 |
Besides chemical and biological warfare agents, pesticides are the only toxins released purposely into the environment with the intent to kill. Like war, pesticides don't hit just the target or stay confined to neatly defined boundaries.
Documented studies dating back decades prove that farmers and farm workers who are on the front line of exposure experience greater health problems compared to others. Non-targets from humans to tiny organisms that help farmers cope with pests are injured and killed even when pesticides are applied under optimal conditions.
Nor do these chemicals remain where they are used. Instead, pesticides are notorious trespassers, moving away from the site of application to pollute water and air and expose people and the environment nearby to doses that are usually less than lethal but still are dangerous.
In a 1993 report to Congress about pesticide exposures to children, the National Research Council described exposure through outdoor air as potentially significant, particularly where suburban developments are interspersed within agricultural lands.
The Council noted that pesticides are usually applied as droplets which air movement may cause to be carried away from the target area where they were applied, and that "respiratory absorption of chemicals tends to be more rapid than absorption through other routes of exposure, because of the abundant blood supply in and the thinness of [lung tissue]."
Adverse health effects resulting from lower-level exposures have been documented regularly in medical research and case studies. Symptoms can resemble the "flu" or intoxication, and include headaches, stomach distress, skin rashes, eye problems, lung irritation and exhaustion. These are signs that can easily -- and mistakenly -- be attributed to viral and bacterial infections or allergic reactions but which are difficult to link to pesticide exposure.
Example: Methyl Bromide
In spite of their danger and their propensity to drift off target, pesticides don't require an advance warning of their use in wine country: at winery tasting rooms, nearby preschools or anywhere in between. Take the case of one common and lethal chemical applied on Sonoma and Napa vineyards when they are prepared for planting during late summer and fall. This is when 250 to 300 pounds per acre of the ozone-depleting fumigant methyl bromide are pumped into the soil to kill pests that might compete with young vines.
After application, methyl bromide evaporates at high rates, ranging from 35% to 80% (MBTOC 1994). It is odorless, colorless and slightly heavier than air. Low-level exposures can be followed six to twelve hours later by headaches, dizziness, disorientation and trembling. The behavior of exposed persons also can mimic intoxication by drugs or alcohol or cause feelings of exhaustion.
Since methyl bromide breaks down to bromine, a natural element that varies among individuals, blood tests are useless except in cases of extreme exposure. What's more, there is no antidote even when diagnosis is made and injuries can be permanent even after lower-level exposures (WHO ; TOMES).
Slight exposures to methyl bromide also may cause birth defects. In fact, a science advisory panel in California reviewed research on laboratory animals in 1994 and, convinced that evidence concerning methyl bromide's ability to cause birth defects was compelling, determined that the chemical should be categorized as a developmental toxin under the state's Drinking Water and Toxic Enforcement Act of 1984, also known as Proposition 65.
Agribiz Blocks Progress
Unfortunately, the public's right to know was trampled when plans to require advance warning of methyl bromide field applications were dropped after Governor Pete Wilson intervened after pleas from agricultural interests. The governor blocked the regulation even though state tests and models of the movement of methyl bromide under various weather patterns showed that the fumigant could drift up to four miles at amounts considered excessive under Proposition 65 standards for protection from birth defects (DPR 199x).
Recent tests with sophisticated new equipment conducted by the Washington, D.C.-based Environmental Working Group show that methyl bromide drifts off-site at concentrations above state-allowed limits. The tests, conducted during soil fumigations allowed by the Department of Pesticide Regulation and approved by county agricultural commissioners, found methyl bromide at excessive levels in backyards of people more than 250 feet from fumigations, including the backyard of a preschool (EWG 1996, 1997).
Catch the Drift
Although testing for drift from pesticide applications in wine country is almost non-existent, there is evidence that the chemicals accumulate off-site at levels sufficient to cause short-term illnesses and even lasting injuries. For example:
- The prestigious National Research Council in 1993 characterized the amount of drift from agricultural application as "considerable," ranging from 5% under optimal, low-wind conditions, to a enormous 60% under more typical conditions.
- A 1989 study by the California Department of Food and Agriculture found that pesticides applied to vineyards deposited residues on produce grown on nearby fields in all tests that were conducted and concluded that fog -- a common early-morning weather condition during wine country summers -- and other weather factors had moved the chemicals.
- Up to 14 to 78% of glyphosate, the active ingredient of the increasingly popular wine country herbicide Roundup, has been found to drift off-site as a result of ground spraying (Freedman 1990, 1991). Glyphosate has been documented to affect plants as far as 131 feet away, and residues have been detected 1,312 feet downwind (Marrs 1993; Yates 1978). POEA, the surfactant mixed with glyphosate to improve its effectiveness, is harmful to skin and eyes at low doses.
- Goal, another popular wine country herbicide, contains the cancer-causing chemical tetrachloroethylene, a cancer-causing chemical which readily evaporates to air where up to one-half can persist for up to eight months.
- A vineyard mite-killer, dimethoate evaporates from soil at high rates, from 23 to 40 % of the total dose applied (Pease 1996) and is readily absorbed through the skin and lungs to act as a nerve poison.
- According to the state's Department of Pesticide Regulation, sulfur, the #1 wine country pesticide, can drift off-site at rates high enough that it could cause or exacerbate asthma, a respiratory condition which is on the rise throughout the population, particularly among children.
Statistically, the chances that you can be exposed to a harmful, low-level dose of pesticides increases in proportion to the amount of chemical released into the environment at any one time. Also acting as factors are weather conditions, the expertise of the applicator, the age and worthiness of the application equipment and the types of chemicals applied. Such a welter of confounding factors makes being near pesticide applications a risky business, especially for pregnant women, the infirm, the elderly and growing children.
|
