Dioxins
Dioxins are extremely toxic chemicals that cause a range of health effects at levels hundreds or thousands of times lower than most chemicals. According to the US Environmental Protection Agency, even average background levels in the environment can cause adverse health effects in the general population. Dioxin is a carcinogen and has been linked to birth defects, hormone disruption, diabetes, learning disorders, behavioral problems, reproductive difficulties, diabetes, cardiovascular disease, and problems of the immune, nervous and gastrointestinal systems [1].
Dioxins do not occur naturally; they form when chlorine combines with organic matter at high temperature. Dioxins are a byproduct of many kinds of manufacturing, including paper bleaching and cement making. Dioxin is also produced by burning trash that contains the plastic polyvinyl chloride (PVC). In addition, when a product that contains certain brominated flame retardants burns, it creates dioxin.
Although dioxins are emitted into the air and find their way to our waters, very few people are exposed to dioxins via air or water. Instead, people are exposed to dioxins primarily by eating beef and other animals high on the food chain. Air emissions of dioxin settle out on grasses eaten by farm animals or in sediments that are eaten by fish. The dioxin builds up in fatty tissues and is passed on to humans. Beef, pork, fish, shellfish, dairy products, and human milk are the major sources of human exposure. Burn barrels, usually located close to the ground, tend to localize the dispersion of dioxin emissions, putting people who eat locally produced food at greater risk for dioxin exposure.
Dioxins can cross the placenta, exposing children prenatally. In addition, newborns can be exposed through breast milk.
The Willamette and Columbia rivers have levels of dioxin above the Total Maximum Daily Load (TMDL) pollutant limits established by the Oregon Department of Environmental Quality (DEQ). According to DEQ, a total of 463 miles of Oregon’s rivers and streams do not meet minimum safety standards for fish consumption due to dioxins.
DEQ estimates that over 100 pounds of dioxin are released into Oregon’s air and water annually. According to DEQ’s 1999 air emissions inventory, the two main sources responsible for 96% of airborne dioxin emissions in Oregon are some 200 wood-fired boilers used primarily by the pulp and paper industry (49%) and burning of residential garbage (47%). Backyard burning of residential garbage is still a common practice in many areas of the state. While burning of plastics is banned in Oregon, DEQ estimates that when backyard burning is permitted, a certain amount of plastics is still being burned.
Emissions of dioxin to water in Oregon come primarily from lumber and pulp and paper manufacturing, specifically the use of the chemical pentachlorophenol (which contains dioxin) in the wood treatment process. Regulatory agencies are failing to control most point sources of dioxin. Of the 20 facilities that reported releasing dioxin releases to the air and/or water in 2001, only one held a permit from DEQ for its release of dioxin.
Public policy solutions that will protect us all:
* Provide local alternatives to backyard trash burning and burn barrels. Where garbage collection services do not exist, municipalities should provide incentives for recycling and composting to eliminate the need for backyard trash burning.
* Ban all backyard burning or, at a minimum, enforce the law on burning plastic household waste and provide more alternatives to burning, especially in rural areas.
* Require wood-fired boilers to reduce dioxin emissions. The Oregon Environmental Council worked on a project to help make boilers in Oregon more efficient [PDF] which had the added benefit of helping to reduce their dioxin emissions.
* Include dioxin limits in all air and water permits for facilities that release dioxin.
* Fully implement Oregon’s executive order phasing out the discharge of persistent bioaccumulative toxins in Oregon by 2020.
What you can do to protect yourself:
* Don’t burn your trash, especially plastics.
* Eat low on the food chain.
* Avoid buying products made of PVC.
* Check to make sure that the fish you catch to eat is not on Oregon’s fish consumption advisory list.
Some methods of waste disposal release air pollutants and greenhouse gases into the atmosphere. Waste recycling offers one means of reducing the impacts of waste disposal on the atmosphere, but there are other methods of waste disposal which are more environmentally friendly.
The most common disposal methods, particularly in the UK, are landfill and to a lesser extent incineration. Each year approximately 111 million tonnes of controlled waste (household, commercial and industrial waste) are disposed of in landfill sites in the UK. Some waste from sewage sludge is also placed in landfill sites, along with waste from mining and quarrying. There are over 4000 landfill sites in the UK. As landfill waste decomposes, methane is released in considerable quantities. Currently it is estimated that over 1.5 million tonnes of methane are released by landfill sites in the UK each year. Methane is a strong greenhouse gas and contributes to global warming. Furthermore, the leachate fluids formed from decomposing waste can permeate through the underlying and surrounding geological strata, polluting groundwater which may be used for drinking water supplies. Containment landfills however, can limit the spread of this waste leachate.
Incineration is the second largest waste disposal method in most countries. In the UK, approximately 5% of household waste, 7.5% of commercial waste, and 2% of industrial waste is disposed of by incineration. When burning waste, a large amount of energy, carbon dioxide and other potentially hazardous air pollutants is given off. Modern incinerators however, can use this waste energy to generate electricity and hence prevent the energy from being wasted. Incineration plants range from large scale, mass-burn, and municipal waste incinerators to smaller clinical waste incinerators used in hospitals. During the 1990s many UK hospital incinerators were forced to close owing to tougher emissions legislation introduced by the 1990 Environmental Protection Act. Today, hospitals tend to share one large incinerator to dispose of the wastes for a number of hospitals.
A less common but more sustainable method of waste disposal is anaerobic digestion. In this process waste decomposes in an enclosed chamber, unlike in a landfill site. Digestion takes place in an oxygen-free environment. Bacteria thrive in this environment by using the oxygen that is chemically combined within the waste. They decompose waste by breaking down the molecules to form gaseous by-products (methane) and small quantities of solid residue. Anaerobic sewage plants produce significant quantities of methane, which can be burnt to generate electricity. Liquid and solid organic fertilisers are also formed, and can be sold to cover operating costs. For several years, sewage sludge and agricultural waste has been treated by anaerobic digestion, and the process is now being used for municipal solid waste. It requires the biodegradable section of the waste to be separated from other material and put into digestion chambers. Currently, the UK has only a small number of plants, and each can handle only a few hundred tonnes of waste each year. However, the usage of anaerobic digestion as a sustainable waste disposal method is forecast to increase. Many other countries already utilise anaerobic digestion to dispose of large amounts of waste. Denmark for example, treats 1.1 million tonnes of waste by anaerobic digestion every year.
As well as recycling waste, individuals can adopt more sustainable ways of disposing it. One way is to compost any organic waste such as food and garden waste. Organic waste breaks down over a few weeks into a mulch which can be used as a soil fertiliser. Individual households have practiced small-scale composting for many years, and the UK Government is now encouraging this on a wider scale. Large-scale composting schemes are also being developed, with the collection of organic waste from parks and civic amenity sites. Garden and food wastes are collected directly from households in separate kerbside collections. Large central facilities can then compost the collected organic waste. These schemes are to help the UK meet its target of recycling and composting 33% of household waste by 2015.
Dioxan
1,4-Dioxane is often called dioxane. It is a clear, colorless heterocyclic organic compound which is a liquid at room temperature and pressure and has the molecular formula C4H8O2 and a boiling point of 101 °C. Dioxan is commonly used as a solvent. 1,4-Dioxane has a weak smell similar to that of diethyl ether. There are also two other less common isomeric compounds, 1,2-dioxane and 1,3-dioxane. 1,2-Dioxane is a peroxide which forms naturally in old bottles of tetrahydrofuran.
Dioxan is classified as an ether, with each of its two oxygen atoms forming an ether functional group. It is more polar than diethyl ether, which also has four carbons, but only one ether functional group. Diethyl ether is rather insoluble in water, but 1,4-dioxane is miscible with water and is hygroscopic. Dioxan’s higher polarity and slightly higher molecular mass also gives it a substantially higher boiling point than diethyl ether.
When used as a solvent for a Grignard reaction, Dioxane promotes the formation of magnesium halide salts in the Schlenk equilibrium. The name dioxane should not be confused with dioxin, which is a different compound but is also a diether (two ether functional groups).
Dioxan is primarily used in solvent applications for the manufacturing sector and it is also found in fumigants and automotive coolant. Also the chemical is used as a foaming agent and appears as an accidental byproduct of the ethoxylation process in cosmetics manufacturing. Dioxane may contaminate cosmetics and personal care products such as deodorants, shampoos, toothpastes and mouthwashes.
Dioxan is also commonly used as an internal standard for calibrating chemical shifts in NMR, as tetramethylsilane which is the compound by which all chemical shifts are referenced and is not soluble in D2O.
Dioxanes combine with atmospheric oxygen on standing to form explosive peroxides, similar to many other ethers. Distillation of dioxanes concentrates these peroxides increasing the danger and appropriate precautions should be taken.
Dioxan is a known eye and respiratory tract irritant. It is suspected of causing damage to the central nervous system, liver and kidneys. Accidental worker exposure to 1,4-dioxane has resulted in several deaths.
Dioxane is classified by the IARC as a Group 2B carcinogen: possibly carcinogenic to humans because it is a known carcinogen in animals. The State of California, under proposition 65, listed 1,4-dioxane as a chemical known to cause cancer on January 1, 1988.
As with many solvents, 1,4-dioxane forms contamination plumes in groundwater when released to the environment and sadly, groundwater supplies have been adversely impacted in several areas.
Dioxane is highly soluble in groundwater, does not readily bind to soils, and readily leaches to groundwater. Dioxan is also resistant to naturally occurring biodegradation processes. Due to these properties, a 1,4-dioxane plume is often much larger and further downgradient than the associated solvent plume.
Health Effects
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Danger! Dioxan tends to form explosive peroxides, especially when anhydrous. Flammable liquid and vapor. Harmful if swallowed, inhaled or absorbed through skin. Dioxan affects central nervous system, liver and kidneys. Causes irritation to skin, eyes and respiratory tract. Possible cancer hazard. May cause cancer based on animal data. Risk of cancer depends on duration and level of exposure.
Dioxan Inhalation:
Dioxan is highly toxic by inhalation. Easily absorbed through lungs. Symptoms include irritation of the respiratory tract, headache, nausea, vomiting, dizziness, and narcosis. Can cause liver damage and brain and lung edema. Death may occur from kidney failure. Dioxane poisoning has poor warning properties.
Dioxan Eye Contact:
Vapors cause eye irritation. Splashes cause severe irritation, possible corneal burns and eye damage.
Chronic Exposure:
Prolonged exposure may cause central nervous system depression, loss of appetite, nausea, abdominal tenderness, and liver or kidney damage. Prolonged skin contact may cause dermatitis. Suspected human carcinogen based on animal data. Repeated inhalation exposures to low concentrations have been fatal.
Ingestion:
Causes sore throat, abdominal pain. Other symptoms parallel those from inhalation.
Skin Contact:
Causes irritation to skin. Symptoms include redness, itching, and pain. May be absorbed through the skin with possible systemic effects.
Aggravation of Pre-existing Conditions:
Persons with pre-existing skin disorders or eye problems, or impaired liver, kidney or respiratory function may be more susceptible to the effects of the substance.
First Aid Steps
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Dioxan Inhalation:
Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Call a physician.
Dioxan Ingestion:
Induce vomiting immediately as directed by medical personnel. Never give anything by mouth to an unconscious person. Call a physician.
Skin Contact:
In case of Dioxan contact, immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Call a physician.
Dioxan Eye Contact:
Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately.
Environmental and Ecological Information:
When released into the soil, Dioxan is not expected to biodegrade. When released into the soil, this material may leach into groundwater. When released into the soil, this material may evaporate to a moderate extent. When released into water, Dioxan is not expected to biodegrade. When released into water, this material may evaporate to a moderate extent. This material has a log octanol-water partition coefficient of less than 3.0.
This material is not expected to be toxic to aquatic life. The LC50/96-hour values for fish are over 100 mg/l.
This material is not expected to significantly bioaccumulate. When released into the air, Dioxan is expected to be readily degraded by reaction with photochemically produced hydroxyl radicals. When released into the air, this material is expected to have a half-life of less than 1 day.
Protect against physical damage. Store in a cool, dry well-ventilated location, away from direct sunlight and any area where the fire hazard may be acute. Store in tightly closed containers (preferably under nitrogen atmosphere). Outside or detached storage is preferred. Inside storage should be in a standard flammable liquids storage room or cabinet. Separate from oxidizing materials. Containers should be bonded and grounded for transfers to avoid static sparks. Storage and use areas should be No Smoking areas. Use non-sparking type tools and equipment.
Protect from freezing. Before using bulk quantities of this material, test for presence of explosive peroxides. Wear special protective equipment (Sec. 
for maintenance break-in or where exposures may exceed established exposure levels. Wash hands, face, forearms and neck when exiting restricted areas. Shower, dispose of outer clothing, change to clean garments at the end of the day. Avoid cross-contamination of street clothes. Wash hands before eating and do not eat, drink, or smoke in workplace. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product.
Ventilate area of leak or spill. Remove all sources of ignition. Wear appropriate personal protective equipment as specified in Section 8. Isolate hazard area. Keep unnecessary and unprotected personnel from entering. Contain and recover liquid when possible. Use non-sparking tools and equipment. Collect liquid in an appropriate container or absorb with an inert material (e. g., vermiculite, dry sand, earth), and place in a chemical waste container.
Do not use combustible materials, such as saw dust. Do not flush to sewer! If a leak or spill has not ignited, use water spray to disperse the vapors, to protect personnel attempting to stop leak, and to flush spills away from exposures. US Regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities. The toll free number for the US Coast Guard National Response Center is (800) 424-8802.