A study of Polychlorinated Biphenyls in Deckerville Michigan

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A study of Polychlorinated Biphenyls in
DeckervilleMichigan

• July 9, 2007

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Background of Deckerville

• Location
• Sanilac County Michigan
• 662,000 acres of farmland
• The thumb of Lake Huron
• Approximately 100 Km north of Detroit
• History
• 1870 Charles Decker began a lumber business
• 1893 the village became a stop on the Pere
  Marquette Railroad

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Background of PCBs

• On April 19th 1979 the EPA announced regulations
  banning the production of PCBs and gradually
  phasing out use of PCBs for many industrial uses.
  (1)
• PCBs have been shown to have significant
  ecological and human health effects including
  cancer and developmental toxicity. (2)
• People who eat PCB-contaminated fish face an
  increased risk of cancer and other serious
  medical conditions including developmental,
  immune system, thyroid and reproductive
  problems. (3)

PCB 8 PCB 28
PCB 52
PCB 118
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The Study

• Determining if the contaminants of interest are
  local source of contamination
• Used raw data collected between May of 1992
  through February of 1993
• Used the Clausius-Claperyon Equation to determine
  the enthalpy of vaporization

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PCB 8 2,4-dichlorobiphenyl
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Data analysis

• To use the Clasusius-Clapeyron equation the
• partial pressure in atmospheres,
• calculated from the concentration in ng/m3 by the
  formula P(Concentration/Molar Mass) RT(10-9),
• Partial pressure was graphed verse the
  temperature.
• The slope of that line was divided by the gas
  constant (R) in JK-1mol-1, which is the heat of
  vaporization.

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The heat of vaporization for 2,4-dichlorobiphenyl
at Deckerville, MI

• 18.8 kJ mol-1.
• This does not indicate a local source for this
  congener because it is less then 50 kJ mol-1.

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Regression analysis

• Significance
• F is 1.06 x 10-8 which is less then 0.05
• Not strong because
• R value of 0.60 is less then 0.7.
• A plot of the residuals agrees with the r value

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The Henrys Law Constant

• 0.00023 atm m3 mol-1.

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PCB Congener 28

• Not extremely toxic.
• In general toxicity increases with mass.
• Increased toxicity because of structure.
• Main concern is bioaccumulation in fish.

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Results of Regression
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Results continued
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Calculations

• Enthalpy of Vaporization
• 20.8 KJ mol-1
• Henry's Law Constant
• 0.0002 atm m3 mol-1
• Water Solubility
• 0.27 mg/l
• Henry's Law estimate of P _at_ 298K (saturated)
• 2.1 x 10-7 atm
• Average P 1.1 x 10-15 atm _at_ 282K

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PCB Congener 52

• One of the less toxic congeners of PCB
• Shape
• Number of chlorines
• Was used heavily in the 50s, 60s and 70s
• Fire retardants
• Hydraulic fluids
• Pesticides
• Determined to be carcinogenic
• The manufacturing was discontinued in 76

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Results of Regression
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Results continued

• Summary output data
• R 0.04610811
• Well below the significant value of 0.07
• R2 identifies that approximately 78 of the
  variation is possibly coming from alternate
  sources
• F (sig) 2.76882E-05
• Very significant with a very high level of
  confidence

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Residual
Residual plot shows that the model is appropriate
for the data because no real pattern
persists. There could be some error when looking
at the normality of the variation. The low number
of plotted points could have skewed the data
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Enthalpy of Vaporization

• The calculated value
• 17.544 KJ mol-1
• The value is below the accepted value
• Conclude that the Deckerville site does not have
  a local source of the congener 52
• Henrys Law 2.0E-04 atm-m3/mol

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BIBLIOGRAPHY

• EPA Bans PCB Manufacture Phases Out Uses.
  http//www.epa.gov/history/topics/pcbs/01.htm
  (accessed 7/5/07). EPA press release 4/19/1979.
• PCBs Cancer Dose-Response Assessment and
  Application to Environmental Mixtures. U.S.
  Environmental Protection Agency, Office of
  Research and Development, National Center for
  Environmental Assessment, Washington Office,
  Washington, DC, EPA/600/P-96/001F, 1996.
• EPA Proposes Comprehensive Plan to Clean Up
  Hudson River PCBs. http//www.epa.gov/history/topi
  cs/pcbs/02.htm (accessed 7/5/07). EPA press
  release 12/6/2000.