis of the liver, heart problems and more.
Wine grape pesticides can be air contaminants (methyl bromide, metam sodium, mancozeb, dimethoate, benomyl, glyphosate, propargite, oxyfluorfen, oryzalin, chloropicrin, carbaryl and diclobenil) or water pollutants (simazine, oryzalin, oxyfluorfen, dimethoate, benomyl and glyphosate).
Besides affecting humans, these chemicals are toxic to:
- fish (simazine, mancozeb, dimethoate, benomyl, glyphosate, propargite, oxyfluorfen and oryzalin)
- aquatic organisms such as invertebrates, freshwater clams or plants (dimethoate, oryzalin, oxyfluorfen, propargite and glyphosate)
- birds (oryzalin, dimethoate, benomyl)
- bees (dimethoate)
- mycorrhizal fungi (methyl bromide and glyphosate)
Uncharted Territory
Despite the dangers, studies of potential toxicological effects of pesticides are not required by government agencies unless or until overt examples of a negative results are recorded over long period of time. After that, it still takes decades to plan, initiate and carry out studies. Most have never been completed. One exception has been the California Birth Defects Prevention Act, which mandates a ban on chemicals not studied by certain deadlines. Unfortunately, the California legislature last year voted to allow a special extension of the deadline for studies on methyl bromide's connection to birth defects.
Toxicological studies are not required for:
- special effects on children. Only now beginning to be explored by the EPA, this topic has to do with conditions which make children more vulnerable to injury from pesticides. Children grow new cells constantly, their bodies metabolize substances quickly and they are smaller than adults, but guidelines for legal limits for exposures are set as if the exposed person is an adult male. Many scientists believe that rising cancer rates among children are due to exposures to pesticides and other chemicals.
- individual sensitivity, the unique conditions which make some people more susceptible than others to the negative effects of certain chemicals. For example, anyone who has inherited the inability to produce certain enzymes that detoxify chemicals may be more susceptible to glyphosate, which depresses other enzymes involved in detoxification.
Pesticides, such as oryzalin, metam sodium, simazine or oxyfluorfen, which laboratory studies show affect blood and blood-forming tissues, may be especially dangerous for persons with inherited blood abnormalities or acquired blood diseases. Even sulfur, which is considered relatively low in toxicity, can be threatening to an asthmatic.
- chemical interactions such as synergism and other effects that are created as a result of mixing chemicals together. Research on chemical blends like those in pesticide formulations is limited to lethal effects and acute eye and skin effects.
- endocrine disruption, or alteration to the system that regulates hormones. Although there is evidence in nature and even in humans, damage to the endocrine system by pesticides and other chemicals is only now beginning to be considered by the EPA for future studies and regulatory action. Endocrinedisrupting chemicals often affect reproductive organs and reproduction and they are especially dangerous to fetuses or young children. This is of particular concern to scientists because of the threat to future survival of humans and other species.
- immune system depression. Hundreds of scientific studies of humans in agricultural areas in Canada and the former Soviet Union found adverse alterations to immune systems and higher rates of infectious disease than unexposed populations (WRI 1996). Studies in experimental animals prove that many pesticides have the ability to disrupt immune system flinctions following acute and even low-level exposures.
Harm on the Farms
Damage to farmland is not well researched although available data indicates that agricultural costs may be even higher than costs of adverse health effects. These costs include the expense related to purchasing and applying pesticides, which is considerable, and also factors such as:
- creation of resistance in pests, a serious problem for grape growers because of the increasing ability of various fungi to withstand most synthetic fungicides. Resistance is also on the rise with other pests such as weeds and insects
- loss of beneficial organisms, which can amplify problems because, in the absence of predators and competitors killed with pesticides, pests are often able to rebound more quickly and into greater populations. This, in turn, requires more pesticides to treat and farmers are caught on a pesticide treadmill;
- reduced soil health, which is high when populations of micro-organism are large and complex, creating a rich soil ecosystem, but low when pesticides kill organisms such as mycorrhizal fungi, essential to root growth and health, and countless other important organisms;
- damage to pollinators, which is especially troubling now since both wild and domestic honeybee populations have been severely impacted by the introduction of a highly destructive bee mite. Farmers rely on pollinators to germinate over 50% of California crops, thus pesticide damage to pollinators is a critical problem.
Contributions to Extinction
Despite high public concern for endangered species, little to nothing is known about the effects of pesticide use on rare species in wine country. Sonoma is second in the state with 33 endangered species and Napa ranks high with 16. The continued high use of pesticides could bring about more permanent losses to local biodiversity.
Environmental monitoring demonstrates that pesticide exposures are occurring to wildlife throughout California, but the significance of the findings is difficult to evaluate. Pesticides can alter food chains in ecosystems in various ways, such as by reducing or eliminating food sources or by contaminating edible organisms, but little is known about the resulting consequences for wild populations or endangered species. Information to assess the impacts of chronic exposure to pesticides is generally unavailable.
Inert But Not Impotent
Compounding the problem, the identity of chemicals which make up large portions of most pesticide formulations are kept secret by pesticide manufacturers. Called "inerts," these chemicals are added to help pesticides dissolve, spread, stick or be effective in some other way. The name does not mean that they are biologically, chemically or toxicologically inert. In fact, inerts are often highly toxic, sometimes even more toxic than the "active" ingredients which are the only part of the formulation studied for chronic and long-term health effects.
One example is the popular pesticide Roundup, in which the active ingredient glyphosate is mixed with the inert ingredient POEA, a compound three times more toxic.
An EPA list itemizes approximately 2,500 inert ingredients but does not indicate which formulations contain the chemicals. EPA considers almost 80% of them 1,981 -to be "Inerts of Unknown Toxicity" because of a lack of information, although several in this category are internationally recognized carcinogens. A large number of inerts belong to classes of chemicals that have been linked to serious health or environmental impacts. Glycol ethers, zylenes and other highly toxic solvents are among the inerts commonly used in pesticides.
The EPA continues to hide the identify of inerts to protect trade competitiveness of formulators in spite of a 1996 federal court decision in favor of environmentalists who won disclosure of the inert chemicals in several pesticide formulations. Almost two years later, public access to complete information about most pesticide formulations is still extremely limited.
|
