Comments on: Science Wednesday: Lessons on Modern Toxicology – How Darwin Saw It Coming. http://blog.epa.gov/blog/2009/03/science-wednesday-lessons-on-modern-toxicology-how-darwin-saw-it-coming/ The EPA Blog Thu, 30 Jul 2015 11:15:11 +0000 hourly 1 http://wordpress.org/?v=4.2.1 By: David Reif http://blog.epa.gov/blog/2009/03/science-wednesday-lessons-on-modern-toxicology-how-darwin-saw-it-coming/#comment-12430 Tue, 17 Mar 2009 21:27:46 +0000 http://blog.epa.gov/blog/?p=691#comment-12430 Your questions have been major points of debate since the publication of Darwin’s theories. The meaning of “should” in your first question (second-to-last sentence of your post) has been twisted in all sorts of directions, from dispassionate survival-of-the-fittest attitudes through horrific Eugenics movements in many countries (http://www.dnai.org/e/). Here, let us assume that what “should” happen is that we do not subject people to selection via human activity (introduction of new products, ecological alterations, etc.).

Given this goal, it is very difficult to identify what might be altering selection dynamics because, in the strictest sense, only those things affecting reproductive fitness impact the selection process. Natural selection does not necessarily care about things that fail to impact how many offspring can themselves produce offspring. Using your trans-fat example, if trans-fat consumers contribute just as many offspring as non-consumers, we won’t see the traditional evolutionary effect of shifting genotype frequencies. Additionally, scientists are finding that factors such as maternal nutrition can affect epigenetic changes that do not alter DNA sequence (the traditional unit of heredity), making it even more difficult to discern how and when we are creating selective pressure.

So in summary, I agree with your post that if risk factors can be linked to negative health effects, then we should develop interventions immediately. The subtleties of if/how/when environmental agents truly affect selective processes will take generations to untangle, and the regulatory perspective on “fitness” must be necessarily broad—including concepts such as quality of life.

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By: Gazelle Rouhani http://blog.epa.gov/blog/2009/03/science-wednesday-lessons-on-modern-toxicology-how-darwin-saw-it-coming/#comment-12429 Sat, 14 Mar 2009 21:38:26 +0000 http://blog.epa.gov/blog/?p=691#comment-12429 As a current University of Miami graduate student taking an environmental health course, my concern is the continual regulation of chemicals that are incorporated in products used by the public. I think you raise an important perceptive with the concept of intent. In the development and manufacturing of products, the intent may be well-suited to benefit our health and it may years before the potential harm is realized. A great example is the introduction of trans-fats into our diets which were initially synthesized with the idea that the addition of hydrogens would make them more compact and perhaps easier to metabolize. By replacing semi-solid fats traditionally found in animal fats, trans-fats were thought to become an attractive ‘fat’ alternative for baking. The use of trans-fats in Crisco replaced use of animal fats, known to be unhealthy, decreased the need for refrigeration, and increased shelf life of baked goods. Less than one hundred years later, we have come to learn the harm of trans-fats and are now attempting to remove them from our diet. I think this clearly delineates modern-day natural selection. Inevitably, some individuals will survive while others will develop the health implications of unhealthy diets. Of course, the central tenet of public health is to identify risks and to develop interventions. Do you think, however, by regulating the introduction of chemicals in use that we are altering the natural course of what should happen? It would be unethical to stand by and allow nature to take its course but what are the potential biological implications of intervening with the dynamics of our selections process?

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By: David Reif http://blog.epa.gov/blog/2009/03/science-wednesday-lessons-on-modern-toxicology-how-darwin-saw-it-coming/#comment-12428 Fri, 13 Mar 2009 15:34:48 +0000 http://blog.epa.gov/blog/?p=691#comment-12428 First, let me say that I completely agree with the spirit of your comment: There can be no sacrifice of safety for commodity. However, I think that you are using the word “commodity” as a pejorative in implying that all new entities enter into the environment to enhance “luxuries, services, and speed”. This view misses the very important aspect of intent. Products are generally introduced with the intent of improving peoples’ lives. For example, new medicines and hybrid car batteries may contain unseen mixtures of chemicals that pose potential toxic threats, yet those same products may improve aspects of personal and environmental health. In these situations, we need objective science to quantify the positives and negatives of any new product. Eventually, such research might identify superior solutions that reduce or eliminate the negatives (e.g. safe battery materials).

Again, I agree that we cannot afford to trade safety for luxury. The points you raise are exactly the kind of important ethical questions that we need to address (with the aid of careful science) in finding a balance between delaying the release of beneficial new products and protecting the environment we all share.

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By: Susie http://blog.epa.gov/blog/2009/03/science-wednesday-lessons-on-modern-toxicology-how-darwin-saw-it-coming/#comment-12427 Thu, 12 Mar 2009 02:54:39 +0000 http://blog.epa.gov/blog/?p=691#comment-12427 I agree with this blog post right up until the end. I believe all of the unnatural chemicals and synthetic substances in this world expose humans to a threat that we are unable to deal with or quickly adapt to. Before we would even have the chance to become use to a chemical, hundreds of others are produced. In a class I took last semester, my professor said there were currently five hundred unregulated chemicals. Lead is still a significant threat, as our water supply, older homes, and certain materials still contain enough to cause brain damage and other illnesses. Our air quality is tainted by industries and power plants, inducing respiratory conditions and degrading our environment. I wonder if eventually humans will ever be able to overcome harsh environmental conditions, if evolution will cause our immune systems to strengthen and not be phased by common exposure. However, our vey technologies that put us at risk develop faster than we can test for them. The luxuries, services, and speed that our country demands require the use of sparsely tested chemicals just to keep up. At what point to we sacrifice safety for commodity? It is a classic dilemma, should the money and time be spent to protect everyone, even though only a small population is at risk, or should we trust statistics and only go as far as to protect the majority of the population? I think we need to slow down. Commodities and products can wait for the necessary testing to catch up. It may seem like an unnecessary delay, but when human and environmental healths are at stake, the time will not seem so substantial.

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