Revised Assignment 1: Vinyl Chloride by Team Delta

Vinyl Chloride – A Brief Introduction to a Dangerous Chemical

By Team Delta
David Seidel Daniel South Doug Sposito
Mary Steffen-Deaton Stacey Stephenson Kandy VanMeeteren

Rob Walker Damien Watt


General Chemistry and Use
by Damien Watt


Vinyl chloride is the organic compound with the formula CH2:CHCl. It burns easily and it is not stable at high temperatures. It is a manufactured substance that does not occur naturally. It can be produced when other substances such as trichloroethane, trichloroethylene, and tetrachloroethylene are broken down. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC). Vinyl chloride was first produced in 1835 by Justus von Liebig and his student Henri Victor Regnault. They obtained it by treating ethylene dichloride with a solution of potassium hydroxide in ethanol (Vinyl Chloride, 2006).

Vinyl chloride, also known as chloroethene, is a halogenated aliphatic hydrocarbon with an empirical formula of C2H3Cl and a molecular weight of 62.5. It is a colorless gas with a mild sweetish odor, a melting point of -153.71 °C, a boiling point of -13.8°C, a specific gravity of 0.9121 g/mL, and a vapor pressure of 2580 torr. The odor threshold for vinyl chloride is 3,000 ppm. Vinyl chloride is slightly soluble in water and is quite flammable. The vapor pressure for vinyl chloride is 2,600 mm Hg at 25 °C, and it has a log octanol/water partition coefficient (log Kow) of 1.36 (Vinyl Chloride, 2006).

Production
Two methods that are used in the commercial production of vinyl chloride are the
hydrochlorination of acetylene and the dehydrochlorination of dichloroethylene processes.

Production from Ethylene dichloride
The production of vinyl chloride from ethylene dichloride (EDC) consists of a series of well defined steps. Ethylene dichloride (EDC) is prepared by reacting ethylene and chlorine (About Vinyl and PVC, 2008). In the presence of iron (III) chloride as a catalyst, these compounds react exothermically:

CH2=CH2 + Cl2 → ClCH2CH2Cl

When heated to 500°C at 15–30 atm (1.5 to 3 MPa) pressure, EDC decomposes to produce vinyl chloride and HCl:

ClCH2CH2Cl → CH2=CHCl + HCl

A refrigerant is then used to chill the outlet stream prior to a series of distillation towers (About Vinyl and PVC, 2008). The last distillation tower has pure HCl going from the top and product vinyl chloride coming out of the bottom. The recycled HCl is used to produce more EDC. The recycling process involves a copper (II) chloride-catalyzed oxychlorination of ethylene. Oxychlorination entails the combined action of oxygen and hydrogen chloride to produce chlorine in situ:

CH2=CH2 + 2 HCl + ½ O2 → ClCH2CH2Cl + H2O

Due to the economical advantages of this recycling as well as the low cost of ethylene, most vinyl chloride has been produced via this technique since the late 1950s. (David Allen, 2009)

Production from Acetylene
Acetylene, produced by the hydrolysis of calcium carbide, is treated with hydrogen chloride to give vinyl chloride:

C2H2 + HCl → CH2=CHCl

The method is not widely practiced in the west due to the cost of the acetylene and the associated environmental impact of its production. (David Allen, 2009)

References:

David Allen. (2009, April 3). Industrial Ecology. [Green Engineering]. Retrieved April 3, 2009, from
http://www.epa.gov/opptintr/greenengineering/pubs/ch14_summary.html: Allen, David, Environmental Protection
Agency

Vinyl Chloride. (2006, July). Retrieved April 3, 2009, from http://www.atsdr.cdc.gov/toxprofiles/tp20-c2.pdf: Center for Disease Control

About Vinyl and PVC. (2008, April). Retrieved April 7, 2009, from
http://www.vinylbydesign.com/site/page.asp?CID=1&DID=2: Vinyl in Design


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The Metabolism of Vinyl Chloride
By Doug Sposito

The main route of human metabolism of vinyl chloride (VC) is in the liver by cytochrome P450 enzymes. The most common reaction is a monooxygenase reaction that inserts one atom of oxygen into the vinyl substrate while the other oxygen atom is reduced to water[i].
This metabolism of VC proceeds with oxidation to an intermediate compound chlorooxirane. The chlorooxirane degrades further into other molecules such as formic acid and oxyglycolic acid which in turn, are transformed to CO2 and H2O[ii]. The authors proposed mechanism of intracellular aerobic metabolism of VC is illustrated in Figure 1.
The oxidative detoxification of VC occurs primarily in the liver which then can be bound to glutathione or cysteine and excreted in the urine with no significant accumulation of vinyl chloride in the system[iii].

Previous studies had thought ethanol would inhibit the human metabolism of VC[iv] but recent studies have shown this not to be likely[v]. From studies of its metabolism in rats VC is estimated to have a biological half-life of 20 minutes[vi].
[1] Benjamin L. Van Duuran “Chemical Structure, reactivity and carcinogenicity of Halohydrocarbons”, , Environmental Health Perspectives, Vol 21 1977
[1] “Remediation of Vinyl Chloride” ORC Technical Bulletin 2.2.2.3 Oxygen Release Compound http://www.regenesis.com/library/Technical%20Bulletins/ORC/ORC%20Technical%20Bulletin%202.2.2.3.pdf
[1] Green, T. & Hathway, D.E. “The chemistry and biogenesis of the S-containing
metabolites of vinyl chloride in rats”. Chemico-biological interactions, 17: 137-150
(1977).
[1] D Hultmark, et al “Ethanol inhibition of vinyl chloride metabolism in isolated rat hepatocytes”
Chemico-biological interactions 01/05/1979; 25(1):1-6.



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Vinyl Chloride Toxic Effects
By Mary Steffen-Deaton

“Vinyl chloride is a sweet smelling, colourless gas at room temperature” (Environment Australia, 2001). It is used commonly in our society in the production of PVC (polyvinyl chloride). The emissions of vinyl chloride enter into the environment, generally, by two sources: air and water. Air emissions are the largest portion of emissions of vinyl chloride. The emissions of vinyl chloride, entering into the water supply and contaminating wells, are much smaller than that of air emissions. Studies have shown us that vinyl chloride is a toxic chemical for humans and the environment. Vinyl chloride is not a naturally occurring chemical but seeps into the environment through several sources like from the chemical industry, plastics industry, wastes in landfills, and treated wastewater (Environment Australia, 2001). The EPA classifies vinyl chloride as a carcinogen (EPA, 1992). It is recommended to avoid human exposure to vinyl chloride. Some of the major health effects possible from vinyl chloride exposure are cancer, liver disease, lymphoma, Acroosteolysis, Raynaud's syndrome and leukemia.

How do you get exposed to Vinyl Chloride?
A person can get exposed to vinyl chloride through inhalation, touching or ingestion. Most ingestion exposure generally occurs through drinking or cooking with water from a contaminated well. Inhalation exposure can come from several sources. Breathing vinyl chloride at a contaminated work place or breathing air from a leaking landfill or the plastics industry are some examples (Ohio Department of Health, 2003). Also cigarettes with tobacco contain low levels of vinyl chloride so avoid breathing second hand smoke is recommended (ATSDR, 2006). Touching or skin exposure can occur in industry.

Toxic Effects from Exposure to Vinyl Chloride:

What toxic effects occur depends on several factors:

- the length of exposure to the vinyl chloride
- the amount of exposure
- how the vinyl chloride entered into the body (inhaled, touched, or eaten).

Acute exposure to high levels of vinyl chloride by inhalation has effects on the Central Nervous System (CNS), such as sleepiness, dizziness, drowsiness, and headaches (EPA, 1992). Vinyl chloride is slightly irritating to the eyes and respiratory tract in humans also.
Chronic effects of exposure to vinyl chloride can result in liver damage, immune reactions, nerve damage, blood cancer, and liver cancer. The long term effects to exposure to high levels of vinyl chloride result in decrease in bone strength in fingers, arms, and joints as well as blood flow problems (Ohio Department of Health, 2003).


References:
Environment Australia, 2001 Air toxics and indoor air quality in Australia. State of knowledge report. ISBN 0 6425 4739 4 from: http://www.environment.gov.au/atmosphere/airquality/publications/sok/vinyl.html
EPA Hazard Summary-Vinyl Chloride: Created in April 1992; Revised in January 2000 from: http://www.epa.gov/ttn/atw/hlthef/vinylchl.html
Agency for Toxic Substances and Disease Registry (ATSDR). 2006. Toxicological Profile for Vinyl Chloride. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service. From: http://www.atsdr.cdc.gov/tfacts20.html#bookmark05
Ohio Department of Health: Health Assessment Section Vinyl Chloride, 2003. From:
http://www.odh.ohio.gov/ASSETS/B5689E862EAB4FD89846F63EB9ACBE04/vinlchl.pdf

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Health issues with Vinyl Chloride
by Kandy Van Meeteren

Health issues for selected occupations would include persons that work with polyvinyl resins, rubber and organic chemicals. These people are the most affected by inhalation, dermal, indigestive, and absorption, known as routes of entry. These routes of entry have acute effect meaning one or a couple of times exposed or chronic exposure would lead to a small or large amount on a daily or weekly exposure.

Inhalation involves air borne contaminants or a gas under ambient conditions, that is taken into the body through the lungs. After entry in the lungs, the conditions can accelerate depending how fast the vinyl chloride gas can enter the bloodstream, and reach to the brain and other organs. Vinyl chloride inhalation can cause damage to the central nervous system, that may appear to be like alcohol poisoning. Other affects are lightheadness, nausea and dulling of the visual and auditory responses may develop from acute exposures. Severe vinyl chloride exposure could cause death.

Adsorption and dermal through the skin or the eyes can occur quite rapidly in cuts or abrasions on the skin. The eyes may be attack instantly and with severely irritated. There is a potent skin irritant with a damaging case of frostbite if the chemical comes in contact with the outside dermal layer. Also, dermatitis, and acro- osteolysis occurs from being exposed at a chronic level. "Definition of acro-osteolyis is destruction of the digit tips, including the bone, usually caused by vasospasm. It is characterized by Raynaud's phenomenon, loss of bone tissue in the hands, and sensitivity to cold temperatures. Causes include scleroderma, Raynaud's disease, Buerger's disease, frostbite, and exposure to vinyl chloride. " (Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier). Chronic exposure may damage the liver and cause a specific kind of liver cancer called angiosacrcoma. Reports and experimental evidence have shown that links vinyl chloride to cancer of the lung, lymphatic, and tumors in brain regions, liver, kidney, and fibrosis in the connective tissue.

Ingestion in the workplace is caused by workers unknowingly eating, drinking, or smoking harmful chemicals still on hands, uniforms, and surfaces that were used in the work station. Most of ingestion entry is cross contamination with air bourne chemicals.

In 1974, OSHA set better standards for workers in the workplace with vinyl chloride. OSHA announced that that vinyl chloride was a substance known to be a carcinogenic. The standard of one ppm PEL for a eight hour day.

References:
Principles of Toxicology: environmental and industrial application/edited Phillip L. Williams, Robert C. James, Stephen M. Roberts. 2nd ed. page 397.

Fundamentals of industrial hygiene/edited Barbara A. Plog, Patricia J. Quinlan. 5th ed. pages 21,60, 681, 838. 840.

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Federal Regulations of Vinyl Chloride
By Stacy Stephenson


According to the International Agency for Research on Cancer (IARC), vinyl chloride is classified as a Group 1 carcinogen mostly affecting the liver. (http://www.inchem.org/documents/iarc/suppl7/vinylchloride.html) and there is no level of exposure at which there are no possible health effects (http://www.articlecbase.com/health-articles/vinylchloride-classified-as-carcinogen-508930.html). These findings support the federal regulation of vinyl chloride in such everyday things as food, water and air.

In 1974, Congress passed the Safe Drinking Water Act (SDWA) which required the Environmental Protection Agency (EPA) to set safe levels of contaminants in water. The result was the Maximum Contaminant Level Goals (MCLG) which the EPA set at zero for vinyl chloride. Since these are non-enforceable limits they were tasks with developing the Maximum Contaminant Level (MCL) which are enforceable by law. The MCL for vinyl chloride is 2ppbm and should not be exceeded at any time. The EPA set this limit because it is the lowest level that is possible to reasonably reach based on the technology and the resources that are available today. The National Primary Drinking Water Regulations is the body of legislation responsible for ensuring that the MCLs are met in all public water supplies
(http://www.epa.gov/OGWDW/contaminants/dw_contamfs/vinylchl.html).

Since vinyl chloride can contaminate food, careful consideration must be given to the type of container used to store and transport foods. Given that the compositions of foods vary greatly, not all foods would be contaminated at the same levels. It is for this reason that there are no specific guidelines for the overall plastic containers and/or carriers containing vinyl chloride. Each must be handled on a “case by case” basis from the FDA (Toxicological Profile for Vinyl Chloride (http://www.atsdr.cdc.gov/lfacts20.html#bookmark10). Products (drug and cosmetic) in the form of aerosols containing vinyl chloride have also been a problem in the past. They have since been pulled from the market and they are no longer allowed to be used in the production of aerosol products (http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s186viny.pdf).

Given that vinyl chloride is a Hazardous Air Pollutant (HAP) it also regulated by the Clean Air Act (CAA) under NESHAPS (National Emission Standard for Hazardous Air Pollutants) and NSPS (New Source Performance Standards). These are standards adopted by the EPA to regulate air emissions from industries (http://www.cdphe.state.co.us/ap/nsps.html#nspsoverview).

In addition to the above mentioned regulations, vinyl chloride is also regulated under RCRA as a hazardous constituent and hazardous waste, Superfund as a hazardous substance, Clean Water Act as a priority pollutant, under the Toxic Release Inventory as a reportable chemical (http://www.scorecard.org/chemical-profiles/regulation) and under The Emergency Planning and Community Right-to-know Act of 1986. The release of more than 1 pound into the air, water or land must be reported to the EPA. It is also regulated under the Department of Transportation (DOT) as a hazardous material (http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s186viny.pdf).

As far as the workplace is concerned, vinyl chloride is regulated by OSHA under 1910.1200- Hazard Communication Standard. They place a PEL (permissible exposure limit) on vinyl chloride which is the regulatory limits of the concentration of a substance in air and is based on an 8 hour time weighted average (TWA) work shift unless otherwise stated. Another standard if measurement is the action level which is the regulatory limit set at one half the PEL but can vary. The PEL for vinyl chloride is 1ppm TW and 0.5ppm action level. Vinyl chloride also has an Threshold Limit Value (TLV) that is set forth by the American Conference of Governmental Industrial hygienists (ACGIH) which is not a standards but an opinion of a safe worker level. It is 1ppm TWA (http://www.mathesongas.com/pdfs.msds). This happens to agree with OSHA’s level but this isn’t always the case.

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Vinyl Chloride Contaminated Sites

David J. Seidel

Introduction
Vinyl chloride has been found in at least 133 of 1177 hazardous waste sites on the National Priorities List (NPL) in the U.S.
National Priorities List (NPL) Sites
The following NPL sites descriptions are representative of the 133 sites that have been contaminated with vinyl chloride:

1. New Carlisle Landfill, Clark County, Ohio
The New Carlisle Landfill is an unlined landfill that encompasses between approximately 12 to 21 acres. It served as a general refuse and solid waste landfill from the mid-1950s until the early 1970s. During its operation, it received industrial, commercial and residential waste. After several years of inactivity, the landfill was officially closed in 1977. It was covered with two to four feet of clay. In 1997, Ohio EPA discovered vinyl chloride above the safe drinking water standard in a landfill monitoring well. Contamination of groundwater with volatile organic compounds including trichloroethene (TCE), tetrachloroethene and vinyl chlorides was detected below the landfill and in a plume located south of the landfill.Two public wells and two residential wells were found to be contaminated above the safe drinking water level with vinyl chloride The vinyl chloride groundwater contamination could potentially affect approximately 15 residential wells within one-half mile radius of the landfill.EPA placed this site on the NPL because vinyl chloride was detected at levels above the safe drinking water standard in three wells, and because of the potential threat the site poses to other residential wells in the area.

2. Operating Industries, Inc. Landfill, Monterey Park, California
Operating Industries, Inc., operated a landfill on 190 acres in the City of Monterey Park, California. The 45-acre northern section was separated in the 1960s from the southern 145-acre section by the Pomona Freeway. The original landfill included at least a portion of both sections. From 1948 to 1983, solid and liquid wastes, some hazardous, were disposed of at the site.
Landfill generated leachate contained vinyl chloride, benzene-type compounds, tetrachloroethylene, heavy metals, and other contaminants, according to testing by the company. In July 1983, vinyl chloride above ambient standards was detected in air at and around the landfill, which is adjacent to a large residential area.

EPA collected samples from 16 subsurface probes in an adjacent housing development. Some samples confirmed the presence of methane and vinyl chloride in subsurface soils. Interior home samples collected in November 1984 had low levels of methane and nondetectable levels of vinyl chloride. in October 1985 elevated levels of methane and vinyl chloride were also detected in a home adjacent to the landfill.

3. Cayuga County Ground Water Contamination, New York
The Cayuga County Ground Water Contamination site consists of a plume of contaminated ground water from unknown sources. The site is located, in a rural area of Cayuga County, is in an area of residential properties mixed in with extensive farmland.
Sampling results by EPA determined that 51 residential wells are contaminated with volatile organic compounds (VOCs), primarily vinyl chloride, trichloroethylene (TCE) and cis-1,2,dichloroethylene (cis-1,2,DCE), in concentrations above the Federal maximum contaminant levels (MCLs). Of these drinking water supply wells twenty-four were found to be contaminated above EPA's Removal Action Levels (RALs) for vinyl chloride and/or cis-1, 1,DCE of two parts per billion (ppb) and 400 ppb, respectively. The plume is about 3,050 acres in area and about 120 homes are within its boundaries.
During an April 2001, sampling event, an observed release of vinyl chloride, TCE and cis-1,2 DCE was documented by chemical analysis of ground water samples collected from private wells.
4. Brio/Dixie Refining Site , Texas
The Brio and Dixie Oil Refining Site is located near the city of Friendswood, Texas. From 1957 and 1982, by-product recycling, copper catalyst regeneration, petrochemical recovery, and jet fuel processing operation were conducted at the site. Contaminants found include styrene tars, vinyl chloride, chlorinated solvent residues, metallic catalyst, and fuel oil residues. The site, which occupies about 58 acres, drains to a tributary feeding Clear Creek.
Due to a class action suit, a nearby subdivision was bought out and demolition of the homes took place. Parties agreed upon the creation of 6 acres of freshwater riparian wetland habitat adjacent to Mud Gully in Harris County and the preservation of 100 acres of mature mixed forest with a 19 acre pasture buffer zone. This habitat creation and acquisition served to compensate the public for injuries to natural resources. The total settlement value at this site is worth over $1.2 million.
A Restoration Plan and Environmental Assessment for this site were completed in December 2003 and a Consent Decree was signed on January 2006. The entire restoration site is protected in perpetuity through a Conservation Easement held by the Legacy Land Trust.

5. Berks Landfill, Pennsylvania
The Berks Landfill Superfund Site is located in, Berks County, Pennsylvania. The site consists of two closed landfills: a 49-acre eastern landfill and a 19-acre western landfill. Historically an iron ore mine, from the 1950s to the 1980s, the landfill operated as a municipal landfill. In 1975, a permit was granted to the landfill by the state to discharge leachate from its collection system into an adjacent stream. Additionally, in 1975, the eastern landfill was granted a solid waste permit to accept municipal refuse and demolition refuse. In 1986 landfill operations ended and the landfills were closed with a soil cap. In the 1980's sampling of on-site monitoring wells discovered the groundwater was contaminated with volatile organic compounds (VOCs) and metals. VOCs included vinyl chloride, trichloroethene, and cis-1,2-dichloroethene and metals include aluminum, iron, and manganese. The groundwater on-site was determined to pose a threat to human health if it was consumed.

EPA selected a remedy to repair the eastern landfill cap in 1997; and to continue operation of the existing leachate collection system; to perform long-term sampling and monitoring of a sentinel well, residential wells, on-site wells, landfill gas, and the creek; and to implement institutional controls to prevent future consumption of on-site groundwater and to restrict development on-site.

The leachate collection lines and manholes were cleaned, inspected, and repaired and the three leachate collection ponds were re-shaped and re-lined for an approximate volume of 1.5 million gallons, in 2000. The leachate is pumped to the local wastewater treatment plant. In order to monitor the site, gas monitoring probes and a groundwater monitoring well were installed. Additionally, to improve a wetland area on-site, 300 trees were planted.

The groundwater will continue to be monitored with on-site wells and gas probes, residential wells, and the sentinel well. In March 2008 EPA prepared a final close-out report on the clean-up activities that documented that the cleanup objectives had been met. The Berks Landfill site was officially removed from the National Priorities List in November 2008. EPA will continue to oversee the operation and maintenance at the site. EPA will perform a five-year review in 2010.
References:
1. http://wvlc.uwaterloo.ca/biology447/Assignments/assignment1/vinyl_chloride/vinyl_chloride1.htm, last accessed on Friday, September 18, 2009
2. http://www.epa.gov/superfund/sites/npl/nar1787.html, last accessed on Friday, September 18, 2009
3. http://www.epa.gov/superfund/sites/npl/nar932.html, last accessed on Friday, September 18, 2009
4. http://www.epa.gov/cgi-bin/epaprintonly.cgi, last accessed on Friday, September 18, 2009
5. http://www.fws.gov/southwest/es/contaminants/NRDAR/SiteInformation/Texas/BrioDixie.pdf
last accessed on Friday, September 19, 2009
6. http://www.epa.gov/reg3hscd/npl/PAD000651810.htm, last accessed on Friday, September 19, 2009


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Remediation of Vinyl Chloride Contamination
By Daniel South

Groundwater:
Groundwater contaminated by vinyl chloride can be treated in two ways: ex-situ and in-situ. The decision to use ex-situ or in-situ will be determined by the unique characteristics of the site and the preferences of the people making the decisions.

Ex-Situ Remediation
For ex-situ (meaning “external to the System” (Pichtel, 2007, page 416)) treatment of vinyl chloride, the water is pumped out of the ground and sent to a treatment plant (Pichtel, 2007). The water is then treated by running it through activated carbon that causes the pollutants to adsorb onto the carbon. Frequently there is an air stripper as well. An air stripper usually is a column filled with plastic or steel balls so that there is a large amount of surface area. The contaminated water trickles down the balls, exposing it to the atmosphere (Author’s personal observations and Pichtel, 2007). Volatile organic compounds, like vinyl chloride leave the water and go into a gaseous phase where they can either react with oxygen and break down or be sucked into the carbon filter. (Pichtel, 2007). Water leaving the treatment plant should have no contaminants and the water is either pumped back into the ground which requires an underground injection permit (EPA1, 2009)or it is discharged into surface drainage under a National Pollutant Discharge Elimination System (better known as NPDES) permit (EPA2, 2009).

In-Situ Remediation
For in-situ (meaning “in place” (Pichtel, 2007 page 418)) remediation, the primary method of remediation is to oxidize the contaminant and chemically change it to an end result of carbon dioxide and water (Wong and Bonsavage, 2001). The oxidation breaks the carbon-carbon double bond and replaces it with a carbon-oxygen double bond. The chlorine is removed to form hydrochloric acid as an intermediate compound before reacting to form other compounds. The vinyl chloride, C2H3Cl changes to CO2, H2O, and HCl (Wong and Bonsavage, 2001). This is done in two ways: direct chemical oxidation or bioremediation using aerobic micro-organisms.
A third in-situ treatment uses reductive dechlorination using anaerobic micro-organisms to convert the vinyl chloride into ethane and chloride ions.

Direct Chemical Oxidation
Direct chemical oxidation is performed by injecting a strong oxidizer such as concentrated hydrogen peroxide and ferrous iron (Fe2+), ozone, or one of the other commercially available products (Wong and Bonsavage, 2001). This method uses direct chemistry to destroy the vinyl chloride. One problem associated with this method is that the oxidizer reacts with other compounds as well as the intended contaminant. Enough oxidizer must be injected into the groundwater such that there is sufficient amount to cover the mass of contaminant in the water as well as enough to cover that lost to reactions with unintended materials such as organic roots, debris, and peat. Also, these reactions generate significant amounts of heat and pressure and can damage well casings and other buried objects (author’s direct observations). On the positive side, this treatment is relatively quick and the vinyl chloride can be destroyed more quickly than with other remediation methods (Wong and Bonsavage, 2001).


Bioremediation Using Aerobic Micro-organisms
Micro-organism using enzymes are able to carry out chemical reactions without the heat generated by direct chemical reaction (USGS, 2009). As such, there is less likelihood of damaging subsurface materials and it is a very effective method of remediation. It can be a much slower process than direct oxidation. The main goal is to create conditions that will promote the growth of colonies of the desired organisms. These organisms use the vinyl chloride as food and use the oxygen for respiration. Most environments already contain these organisms to some degree unless the environment is severely reducing or too harsh in other ways. This method injects a product that releases oxygen slowly into the groundwater. This can be a commercial product or simply dilute hydrogen peroxide (5-10% concentration). Depending on the size of the area to be remediated and the nature of the subsurface environment, it may take several injections over time to create the conditions you desire. Evidence that you are creating an aerobic environment would include an increase in dissolved oxygen content in the groundwater and an increase in levels of oxidation-reduction potential (ORP) which measures the relative reducing or oxidizing ability of the groundwater. These measurements are easily made at wells using commercially available meters (Author’s personal observations). Analysis of groundwater samples should show a decrease in vinyl chloride and an increase in carbon dioxide (USGS, 2009).

Bioremediation Using Anaerobic Micro-organisms
There can exist environments where it may be too difficult to create oxidizing conditions. Luckily, there are some microbes that can de-chlorinate the vinyl chloride under reducing conditions. The goal of dechlorination is to convert the vinyl chloride into ethene (also known as ethylene) by removing the chlorine. (USGS, 2009). The chlorine is converted into a chloride ion and usually forms a non-hazardous compound such as sodium chloride. For chlorinated solvents it is relatively easy to remove a chlorine atom from tetrachlorethene (C2Cl4) under reducing conditions. It is a bit harder to remove a chlorine atom from trichloroethene (C2HCl3) and harder still from cis-1,2-dichloroethene (C2H2Cl2) under these conditions (Author’s personal experience at a remediation site). With each step you need slightly stronger reducing conditions. With vinyl chloride it is hardest of all under reducing conditions, but it can be done. Again, the process is not complicated. A compound is injected into the area to be cleaned by direct-push applications. This time though, the object is to create strongly reducing conditions so compounds that put hydrogen into the groundwater are used such as ones containing acids. For this method, the concentration of dissolved oxygen in groundwater should decrease and the ORP readings should become strongly negative. There should be an increase in ethane concentrations (author’s personal observations). The time it takes for remediation is very site-dependent and groundwater will need to be sampled several times to monitor concentrations of vinyl chloride to see if the process is working.

Soil:
Vinyl chloride may contaminate the soil by being in a gaseous phase in the vadose zone or by being dissolved in small amounts of water in the pore space. Treating soil contaminated by vinyl chloride may include removing the soil for ex-situ treatment (excavation), pulling the vinyl chloride out by a soil-vapor extraction system (SVE), or treating the soil in place with a recirculating system that pumps water into the soil and extracts it downgradient, a process known as soil-washing (Pichtel, 2007 and NJDEP, 1998). A variant of this system treats the contaminant in-situ instead of ex-situ by injecting water and chemical or biological oxidizers to create a mound of groundwater. This allows unsaturated contaminated soil to become saturated and thus allow the chemical or biological remediating agents to work.
excavation or by injecting the same compounds described above with enough water to temporarily saturate the soil. Systems can be developed to recirculate water through an area that is being treated and keeping the water table elevated in the area of remediation.
This brief summary has described a few of the many methods of remediation available for sites affected by vinyl chloride. The decision on which method to use must be based on the unique characteristics of the site.

Sources

Wong, Richard and Bonsavage, Mark. May 9, 2001. Pilot scale remediation of dissolved vinyl chloride plume using in situ chemical oxidation, IR site 5 – NAS North Island. Accessed from http://www.epa.gov/tio/tsp/download/wong.pdf, Sept 26, 2009.

United States Geological Survey (USGS, 2009) Microbial degradation of chloroethenes in ground water systems. http://toxics.usgs.gov/sites/solvents/chloroethene.html accessed 9/18/09.
Environmental Protection Agency (EPA1) Underground Injection Control Program. http://www.epa.gov/safewater/uic/basicinformation.html. Accessed Sep27, 2009.
Environmental Protection Agency (EPA2) NPDES Permit Program Basics. http://cfpub.epa.gov/npdes/home.%20%20Accessed%20Sep27, 2009.
Pichtel, John. (2007) Fundamentals of site remediation (second edition). Lanham, Maryland: Government Institutes an imprint of The Scarecrow Press, Inc.
New Jersey Department of Environmental Protection (NJDEP) 1998 Revised Guidance Document for the Remediation of Contaminated Soils. http://www.state.nj.us/dep/srp/regs/soilguide/sgd24-52.pdf.%20%20%20Accessed%20September%2027, 2009.

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PVC in the Third World the Hidden Cost
Rob Walker

In Ghana Africa a child laborer “… hoists a tangle of copper wire off the old tire he's using for fuel and douses the hissing mass in a puddle. With the flame retardant insulation burned away—a process that has released a bouquet of carcinogens and other toxics.” (http://ngm.nationalgeographic.com/2008/01/high-tech-trash/carroll-text/1 ; September 19 2009)

http://wwwGreenPeace.org September 19 2009
Others buy computers or TVs. Salvage useable parts then they rip out wiring and burn the plastic. Scenes like this are typical in the growing trade in e-waste. (http://www.youtube.com/watch?v=-j_Zohgg4S8 September 19 2009) Scenes like these are repeated from India to Africa and China. The burning of e-waste produces toxic that damage health and have long turn health consequences.
E-waste trade is a growing problem in many third world countries. But what does e-waste have to do with PVC? PVC makes up a large constituency of the plastics casings and wire insulation that cover copper wire. Plastic casings PVC make up to 6.3 Kg of an average computer. Over a ¼ of all the Plastic used by computer and electronics industry are PVC based plastics (everything2.com/title/e-waste , September 19 2009). In Africa and Third World countries the common practice of copper recover is to burn wire/cords to remove the protective casing. (http://ngm.nationalgeographic.com/2008/01/high-tech-trash/carroll-text/1 ; September 19 2009) Often the casings are PVC based. (everything2.com/title/e-waste , September 19 2009). Most developed countries and some companies have laws and policy that prohibit E-waste from being shipped to developing countries. Some company and shady recycles often conceal e-waste as second hand goods (useable goods) and ship them to developing nations. Once the “second hand goods” reached the developing world it is sold as scrap and is scraped out for its useable part and copper content. (http://ngm.nationalgeographic.com/2008/01/high-tech-trash/carroll-text/1; September 19 2009 (everything2.com/title/e-waste, September 19 2009).
References:
ngm.nationalgeographic.com/2008/01/high-tech-trash/carroll-text/1
everything2.com/title/e-waste
http://ewasteguide.info/e-waste-campaign-gra
http://abcnews.go.com/WN/
Pictures: From Green Peace.org

[i] Benjamin L. Van Duuran “Chemical Structure, reactivity and carcinogenicity of Halohydrocarbons”, , Environmental Health Perspectives, Vol 21 1977
[ii] “Remediation of Vinyl Chloride” ORC Technical Bulletin 2.2.2.3 Oxygen Release Compound http://www.regenesis.com/library/Technical%20Bulletins/ORC/ORC%20Technical%20Bulletin%202.2.2.3.pdf
[iii] Green, T. & Hathway, D.E. “The chemistry and biogenesis of the S-containing
metabolites of vinyl chloride in rats”. Chemico-biological interactions, 17: 137-150
(1977).
[iv] D Hultmark, et al “Ethanol inhibition of vinyl chloride metabolism in isolated rat hepatocytes”
Chemico-biological interactions 01/05/1979; 25(1):1-6.
[v] M.J. Radike, et al “Effect of Ethanol on Vinyl Chloride Carcinogenesis” Environmental Health Perspectives v.41, pp.59-62 1oct1981
[vi] Watanabe, P.G. et al. Fate of [14C] vinyl chloride following inhalation exposure in rats.
Toxicology and applied pharmacology, 37: 49-59 (1976).

[1] Benjamin L. Van Duuran “Chemical Structure, reactivity and carcinogenicity of Halohydrocarbons”, , Environmental Health Perspectives, Vol 21 1977
[1] “Remediation of Vinyl Chloride” ORC Technical Bulletin 2.2.2.3 Oxygen Release Compound http://www.regenesis.com/library/Technical%20Bulletins/ORC/ORC%20Technical%20Bulletin%202.2.2.3.pdf
[1] Green, T. & Hathway, D.E. “The chemistry and biogenesis of the S-containing
metabolites of vinyl chloride in rats”. Chemico-biological interactions, 17: 137-150
(1977).
[1] D Hultmark, et al “Ethanol inhibition of vinyl chloride metabolism in isolated rat hepatocytes”
Chemico-biological interactions 01/05/1979; 25(1):1-6.
[1] M.J. Radike, et al “Effect of Ethanol on Vinyl Chloride Carcinogenesis” Environmental Health Perspectives v.41, pp.59-62 1oct1981
[1] Watanabe, P.G. et al. Fate of [14C] vinyl chloride following inhalation exposure in rats.
Toxicology and applied pharmacology, 37: 49-59 (1976).