Date of Award
Honors Thesis (Open Access)
Colby College. Chemistry Dept.
D. Whitney King
Since the advent of modern herbicide use in the early twentieth century, researchers have been plagued with the obvious problem of herbicide disposal. Most herbicides are specifically designed to resist natural degradation processes so that they can remain effective in the field for a substantial amount of time. In addition, they are also made water soluble so that they can be easily applied to crops. Finally, they are specifically produced to kill undesirable plant species in the quickest and often crudest fashions. Due to these specific properties herbicides pose a general threat to other organisms living in the same geographic regions where the herbicides are sprayed. Their resistance to natural degradation and ability to be transported by water make the direct degradation of herbicides very difficult and remarkably expensive. Therefore there is a need for a quick, clean and inexpensive mechanism for the degradation of herbicides in the environment. Specifically, it is of interest to find a way to degrade herbicides present on farm equipment and in spray tanks and herbicides released in commercial spills. One of the most widely used herbicides in the United States is the triazine compound, atrazine (Figure 1). Atrazine is a selective triazine herbicide used to control broadleaf and grassy weeds found in com, sorghum, sugarcane, pineapple, Christmas trees and in conifer reforestation plantings. Atrazine can also be used as a nonselective herbicide on non-cropped industrial lands. Atrazine is currently viewed as one of the most effective and economically valuable herbicides produced. Information in recent EPA submissions quantifies the minimum dollars-and-cents value of atrazine to various sectors of US agriculture. According to studies based on data from weed scientists and farm economists, the total minimum annual economic benefit of atrazine approaches $1.66 billion . This includes an estimated minimum annual benefit of $160 million to growers of popcorn, sweet corn, citrus. sugarcane, and various nuts and fruits. along with sod farms, golf courses and nurseries (2). The data present a strong indication of atrazines importance to com yields. Based on results from more than 4,926 university field trials measuring corn yields in no-till systems and conventional tillage, statistically higher yields result when atrazine is used to control weeds , compared to other herbicides. Arrazines economic benefit to US agriculture is unparalleled by herbicides of similar chemical composition. However, despite atrazine's clean economic record the herbicide shows many undesirable effects upon non-targeted species. These effects can be classified as either toxicological or ecological.
Herbicides -- Biodegradation, Atrazine -- Biodegradation, Light -- Wave-length, Biodegradation
Recommended CitationBertram, Timothy, "Determination of the wavelength dependence on the metal catalyzed degradation of the herbicide atrazine" (2000). Honors Theses. Paper 31.
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