Academic journal article Environmental Health Perspectives

Cancer Mortality in Four Northern Wheat-Producing States

Academic journal article Environmental Health Perspectives

Cancer Mortality in Four Northern Wheat-Producing States

Article excerpt

Chlorophenoxy herbicides are used both in cereal grain agriculture and in nonagricultural settings such as right-of-ways, lawns, and parks. Minnesota, North Dakota, South Dakota, and Montana grow most of the spring and durum wheat produced in the United States. More than 90% of spring and durum wheat is treated with chlorophenoxy herbicides, in contrast to treatment of approximately 30% of winter wheat. In this ecologic study I used wheat acreage as a surrogate for exposure to chlorophenoxy herbicides. I investigated the association of chlorophenoxy herbicides with cancer mortality during 1980-1989 for selected counties based on level of agriculture ([is greater than or equal to] 20%) and rural population ([is greater than or equal to] 50%). Age-standardized cancer mortality rates were determined for grouped counties based on tertiles of wheat acreage per county or for individual counties for frequently occurring cancers. The cancer sites that showed positive trends of increasing cancer mortality with increasing wheat acreage were esophagus, stomach, rectum, pancreas, larynx, prostate, kidney and ureter, brain, thyroid, bone, and all cancers (men) and oral cavity and tongue, esophagus, stomach, liver and gall bladder and bile ducts, pancreas, cervix, ovary, bladder, and other urinary organs, and all cancers (women). Rare cancers in men and women and cancers in boys and girls were studied by comparing counties above and below the median of wheat acreage per county. There was increased mortality for cancer of the nose and eye in both men and women, brain and leukemia in both boys and girls, and all cancers in boys. These results suggest an association between cancer mortality and wheat acreage in counties of these four states. Key words: adults, agriculture, cancer mortality, children, chlorophenoxy herbicides, 2,4-D, herbicides, human, MCPA, pesticides, wheat. Environ Health Perspect 108:873-881 (2000). [Online 1 August 2000]

http://ehpnet1.niehs.nih.gov/docs/2000/108p873-881schreinemachers /abstract.html

Chlorophenoxy herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA) were first produced after the Second World War. They have been one of the most widely used class of herbicides since the mid-1960s, not only in the United States but also in other parts of the world. They are used in agriculture to control growth of broadleaf weeds in cereal grains and in nonagricultural settings to control growth of unwanted brush in rangeland, forests, noncrop land, rights-of-way, and in roadside maintenance. In addition, 2,4-D is one of the most commonly used herbicides in urban areas for the maintenance of parks, golf courses, playgrounds, playing fields, and home lawns and gardens (1-4). Chlorophenoxy herbicides are often mixed with other herbicides and fertilizer. Dioxins are unwanted contaminants (2,5-7). One of the most toxic dioxins, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a contaminant of the chlorophenoxy herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), is a potent carcinogen in animals (6). Most registrations for 2,4,5-T were canceled in 1979 by the U.S. Environmental Protection Agency (2,6-8). Contamination of 2,4-D and MCPA by TCDD is not likely (5). More than 60% of all agricultural herbicides used in the United States, including 2,4-D and MCPA, reportedly have the potential to disrupt the endocrine and/or reproductive system of animals (1).

Because chlorophenoxy herbicides are among the most common herbicides, widespread exposure to them is likely. Not only are people working in the agricultural industry exposed (e.g., farmers, farm workers, pesticide manufacturers and mixers, and crop duster pilots) but their families are also exposed because of contaminated clothing or dust tracked into the house (9). Lawn care workers and highway maintenance workers are also exposed. Other routes of exposure are drift from aerial pesticide application to crops, contamination of surface or groundwater, or walking in recently sprayed lawns and fields. …

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