Thank you. I stand corrected.
I should have written that I discovered the site during the Bush, Jr. administration from press coverage at the time.
A search of Google Scholar yields this. The only such study I am familiar with was done at Michigan State University on the degradation of dioxins in soil. It comprises my total knowledge in this area 8^)
Dioxins are degraded by sunlight/UV. Thus the use of dioxin-containing herbicides (e.g. Agent Orange, 2,4,5-T) does not leave long-lasting dioxins on the foliage. However, any material which lands on the ground is bound to the soil. In a way this is good since the dioxins will not migrate down to the water table.
In the lab, standard solutions must be checked at least weekly since the room light slowly degrades the dioxins. It is a PIA.
Since man (and every other animal) has had dioxin in their system at very low levels during their evolution, these low levels are natural to the species. However, the ambient levels of dioxin have risen in recent time due to the activities of man, in most part due to combustion processes. No studies that I know of have addressed whether this has had a deleterious effect and if so, to what extent. Common sense, however, tells me that it probably is not a good thing.
To reduce ambient levels would require either curtailing man-made combustion, or treating all man-made combustion products before they are emitted. I don't think this is a possibility in the near future. However, the efforts to curtail global warming are a step in the right direction, IMHO.
Fortunately, plants to not take up dioxins. I was involved in an early study to determine this. We synthesized radiolabeled tetrachlorodioxin for the US Department of Agriculture for use in a study they did on uptake of dioxins in several plants. Since the analytical methods did not exist at that time to chemically determine dioxins at low levels, they could track the radioactivity to find the answer. They found that corn kernels, for example, contained no detectable dioxin. Root plants, however, had dioxin on the surface of the roots which could be washed off. My advice is to thoroughly wash root vegetables before eating.
Since animals bio-concentrate dioxins they are exposed to, limiting certain of these in the diet would be beneficial. Fish live in water which contains dioxins at very low levels. Their bodies trap a portion of them in their fatty tissues raising the level in their bodies about a factor of 3000. This takes time. Fish which are long-lived in general contain higher levels of dioxin. The US government has advisories on certain waterways against eating more than a specified number of fish per month. Also, large game fish likely have higher levels. Plant-eating animals are not exposed to equivalent levels of dioxin.
There have been several incidences of animals being contaminated with dioxins due to contaminated food. One incident mentioned in the comments above was chicken found to be contaminated with dioxin during a routine food analysis supermarket survey by the US government. The source of the contamination was due to the presence of contaminated clay which is put in the food to facilitate its ability to flow easily in the machinery which transfers it (usually via augers) from place to place during the feed's manufacture.
I was involved as a consultant to a Houston law firm in the litigation surrounding this incident. The clay contamination was of natural origin. Clay is made during the deposition of silt in lakes. It is thus stratified and can act as a 'time machine' for determining substances in the water at the time of the deposit by analyzing core samples. The deeper the sample, the older it is, and the time period can be back to prehistoric ages. The pattern of dioxins in the clay, mined from a depth of about 30 feet, was unusual. It did not match any known source.
It was found that a species of algae could manufacture dioxins. The algae were deposited, along with the silt, in a layer 30 feet below the top of the clay deposit. Since the contamination was of natural origin, and the possibility that clay could be contaminated in this way was was unknown, there was no culpable party, and the law suits evaporated. We are fortunate that our government had the foresight to monitor the food we eat for dioxin contamination.
Personally, I do not worry about dioxins in my diet. Man has evolved in the presence of dioxins and can handle the 'normal' exposure encountered in his daily life. What the government study is trying to do is to determine the level of concern for unusual exposure to dioxins. This, in turn, allows them to control the populace's exposure to dangerous levels of dioxins.
I hope this answers your questions.
If you want daily updates about dioxins try Google News
I am an analytical chemist and a pioneer in the development of analytical methods to measure dioxins at extremely low levels in a wide variety of environmental and industrial matrices from 1967 through 1994 as an employee of the Dow Chemical Company. I have published many of these seminal studies in peer-reviewed scientific journals. One of these studies was the first to establish that dioxins are formed in natural processes (such as forest fires) which produces a natural background of dioxins (at very low levels) which existed before man evolved from the apes through modern times.
As an expert in this area, I have served on an Expert Advisory Committee formed by the Canadian government to assess the impact of dioxins in that country. I was the only US citizen on the committee. The report of our findings was published by the Canadian government in 1983.
I have presented papers of my work at American Chemical Society meetings, Annual Dioxin Conference Meetings, and sat in on early meetings of toxicologists to discuss methodology and the significance of dioxin levels found in the environment and industrial settings.
I was an informal advisor to Italian government laboratories in Milan and Rome which analyzed for dioxins associated with the Seveso incident, advising them on how to calculate findings from raw data and how to present the data for interpretation by the toxicology community. This was during a time I was training Dow laboratory personnel in Germany to perform dioxin analyses.
I was involved in developing methods for analyzing Agent Orange (used as a defoliant in Vietnam) for the US Government
With this background, I have developed informed opinions about dioxins and their hazards.
Considering all the things that went wrong, it sounds like the start of a science fiction novel. Alien beings thwarted the mission and tracked the probe back to earth.
LOOK OUT!!! They're on the way!
Ships are routinely tracked using AIS transponders. There are free mapping services online. See for example:
Tracking Ship Positions Possible Worldwide with Free AIS Services
The Texas Department of Public Safety - Narcotics Service requires a form to be filled out before one starts a chemistry lab at home (or anywhere else).
In about 1994 I was an Apple fan, and had the first version of the Power PC. At that time Apple allowed the operating system to be used by other manufacturers as Apple Clones. They also had the right to make modifications to the OS.
Steve Jobs returned to Apple and breached all the contracts with these clone makers, most of whom went out of business.
Since then I refuse to purchase any Apple product. This was the only way I could think of to object to their behavior as a consumer.
I attended MIT as a freshman in 1956. During orientation, we took a test which consisted of writing a paragraph about anything.
The results of the test were used to determine whether the student would be required to take Remedial English.
Guess what... 30% failed.
I am a Ph.D. Chemist with 28 years of industrial experience (Dow Chemical) as an analytical chemist. I have over 30 publications in the scientific literature (some of them ground-breaking), have presented talks at national and international scientific meetings, and in my narrow area of expertise, was world renowned for my work in ultra-trace determination of toxic substances (mostly dioxin) in the environment.
I agree with almost everything you said. I would add the resources of the American Chemical Society (http://www.acs.org).
Some of the skills a chemist (or any scientist) needs beyond a knowledge of chemistry are (in no particular order):
1- Documenting your work in a way that stands up to legal scrutiny. (Without documenting what you have done, it is as if you never did it because no one can benefit from it.)
2- Presenting your work orally. (scientific meetings, work-group meetings, job performance reviews,
3- Knowledge of the scientific literature in your current area of endeavor. (Has what you plan to do been done before? Can you benefit from what has been done before?)
4- Planning projects. (How should you go about achieving a project's goals?)
You could help your students prepare for a degree in science by making them aware of the importance of these other skills.
Top Ten Things Overheard At The ANSI C Draft Committee Meetings: (5) All right, who's the wiseguy who stuck this trigraph stuff in here?