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Organizing an Argument for a Literature Review: Example One (Course: Principles of Environmental Engineering)

Module by: The Cain Project in Engineering and Professional Communication

Summary: This exercise helps students recognize groups of topics and claims that should structure a review of published articles.

A student who had compiled a substantial set of references offered the following title and introductory paragraph to open his paper. After the introductory paragraph are shown the first sentences of each paragraph. Read through the introduction and paragraph as though you were a busy reader, skimming the paper.

Example 1

Endocrine Disrupting Compounds

The endocrine system, found in all vertebrates, is a collection of glands, hormones, and receptors that regulates biological processes from the conception of an organism through adulthood, and into old age. Within this system, there are more than fifty known hormones, each of which can have widely varying effects, but can include stimulation or inhibition of growth, regulation of metabolism, induction or suppression of apoptosis, and control of immune function. Hormones also control the reproductive cycle and development of almost all multicellular organisms. Over the past fifty years, substantial evidence has been accumulated on numerous compounds that can interfere with the normal functioning of the endocrine system. Exposure to these endocrine disrupting compounds (EDCs) can have long-term effects that may persist through several generations.

  1. The first documented case of an intentionally released chemical causing endocrine disruption occurred in 1949, when aviation crop dusters that handled DDT were found to have reduced sperm counts (Singer).
  2. The major concern with EDCs is the dramatic and permanent effects that exposure can cause when it occurs during developmental periods, although chronic exposure after maturity may present a health risk.
  3. The clinical and experimental findings that accumulated over the decades following the ban of DES have caused many researchers to consider the broader impact of all estrogenic pollutants based on data.
  4. One of the major difficulties in assessing a chemical as a potential endocrine disruptor is the lack of available assays.
  5. The EPA has initiated the Endocrine Disruption Screening Program (EDSP) in order to develop and validate methods of testing which can be used to identify chemicals with endocrine system activity.
  6. Another major problem that hinders the study and assaying of EDCs is that most people and animals are exposed to numerous contaminants simultaneously.
  7. Though restrictions on the use of some EDCs have been in place for a number of years, there continue to be high levels of concentrations in wildlife tissues.
  8. Some of the effects associated with EDC exposure in animals are abnormal thyroid function in fish (Moccia et al. 1986), demasculinization and feminization of birds (Fry and Toone 1981 ), and alteration of immune function in mammals (Martineua et al 1988).
  9. In addition to the direct effects of EDCs, some act indirectly to upset normal hormonal homeostasis.
  10. Recently it has been found that EDCs can affect transgenerational phenotypes, causing numerous developmental disease states.
  11. Besides the effect that EDCs can have on development, they can also cause pathology in mature adults.
  12. One interesting theory that has recently been presented, and illustrates the diversity of effects these compounds can have is that certain EDCs interact with the adipose tissue.
  13. The ecological destruction that EDCs can cause is alarming, and much of the early research into these compounds was in fact supported by the World Wildlife Fund.
  14. The mechanism through which organisms become desensitized or tolerant to certain EDCs is still unknown, but there has been some evidence as to how this occurs.
  15. Many of the compounds labeled as EDCs have been extensively used because they provide significant benefits in industry, medicine, and agriculture.
  16. Compounds capable of endocrine disruption have become ubiquitous in natural environments and will continue to place many populations at risk, including humans.

Now that you have read the introduction and the forecasting sentence in each paragraph, try to answer these basic questions:

  • What do you think the main point of the paper is?
  • What are the main points in support of this claim?
  • How easy was it to find the main point?
  • How was the paper organized?
  • Would you be able to answer specific questions about the paper if you were asked any?

Now review below content and look at another way of introducing and organizing this student’s excellent set of materials.

Revised Summary and Argument Sketch

Below are a revised two-paragraph introduction and an outline that shows how the student might have reorganized the topics in the draft you saw on the first two pages. The first paragraph defines endocrine disrupting compounds and establishs why they are important as both beneficial and dangerous compounds. The second paragraph narrows the focus to the need for a new approach to detection and regulation. The argument is organized to demonstrate the benefits and threats and to explain the particular challenges of testing these compounds, challenges that justify the conclusion that new methods are needed.

Many endocrine disrupting compounds (EDCs) have been used extensively in natural environments because they provide benefits in industry, medicine, and agriculture. However, despite their benefits, exposure to some of them also produces permanent serious effects when it occurs during developmental periods, and chronic exposure after maturity may also present a health risk. Disruption of sexual and reproductive functions can lead to evolutionary death for some species. Although some species can develop resistance to some of these compounds, bioaccumulation is likely to affect long-lived species. Humans are among those at risk.

Effective regulation of these compounds has been difficult because of a lack of appropriate assays and because (a) effects may persist across several generations and (b) simultaneous exposure to EDCs and other agents may confuse patterns of influence. Toxicologists have traditionally focused on high doses of toxins that can cause cancer, mutagenesis and death, but EDCs are characterized by their delayed response, low dose thresholds, and ability to affect development periods of the lifecycle selectively. A new approach to detection and regulation is needed. Interdisciplinary cooperation among several agencies and organizations will be necessary to document more completely the damages of endocrine disruption, to identify the mechanisms involved, and to develop more effective assays.

  1. Beneficial uses of EDCs create resistance to any limitations on their use. 1) Industry; 2) Medicine; 3) Agriculture.
  2. The damages of endocrine disruption are difficult to anticipate because of long delays before damage is evident and because consequences depend on species longevity and the lifecycle stage at which exposure occurs. 1) Short-term damages; 2) Long-term damages; 3) Consequences of exposure during development; 4)Consequences of chronic exposure on mature organisms.
  3. Theories of endocrine disruption processes are incomplete.
  4. Difficulties in screening and developing appropriate assays resist easy solution. 1) The time schedule; 2) Need for interdisciplinary collaboration in research.
  5. Therefore new interdisciplinary work is needed to develop a comprehensive theory and tests that can predict both short- and long-term damages from endocrine disrupting compounds.

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