The Canadian Cancer Society’s view of the precautionary principle is that if there is a
potential for harm, then steps should be taken to mitigate risk. In the case of cosmetic
pesticides—i.e., pesticides used to enhance the appearance of a lawn or garden— precaution might result in banning them altogether. In the case of agricultural pesticides, precaution might mean looking at alternative crop patterns to help manage pest control. It is important to identify the criteria for invoking the precautionary principle in advance, especially when
dealing with a controversial subject matter such as pesticides.
The precautionary principle has had a long history. For example, in 1964 the Surgeon
General warned the public that smoking caused lung cancer, even though there was no “proof
of harm” at that time. This model of having the courage to act based on partial, but sound,
evidence should be applied to environmental issues like exposure to agricultural pesticides.
The indication of harm is the usual trigger for action and the weight of the evidence depends on how many people are exposed.
A precautionary approach is particularly important in regard to epigenetics and critical
windows of exposure. If precaution is not adopted early on it could take generations of
humans being exposed before the real effects are uncovered.
Before more regulation is enacted—such as for atrazine that has known health implications and is banned in other countries—the problem with enforcement of existing regulations needs
to be solved. It is a huge issue that is inhibiting the protection of public health.
With 8,000 new incident cases of cancer in children each year, they are an ideal group in which to study links between chemical exposures (such as pesticides) and cancer. When
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studying children, problems that plague adult epidemiological studies can be avoided, such as a long disease latency period, recall bias, and confounding exposures.
Atrazine might affect the progression and metastatic capability of breast cancer, but there is currently an absence of data regarding that mechanism. Studies have shown that atrazine also
has effects on the pituitary gland, neurodevelopment, and immune function. However, the
mechanisms of action vary and industry often uses such inconsistencies to justify keeping a
product on the market.
Patient advocates are the policy makers at the grassroots level and help drive research in many organizations. Advocates, such as those at both the American Cancer Society and the
Canadian Cancer Society, play a critical role in carrying the voice of patients forward.
The biggest challenge the CCS faces related to environmental factors in cancer is translating scientific evidence to the public. There is not much knowledge in the community about
scientific design, and the more controversial an issue, the more risk that the public will lose interest before the issue has been explained.
A national pesticide reporting program would start the process of holding people accountable for the use of toxic chemicals. This would be accomplished through an entity that enforces
violations such as failure to report use, misuse, or overuse of pesticides. As exemplified in California, a full-time reporting system can be successfully paid for by a mill tax—a tax on
the pesticide registrants.
The presumption that cancer is an inherited predisposition is not evidence based. Families, especially farming families, often share their environment, and genes and the environment
interact in very complex ways. The environment and lifestyle are more rational places than
inherited predisposition to begin a program of cancer prevention.
A number of community-based organizations work to ensure that farm workers are aware of
what the Worker Protection Standard entails. These groups often know better than the
workers themselves how they should be protected and could help contribute to the
development of a more effective worker protection model.
In every vertebrate class examined there is evidence for an endocrine mechanism consistent with the induction of estrogen. Many laboratories, including at the EPA, have shown that
atrazine induces aromatase—aromatase converts androgen to estrogen in the body. If the
FDA has approved Novartis and AstraZeneca to release an aromatase blocker to treat breast
cancer, then the EPA should ask Novartis Syngenta to stop producing atrazine, an aromatase
inducer.
Endocrine disruptors in the environment need to be studied for their potential contribution to the rising incidence of hormone-dependent cancers. Dose responses and mechanisms of
action are important aspects to consider.
There is evidence that aromatase and local estrogen production are important in prostate
cancer. Anastrazole and letrasol, two aromatase inhibitors produced by AstraZeneca and
Novartis, respectively, are being tested for treatment in prostate cancer.
In developing precautionary approaches, policy makers should be encouraged to look to
jurisdictions that have enacted these approaches successfully—such as Massachusetts’ Toxic
Use Reduction Act and Europe’s Registration, Evaluation, Authorisation and Restriction of
Chemicals (REACH) legislation.
Additional populations, crops, and states need to be studied to accurately assess the health implications of those most at risk to exposure to pesticides. The Agricultural Health Study is primarily looking at whites, but 75 percent of the agricultural workforce is Latino. Farmers in Indianapolis, IN
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states where fruits and vegetables are grown—like California and Florida—need to be studied
because that is where pesticide use is the greatest.
The burden of cancer attributable to the use of poisons in agriculture will likely remain unknown until they are taken out of the food chain and a different form of agriculture is
embraced. Organic agriculture is able to produce high yields and the nutritional quality may
be higher than conventionally grown food. The government needs to play a catalyzing role to
transform the U.S. agricultural system into one that is safe and sustainable.
A power imbalance overlies the policy failure regarding pesticides and farm workers. The
public and the disenfranchised community of farm workers must fight against a historically
powerful industry that has not had an interest or mandate to protect the rights of farm
workers. This is compounded by a regulatory structure that uses a cost-benefit analysis
weighted toward economic interests, when a public health standard is needed.