Dioxin

These regulations have been very successful, dramatically reducing dioxin emissions and making modern waste-to-energy systems one of the cleanest sources of electricity. (*) Duration of central eclipse.. As a result, EPA implemented new emissions requirements. Selected past and upcoming eclipses are:. When the original EPA inventory of dioxin sources was done in 1987, incineration represented over 80% of known dioxin sources. Eclipses where the path of totality crosses major population centres generate the most interest in the general public. Incineration of municipal solid waste, medical waste, sewage sludge, and hazardous waste together produce less than 3% of all dioxin emissions. Although there is a total eclipse visible somewhere on Earth most years, some are more conveniently observed than others.

Modern waste incinerators are equipped with pollution control equipment which reduces dioxin emissions to insignificant levels. [1]. Long term studies of the members of Ranch Hand have thus far uncovered a possibility of elevated risks of diabetes. Like a transit of a planet it will not get dark. These were members of Operation Ranch Hand. The satellite passes over the face of the Sun in about a second, typically. The only exception existed for those who directly handled Agent Orange. This means the best you can get is a satellite transit, but these events are difficult to watch, because the zone of visibility is very small.

The Center for Disease Control found that dioxin levels in Vietnam veterans [4] were in no way atypical when compared against the rest of the population. At the altitude of the International Space Station, for example, an object would need to be about 3.35 km across to blot the Sun out entirely. The most recent study, paid for by the National Academy of Sciences, was released in an April 2003 report. But none are large enough to cause an eclipse. US veterans' groups and Vietnamese groups, including the Vietnamese government, have convened scientific studies to explore their belief that dioxins were responsible for a host of disorders, including tens of thousands of birth defects in children, amongst Vietnam veterans as well as an estimated one million Vietnamese, through their exposure to Agent Orange during the Vietnam War, which was found to be highly contaminated with TCDD. Artificial satellites can also get in the line between Earth and Sun. Other possible effects may be. When no such planet was found during such an eclipse, the possibility of its existence was ruled out.

This is the only known direct result of dioxin exposure at levels below the lethal dose. At one time, some scientists — including Albert Einstein — hypothesized that there may have been a planet even closer to the Sun than Mercury; the only way to confirm its existence would have been to observe it during a total solar eclipse. Excessive exposure to dioxin may cause a severe form of persistent acne, known as chloracne. More common — but still quite rare — is a conjunction of any planet (not confined exclusively to Mercury or Venus) at the time a total solar eclipse, in which event the planet will be visible very near the eclipsed Sun, when without the eclipse it would have been lost in the Sun's glare. Dioxins build up in living tissue (bioaccumulate) over time, so even small exposures may accumulate to dangerous levels. This was the lowest time difference between a transit of a planet and a solar eclipse in the historical past. It is even controversially discussed if dioxins might have a non-linear dose-response curve with beneficial health effects in a certain lower dose range, a phenomenon called hormesis. Only 5 hours after the transit of Venus on June 4, 1769 there was a total solar eclipse, which was visible in Northern America, Europe and Northern Asia as partial solar eclipse.

The use of these materials means that all modern humans receive (at least) a very small daily dose of dioxin—however, it is disputed whether such exceptionally tiny exposures have any clinical relevance. The next anticipated simultaneous occurrence of a Solar eclipse and a transit of Mercury will be on July 5, 6757, and of a Solar eclipse and a transit of Venus is expected on April 5, 15232. Such materials include tampons, and a wide variety of food packaging substances. But these events are extremely rare because of their short durations. Dioxins are present in minuscule amounts in a wide range of materials used by humans — including practically all substances manufactured using plastics, resins or bleaches. In principle, the simultaneous occurrence of a Solar eclipse and a transit of a planet is possible. See Agent Orange for more on contamination problems in the 1960s. On these occasions, an object — especially a planet (often Mercury) — may be visible near the sunrise or sunset point of the horizon when it could not have been seen without the eclipse.

Higher levels of chlorination require higher reaction temperatures and greater dioxin production. When this occurs shortly before the former or after the latter, the sky will appear much darker than it would otherwise be immediately before sunrise or after sunset. Affected compounds include the wood preservative pentachlorophenol, and also herbicides such as 2,4-dichlorophenoxyacetic acid (or 2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). It is possible for a solar eclipse to attain totality (or in the event of a partial eclipse, near totality) before sunrise or after sunset from a particular location. Dioxins are also generated in reactions that do not involve burning — such as bleaching fibers for paper or textiles, and in the manufacture of chlorinated phenols, particularly when reaction temperature is not well controlled. During a partial eclipse, the light spots will show the partial shape of the sun, as seen on the picture. Incineration is now a very minor contributor to dioxin emissions. These are images of the sun.

Incinerator emissions of dioxins have been reduced by over 90% as a result of new emissions control requirements. Normally the spots of light which fall through the small openings between the leaves of a tree, have a circular shape. Chemical Engineering, December 2002 has a detailed article on this issue. During a solar eclipse special observations can be done with the unaided eye. The most common method of reducing dioxins reforming or forming de novo is through rapid (30 millisecond) quenching of the exhaust gases through that 400°C window. Note that the modern conventional dates are different by a year or two, and that these two eclipse records have been ignored so far. In incineration, dioxins can also reform in the atmosphere above the stack as the exhaust gases cool through a temperature window of 600 to 200°C. The sky suddenly darkened in the middle of the sky, well after the battles of Thermopylae and Salamis, after the departure of Mardonius to Thessaly at the beginning of the spring of (477 BC) and his second attack on Athens, after the return of Cleombrotus to Sparta.

Nevertheless, chlorine tobacco pesticides and chlorine-bleached cigarette papers remain legal, with no warning required to consumers. Herodotus (book IX, 10, book VIII, 131, and book IX, 1) reports that another solar eclipse was observed in Sparta during the next year, on August 1, 477 BC. Since then, the USA classified dioxin as a Known Human Carcinogen, and the USA signed the Stockholm Convention on POPs to globally phase out dioxin and 11 other of the worst industrial pollutants. An annular eclipse of the Sun occurred at Sardis on February 17, 478 BC, while Xerxes was departing for his expedition against Greece, as Herodotus, VII, 37 recorded ([Hind and Chambers, 1889: 323] considered this absolute date more than a century ago). Dioxin cannot come from the tobacco or any natural plant. One likely candidate took place on May 28, 585 BC, probably near the Halys river in the middle of modern Turkey. In that same document, the EPA acknowledged that dioxin is "anthropogenic" (man-made, "not likely in nature"). Exactly which eclipse was involved has remained uncertain, although the issue has been studied by hundreds of ancient and modern authorities.

Dioxin in cigarette smoke was noted as "understudied" by the EPA in its "Re-Evaluating Dioxin" (1995). Soldiers on both sides put down their weapons and declared peace as a result of the eclipse. Dioxins are also in smoke from typical cigarettes, those with chlorine-bleached paper and residues of many chlorine pesticides. Herodotus wrote that Thales of Milete predicted an eclipse which occurred during a war between the Medians and the Lydians. These sources together account for nearly 80% of dioxin emissions. For a discussion, see the text by Stephenson. According to the most recent EPA data the major sources of dioxin are:. There have been other claims to date earlier eclipses, in Babylon and also in China, but these are highly disputed and rely on much supposition.

Dioxins are produced in small concentrations when organic material is burned in the presence of chlorine, whether the chlorine is present as chloride ions or as organochlorine compounds, so they are widely produced in many contexts. This is the earliest solar eclipse that can be exactly dated. The WHO still recommends breast feeding for its other benefits. A solar eclipse of 15 June 763 BC mentioned in an Assyrian text is important for the Chronology of the Ancient Orient. Breast fed children usually have substantially higher dioxin body burdens than non breast fed children until they are about 8 to 10 years old. After a Saros cycle finishes, a new Saros cycle begins 1 Inex later (hence its name: in-ex). Children's body burdens are often many times above the amount implied by tolerable intakes which are based on body weight. The Inex cycle is itself a poor cycle, but it is very convenient in the classification of eclipse cycles.

Children are passed substantial body burdens by their mothers, and breast feeding increases the child's body burden. The Saros cycle is probably the most well known, and one of the best, eclipse cycles. Most controversial is the US EPA assessment's (draft) finding that any reference dose that were to be set would be far below current average intakes. Two such cycles are the Saros and the Inex. Few facilities have constant sampling. If the date and time of a solar eclipse is known, it is possible to predict other eclipses using eclipse cycles. In Belgium, through the introduction of a process called AMESA, constant sampling showed that periodic sampling understated emissions by a factor of 30 to 50 times. Normally this is not visible because the photosphere is much brighter than the corona.

In many developed nations there are now emissions regulations which have alleviated some concerns, although the lack of constant sampling of dioxin emissions causes concern about the understatement of emissions. For astronomers, a total solar eclipse forms a rare opportunity to observe the corona (the outer layer of the Sun's atmosphere). Inhalation has been a problem for people living near substantial point sources where emissions are not adequately controlled. (eclipse predictions by Fred Espenak, NASA/GSFC.). Occupational exposure is an issue for some in the chemical industry, or in the application of chemicals, notably herbicides. The longest total solar eclipse during the 8,000-year period from 3000 BC to 5000 AD will occur on July 16, 2186, when totality will last 7 min 29 s. [1]. The next eclipse of comparable duration will not occur until June 25, 2150.

Dioxin enters the general population almost exclusively from ingestion of food, specifically through the consumption of fish, meat, and dairy products since dioxins are fat-soluble and readily climb the food chain. Observers aboard a Concorde aircraft were able to stretch totality to about 74 minutes by flying along the path of the Moon's umbra. Tolerable daily, monthly or annual intakes have been set by the World Health Organization and a number of governments. The last time this happened was June 30, 1973. Australia, New Zealand and the United Kingdom all have substantial research into body burdens and sources. During each millennium there are typically fewer than 10 total solar eclipses exceeding 7 minutes. The United States Environmental Protection Agency Dioxin Reassessment Report is possibly the most comprehensive review of dioxin, but other countries now have substantial research. Totality can never last more than 7 min 40 s, and is usually much shorter.

. Then, after waiting so long, the total eclipse only lasts for a few minutes, as the Moon's umbra moves eastward at over 1700 km/h.
. Although they occur somewhere on Earth approximately every 18 months, it has been estimated that they recur at any given place only once every 370 years, on average (Stephenson, p.54). The treaty obliges signatories to take measures to eliminate where possible, and minimize where not possible to eliminate, all sources of dioxin. Total solar eclipses are rare events. Dioxins and other Persistent Organic Pollutants (POPs) are subject to the Stockholm Convention. Outside of the central track, a partial eclipse can usually be seen over a much larger area of the Earth.

The TEFs have been developed from detailed assessment of literature data to facilitate both risk assessment and regulatory control. In the most favourable circumstances, when a total eclipse occurs very close to perigee, the track can be over 250 km wide and the duration of totality may be over 7 minutes. TEFs for mammalian species are generally applicable to human risk calculations. The width of the track of a central eclipse varies according to the relative apparent diameters of the Sun and Moon. TEFs are consensus values and, because of the strong species dependence for toxicity, are listed separately for mammals, fish and birds. The Earth is also rotating from west to east, but the umbra always moves faster than any given point on the Earth's surface, so it almost always appears to move in a roughly west-east direction across a map of the Earth (there are some rare exceptions to this which can occur during an eclipse of the midnight sun in arctic or antarctic regions). By convention it is assigned a toxicity rating or Toxic Equivalence Factor (TEF) of 1.0 with the remaining PCDD/Fs being assigned lower relative values. During a central eclipse, the Moon's umbra (or antumbra, in the case of an annular eclipse) moves rapidly from west to east across the Earth.

2,3,7,8-tetrachloro dibenzene-para-dioxin is the most toxic of the congeners. However, some are visible only as partial eclipses, because the umbra passes either above or below the earth, and others are central only in remote regions of the arctic or antarctic. Out of the 210 PCDD/F compounds in total, only 17 congeners (7 PCDDs and 10 PCDFs) have chlorine atoms in the relevant positions to be considered toxic by the NATO/CCMS international toxic equivalent (I-TEQ) scheme. This means that in any given year, there will always be at least two solar eclipses, and there can be as many as five. The toxicity of PCDD/F is dependant on the number and position of the chlorine atoms, with only congeners that have chlorines in the 2,3,7,and 8 positions have any observable toxicity. Sometimes the New Moon occurs close enough to a node during two consecutive months. There are 210 different PCDD/F congeners, comprising of 75 PCDD's and 135 PCDF's. Therefore, the New Moon occurs close to the nodes at two periods of the year approximately six months apart, and there will always be at least one solar eclipse during these periods.

Chlorine atoms are attached to the basic structure at 8 different places on the molecule, numbered from 1 to 10. The Moon's orbit intersects with the ecliptic at the two nodes that are 180 degrees apart. The basic structure of PCDD/F's comprises of two benzene rings joined by either a single (furan) or a double oxygen bridge (dioxin). The time between one perigee and the next is known as the anomalistic month. PCDD/F's have been shown to bioaccumulate in humans and wildlife due to their lipophilic properties. Finally, the Moon's perigee is moving forwards in its orbit, and makes a complete circuit in about 9 years. Dioxin is the popular name for the family of chlorinated organic compounds comprising of Polychlorinated Dibenzo Furans (PCDF) and Polychlorinated Dibenzo Dioxins (PCDD). This period is called the draconitic month.

Dioxin was described as a mind-altering substance, that caused depression and would definitely cause the person to commit suicide, sooner or later. This means that the time between each passage of the Moon through the ascending node is slightly shorter than the sidereal month. One news report explained, that during the cold war, the KGB used dioxin to induce suicides. However, the nodes of the Moon's orbit are gradually moving in a retrograde motion, due the the action of the Sun's gravity on the Moon's motion, and they make a complete circuit every 18.5 years. Although experts suggest his face could clear up after several years, it is highly unlikely. The Moon crosses from south to north of the ecliptic at its ascending node. This is the first known case of a single high dose of TCDD dioxin poisoning. This is known as the synodic month, and corresponds to what is commonly called the lunar month.

In 2004, a notable individual case of dioxin poisoning, Ukrainian politician Viktor Yushchenko was exposed to the second-largest measured dose of dioxins, according to the reports of the physicians responsible for diagnosing him. This means that the average time between one New Moon and the next is longer, and is approximately 29.6 days. These patients were provided with olestra to accelerate dioxin elimination. However, during one sidereal month, the Earth has moved on in its orbit around the Sun. The same study also covered a second subject who had received a dosage equivalent to 2,900 times the normal level, who apparently suffered no notable negative effects other than chloracne. This is known as the sidereal month. However, other notable laboratory tests, such as immune function tests, were relatively normal. The Moon orbits the Earth in approximately 27.3 days, relative to a fixed frame of reference.

She suffered from chloracne, nausea, vomiting, epigastric pain, loss of appetite, leukocytosis, anemia, amenorrhoea and thrombocytopenia. It is only when the Moon is closer to the Earth than average (near its perigee) that a total eclipse occurs. In a 2001 case study [5], physicians reported clinical changes in a 30 year old woman who had been exposed to a massive dosage (144,000 pg/g blood fat) of dioxin equal to 16,000 times the normal body level; the highest dose of dioxin ever recorded in a human. On average, the Moon appears to be slightly smaller than the Sun, so the majority (about 60%) of central eclipses are annular. The scandal that followed caused a landslide in the elections one month later. This means that the apparent size of the Moon is sometimes larger or smaller than average, and it is this effect that leads to the difference between total and annular eclipses (the distance of the Earth from the Sun also varies during the year, but this is a smaller effect). 7,000,000 chickens and 60,000 pigs had to be slaughtered. The Moon's orbit is also elliptical, which means that the distance of the Moon from the Earth can vary by about 6% from its average value.

In May 1999, there was a dioxin crisis in Belgium: quantities of dioxin had entered the food chain through contaminated animal feed. A solar eclipse can occur only when the New Moon occurs close to one of the points (known as nodes) where the Moon's orbit crosses the ecliptic – hence the name. No direct consequences of this incident have thus far been recorded. Because of this, at the time of a New Moon, the Moon will usually pass above or below the Sun. A possibly large amount of dioxins was flushed from the factory into the Labe river during the 2002 European flood. The Moon's orbit around the Earth is inclined at an angle of just over 5 degrees to the plane of the Earth's orbit around the Sun (the ecliptic). Dozens of them fell seriously ill. The larger light gray area is the penumbra, in which a partial eclipse will be seen.

Workers in this factory were exposed to high concentrations of dioxins at that time. The small area where the umbra touches the Earth's surface is where a total eclipse will be seen. In the 1960s, parts of the Spolana chemical plant in Neratovice, Czechoslovakia, were heavily contaminated by dioxins, when the herbicide 2,4,5-T (also a component of Agent Orange) was produced there. The dark gray region to the right of the moon is the umbra, where the Sun is completely obscured by the Moon. Dioxin also caused the 1983 evacuation of Times Beach, Missouri. The diagram to the right shows the alignment of the Sun, Moon and Earth at a solar eclipse. In 1978, dioxin was one of the contaminants that forced the evacuation of the Love Canal neighborhood of Niagara Falls, New York. For more information on safe eclipse viewing, see:.

In 1976 large amounts of dioxin were released in an industrial accident at Seveso, although no human fatalities or birth defects occurred. Note that it is never safe to look at an annular or partial eclipse directly, because the Sun's disk is never completely covered during this type of eclipse. In the 1960s Philips-Duphar produced 2250 tonnes of 'Agent Orange' for the US Army. The exact time and duration of totality for the location from which the eclipse is being observed should be determined from a reliable source (local astronomers, etc.). Four people die of dioxin poisoning, and 50 more suffer severe health problems. However, it is important to stop directly viewing the Sun promptly at the end of totality. In 1963 a dioxin cloud escapes after an explosion in a Philips-Duphar plant (now Solvay Group) near Amsterdam. The Sun's faint corona will be visible, and even the chromosphere, solar prominences, and possibly even a solar flare may be seen.

And at least in laboratory animals, increased rates of liver and lung cancer are observed. Contrary to popular belief, it is safe to observe the total phase of a total solar eclipse directly with the unaided eye, binoculars or a telescope, when the Sun's photosphere is completely covered by the Moon; indeed, this is a very spectacular and beautiful sight, and it is too dim to be seen through filters. Diabetes. These precautions apply to viewing the Sun at any time except during the totality phase of a total solar eclipse (see below). Birth defects. The optical viewfinders provided with some video and digital cameras are not safe. Endometriosis. Viewing the Sun's disk on a video display screen (provided by a video camera or digital camera) is safe, although the camera itself may be damaged by direct exposure to the Sun.

Damage to the Immune systems.[3]. However, care must be taken to ensure that no one looks through the projector (telescope, pinhole, etc.) directly. Developmental abnormalities in the enamel of children's teeth.[2]. The projected image of the Sun can then be safely viewed; this technique can be used to observe sunspots, as well as eclipses. Diesel trucks. This can be done by projecting an image of the disk onto a white piece of paper or card using a pair of binoculars (with one of the lenses covered), a telescope, or another piece of cardboard with a small hole in it (about 1 mm diameter), often called a pinhole camera. Metal smelting. The safest way to view the Sun's disk is by indirect projection.

Residential wood burning. Only properly designed and certified solar filters should ever be used for direct viewing of the Sun's disk. Coal fired utilities. Sunglasses are not safe, since they do not block the harmful and invisible infrared radiation which causes retinal damage. Land application of sewage sludge. The Sun's disk can be viewed using appropriate filtration to block the harmful part of the Sun's radiation. Trash burn barrels;. Viewing the Sun during partial and annular eclipses (and during total eclipses outside the brief period of totality) requires special eye protection, or indirect viewing methods.

Viewing the Sun's disk through any kind of optical aid (binoculars, a telescope, or even an optical camera viewfinder) is even more hazardous, although just viewing it with the naked eye can easily cause damage. Unfortunately, looking at the Sun during an eclipse is just as dangerous as looking at it outside an eclipse, except during the brief period of totality, when the Sun's disk is completely covered (totality occurs only during a total eclipse and only very briefly—it does not occur during a partial or annular eclipse). However, during an eclipse, with so much of the Sun covered, it is easier and more tempting to stare at it. Under normal conditions, the Sun is so bright that it's difficult to stare at it directly, so there is no tendency to look at it in a way that might damage the eye.

The retina has no sensitivity to pain, and the effects of retinal damage may not appear for hours, so there is no warning that injury is occurring. This damage can result in permanent impairment of vision, up to and including blindness. Looking directly at the photosphere of the Sun (the bright disk of the Sun itself), even for just a few seconds, can cause permanent damage to the retina of the eye, because of the intense visible and invisible radiation that the photosphere emits. When the Moon disappears at Full Moon by passing into Earth's shadow, the event is properly called an eclipse, but when the Moon passes in front of the Sun, we see an occultation of the Sun by the Moon.

Properly speaking, an eclipse occurs when one object passes into the shadow cast by another object. The term eclipse is actually a misnomer: The phenomenon of the Moon passing in front of the Sun is actually an occultation. Slightly more annular eclipses than total eclipses occur, because on average the Moon lies too far away from Earth to cover the Sun completely. Hence the term annular eclipse.

In that case, at the time of greatest eclipse there remains a thin annulus (or ring) of brilliant Sun left uncovered. When a solar eclipse occurs when the Moon is at or near apogee, however, it appears smaller, and it cannot cover the Sun completely. When a solar eclipse occurs when the Moon is at or near perigee, it appears large enough to cover the bright disk, or photosphere, of the Sun completely, and a total eclipse occurs. The furthest point in the orbit is referred to as apogee, and the closest point is called perigee.

Because the Moon's orbit around Earth is an ellipse rather than a circle, however, at some times during the month the Moon is further away, and at other times it is closer to Earth, than average. As seen from Earth, therefore, the Sun and the Moon appear to be about the same size in the sky - about 1/2 of a degree in angular measure. One of the most remarkable co-incidences in nature is that (i) the Sun lies about 400 times as far from Earth as does the Moon, and (ii) the Sun is also about 400 times the diameter of the Moon. The reason why some solar eclipses are total and others are annular has to do with the elliptical nature of the Moon's orbit around Earth.

There are four types of solar eclipses:. . A total solar eclipse is considered by many to be the most spectacular natural phenomenon that one can observe. This configuration can only occur at New Moon, when the Sun and Moon are in conjunction, as seen from Earth.

A solar eclipse occurs when the Moon passes in front of the Sun and obscures it totally or partially. February 16, 1980: Launch of rockets from San Marco platform. February 26, 1979: Launch of rockets from Red Lake, Canada. November 12, 1966: Launch of two Titus-rockets fom Las Palmas, Argentina.

May 20, 1966: Launch of rockets at Karystos, Greece to watch the solar eclipse. May 30, 1965: Launch of rockets at Charlestown, USA. MacRobert, Sky & Telescope magazine. How to Watch a Partial Solar Eclipse Safely, Alan M.

Eye Safety During Solar Eclipses, Fred Espenak, NASA Goddard Space Flight Center. However, some eclipses can only be seen as a partial eclipse, because the central line never intersects the Earth's surface. This phenomenon can usually be seen from a large part of the Earth outside of the track of a central eclipse. A partial eclipse occurs when the Sun and Moon are not exactly in line, and the Moon only partially obscures the Sun.

The generic term for a total, annular or hybrid eclipse is a central eclipse. At some points on the Earth it is visible as a total eclipse; whereas at others it is annular. A hybrid eclipse is intermediate between a total and annular eclipse. Hence the Sun appears as a very bright ring surrounding the outline of the Moon.

An annular eclipse occurs when the Sun and Moon are exactly in line, but the apparent size of the Moon is smaller than that of the Sun. During any one eclipse, a total eclipse is visible only from a fairly narrow track on the surface of the Earth. The intensely bright disk of the Sun is replaced by the dark outline of the Moon, and the much fainter corona is visible (see image right). A total eclipse occurs when the Sun is completely obscured by the Moon.